Details of a Researcher - Fujishiro, Issei

Papers - Fujishiro, Issei

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L2H-NeRF: Low to high frequency guided NeRF for 3D reconstruction with a few input scenes

Taoqi Bao, Jiangnan Ye, Zhankon Bao, Chee Siang Leow, Haoji Hu, Jianfeng Lu, Issei Fujishiro, Jiayi Xu

The Visual Computer (Springer-Verlag) 41 ( 9 ) 6757 - 6768 2025.07

Research paper (scientific journal), Joint Work, Accepted, ISSN 0178-2789

Nowadays, three-dimensional (3D) reconstruction techniques are becoming increasingly important in the fields of architecture, game development, movie production, and more. Due to common issues in the reconstruction process, such as perspective distortion and occlusion, traditional 3D reconstruction methods face significant challenges in achieving high-precision results, even when dense data are used as inputs. With the advent of neural radiance field (NeRF) technology, high-fidelity 3D reconstruction results are now possible. However, high computational resources are usually required for NeRF computations. Recently, a few data inputs are used to ensure the highest quality. In this paper, we propose an innovative low- to highfrequency-guided NeRF (L2H-NeRF) framework that decomposes scene reconstruction into coarse and fine stages. For the first stage, a low-frequency enhancement network based on a vision transformer is proposed, where the low-frequency-based globally coherent geometric structure is recovered, with the dense depth restored in a depth completion way. In the second stage, a high-frequency enhancement network is incorporated, where the high-frequency-related detail is compensated by robust feature alignment across adjacent views using a plug-and-play feature extraction and matching module. Experiments demonstrate that both the accuracy of the geometric structure and the feature detail of the proposed L2H-NeRF outperforms state-of-the-art methods.

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Visual simulation of opal using bond percolation through the weighted Voronoi diagram and the Ewald construction

Soma Yokota, Issei Fujishiro

The Visual Computer Journal (Springer-Verlag) 40 ( 8 ) 5005 - 5016 2024.07

Research paper (scientific journal), Joint Work, Last author, Corresponding author, Accepted, ISSN 01782789

Opal, a renowned gemstone, exhibits an optical phenomenon known as “play of color,” which is classified as a kind of structural color. This unique property makes opal a highly valuable material from the natural science, industry, and humanity perspectives. Opal has a complex internal structure called colloidal polycrystalline, and thus, representations of opal remain unestablished in computer graphics. In this study, to approximate the complex internal structure of opal, we imitate its formation process using the three-dimensional additively weighted Voronoi tessellation and percolation model. Further, we apply path tracing to compute the diffraction patterns of visible light inside opal by utilizing the Ewald construction employed in X-ray diffraction theory. Finally, we achieve a visually plausible output through spectral rendering.

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VigNet: Semiautomatic generation of vignette illustrations from video

Mayu Namai, Issei Fujishiro

IIEEJ Transactions on Image Electronics and Visual Computing (IIEEJ) 12 ( 1 ) 15 - 22 2024.06

Research paper (scientific journal), Joint Work, Last author, Corresponding author, Accepted

A variety of summarization techniques has recently been proposed to manage the growing volume of media data, but most are oriented toward homogeneous media conversion, resulting in a limited compression ratio. In this study, we focus on the creation of a vignette illustration that represents the story in an animation or game briefly and that allows the viewer to understand its world perspective at a glance. If video can be converted into vignette illustration, it is expected to provide a more highly compressed summary of the media information. This paper proposes VigNet, a system that semiautomatically converts an input video into vignette illustrations so they reflect users’ preferences.

Efficient particle-based fluid surface reconstruction using mesh shaders and bidirectional two-level grids

Yuki Nishidate, Issei Fujishiro

ACM Proceedings of Computer Graphics and Interactive Techniques (ACM) 7 ( 1 ) 1 - 14 2024.05

Research paper (scientific journal), Joint Work, Last author, Corresponding author, Accepted

In this paper, we introduce a novel method for particle-based fluid surface reconstruction that incorporates mesh shaders for the first time. This approach eliminates the need to store triangle meshes in a GPU's global memory, resulting in a significant reduction in the amount of memory needed. Furthermore, our method employs a bidirectional two-level uniform grid, which not only accelerates the computationally expensive stage of surface cell detection but also effectively addresses the issue of vertex overflow among the mesh shaders. Experimental results prove that our method outperforms the state-of-the-art method, achieving both acceleration and memory reductions simultaneously, without sacrificing quality. The method is highly practical, with no major limitations other than requiring a GPU that supports the mesh shaders.

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DiffMat: Latent Diffusion Models for Image-Guided Material Generation

Liang Yuan, Dingkun Yan, Suguru Saito,Issei Fujishiro

Visual Informatics (Elsevier) 8 ( 1 ) 6 - 14 2024.03

Research paper (scientific journal), Joint Work, Last author, Corresponding author, Accepted, ISSN 25432656

Creating realistic materials is essential in the construction of immersive virtual environments. While existing techniques for material capture and conditional generation rely on flash-lit photos, they often produce artifacts when the illumination mismatches the training data. In this study, we introduce DiffMat, a novel diffusion model that integrates the CLIP image encoder and a multi-layer, cross-attention denoising backbone to generate latent materials from images under various illuminations. Using a pre-trained StyleGAN-based material generator, our method converts these latent materials into high-resolution SVBRDF textures, a process that enables a seamless fit into the standard physically based rendering pipeline, reducing the requirements for vast computational resources and expansive datasets. DiffMat surpasses existing generative methods in terms of material quality and variety, and shows adaptability to a broader spectrum of lighting conditions in reference images.

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HYDRO: Optimizing interactive hybrid images for digital signage content

Masanori Nakayama, Karin Uchino, Ken Nagao, Issei Fujishiro

Virtual Reality & Intelligent Hardware (Elsevier Science) 5 ( 6 ) 565 - 577 2023.12

Research paper (scientific journal), Joint Work, Last author, Corresponding author, Accepted, ISSN 20965796

In modern society, the digital signage installed in many large-scale facilities supports daily life. However, owing to their limited screen size, it is difficult to simultaneously provide different types of information to many viewers at varying distances from the screen. Therefore, in this study, we extend the existing research on the use of hybrid images for tiled displays. To facilitate smoother information selection, a new interactive display method is proposed that incorporates touch-activated widgets as high-frequency parts of hybrid images. These widgets are novel because they are more visible to viewers near the display. We developed an authoring tool called the hybrid image display resolution optimizer (HYDRO), which features two types of control functions to optimize the visibility of touch-activated widgets in terms of placement and resolution. The effectiveness of the proposed method is demonstrated empirically through a quantitative user study and an eyetracking-based qualitative evaluation.

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Multiview SVBRDF capture from unified shape and illumination

Liang Yuan, Issei Fujishiro

Visual Informatics (Elsevier) 7 ( 3 ) 11 - 21 2023.09

Research paper (scientific journal), Joint Work, Last author, Corresponding author, Accepted, ISSN 25432656

This paper proposes a stable method for reconstructing spatially varying appearances (SVBRDFs) from multiview images captured under casual lighting conditions. Unlike flat surface capture methods, ours can be applied to surfaces with complex silhouettes. The proposed method takes multiview images as inputs and outputs a unified SVBRDF estimation. We generated a large-scale dataset containing the multiview images, SVBRDFs, and lighting appearance of vast synthetic objects to train a two-stream hierarchical U-Net for SVBRDF estimation that is integrated into a differentiable rendering network for surface appearance reconstruction. In comparison with state-of-the-art approaches, our method produces SVBRDFs with lower biases for more casually captured images.

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Visual simulation of crack and bend generation in deteriorated films coated on metal objects: Combination of static fracture and position-based deformation

Akinori Ishitobi, Masanori Nakayama, Issei Fujishiro

The Visual Computer (Springer-Verlag) 39 ( 8 ) 3403 - 3415 2023.08

Research paper (scientific journal), Joint Work, Last author, Accepted, ISSN 0178-2789

Weathering, an expression of degradation caused by rain and wind, is essential for photorealistic computer graphics. One of the commonest targets of weathering is metal, which is omnipresent in reality. However, for the realistic reproduction of scenes, many of which display degradation, the application of rust-proof paint to metal surfaces cannot be ignored. In our study, we propose a weathering method for coated films on metal objects, which are modeled using a three-dimensional (3D) triangular polygon mesh and deformed by combining two kinds of simulations: static simulation, for determining fractures based on the balance of the internal forces, and position-based bend simulation for moving vertices according to geometric constraints. Our method can digitally reproduce the deterioration of coated films using complex 3D deformation, which is difficult to achieve by material manipulation only.

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Controllable automatic generation of non-player characters in 3D anime style

Ruizhe Li, Ryo Oji, Issei Fujishiro

Computer Animation & Virtual Worlds (Wiley) 34 ( 2 ) e2047:1 - e2047:16 2023.03

Research paper (scientific journal), Joint Work, Last author, Corresponding author, Accepted, ISSN 15464261

Game creators always use prefabricated models as non-player characters (NPCs) to create an atmosphere for game scenes. However, players are likely to see different NPCs with the same 3D models because creators usually cannot prepare a high number of NPC models for big game scenes. In this article, we present an anime-like character customization system, where each customizing parameter can adjust the shape or color for the corresponding part of the character model. Based on this system, we propose an improved approach for generating a rich variety of 3D anime-like NPCs including body models and clothing items in different styles. We introduce a neural network to control the facial appearances, Gaussian mixture models to control the colors of hair and clothes, and a Bayesian network to control the outfits of clothing items. We demostrate that the proposed approach can maintain the variety and stability of the generated characters.

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Multi-dimensional time-series subsequence clustering for visual feature analysis of blazar observation datasets

Naoko Sawada, Makoto Uemura, Issei Fujishiro

Astronomy and Computing (Elsevier Science) 41 ( 100663 ) 1 - 12 2022.11

Research paper (scientific journal), Joint Work, Last author, Accepted, ISSN 2213-1337

Exploring hidden structures in subsequences extracted from long-term time-series data is one of the primary tasks of time-series data analysis. Clustering is one of the most commonly used techniques in that context; however, various existing issues must be addressed, such as the way to extract less-overlapping subsequences and the definition of the inter-subsequence similarity. Especially in multi-dimensional data analysis, correlations among variables should also be emphasized. To boost users’ exploration of the universalities of subsequences, we incorporate multi-dimensional time-series subsequence clustering methods and visual clustering analysis interface into TimeTubesX, which is an integrated visual analytics environment for multi-dimensional time-dependent observation datasets of blazars. TimeTubesX extracts and filters subsequences with various lengths according to the characteristics of the data and clusters them automatically in consideration of correlations among observed attributes. And then, it allows users to visually examine the clustering results in terms of the cluster features, intercluster transitions, and temporal distributions of clusters. Through the application to two practical case studies, we demonstrate how the enhanced TimeTubesX enables users to see not only instances but also universalities (i.e., time-series motifs or cluster prototypes) in time-series observations of blazars.

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FORSETI: A visual analysis environment enabling provenance awareness for the accountability of eautopsy reports

Baoqing Wang, Noboru Adachi, Issei Fujishiro

Visual Informatics (Elsevier Science) 6 ( 3 ) 69 - 80 2022.09

Research paper (scientific journal), Joint Work, Last author, Corresponding author, Accepted, ISSN 25432656

Autopsy reports play a pivotal role in forensic science. Medical examiners (MEs) and diagnostic radiologists (DRs) cross-reference autopsy results in the form of autopsy reports, while judicial personnel derive legal documents from final autopsy reports. In our prior study, we presented a visual analysis system called the forensic autopsy system for e-court instruments (FORSETI) with an extended legal medicine markup language (x-LMML) that enables MEs and DRs to author and review e-autopsy reports. In this paper, we present our extended work to incorporate provenance infrastructure with authority management into FORSETI for forensic data accountability, which contains two features. The first is a novel provenance management mechanism that combines the forensic autopsy workflow management system (FAWfMS) and a version control system called lmmlgit for x-LMML files. This management mechanism allows much provenance data on e-autopsy reports and their documented autopsy processes to be individually parsed. The second is provenance-supported immersive analytics, which is intended to ensure that the DRs’ and MEs’ autopsy provenances can be viewed, listed, and analyzed so that a principal ME can author their own report through accountable autopsy referencing in an augmented reality setting. A fictitious case with a synthetic wounded body is used to demonstrate the effectiveness of the provenance-aware FORSETI system in terms of data accountability through the experience of experts in legal medicine.

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3D distance field-based apparel modeling

Masanori Nakayama, Takami Yamamoto, Issei Fujishiro

IIEEJ Transactions on Image Electronics and Visual Computing (IIEEJ) 10 ( 1 ) 55 - 65 2022.06

Research paper (scientific journal), Joint Work, Last author, Accepted

This study aims to design an apparel item by converting a polygon model of the human body obtained through a 3D scan into a volume model. From the model, we can quickly generate a curved surface that retains a constant distance from the surface of the body, thus being able to design an apparel item that ensures accurate allowance by defining the distance field for the surface of the body. The curved surface, which would be an ideal garment that can envelop the body, can be generated by tweaking the threshold value for an isosurface from the surface of the body. Furthermore, by drawing design lines on the curved surface, the pattern required for actual sewing can be designed in 3D space. The curved surface trimmed by the design lines is converted into a polygon mesh. A dynamics simulation is applied to smooth the curvatures so that the desired flat surface pattern can be obtained. As a result of actually sewing the virtually designed pattern and trying it on, it was shown that we can generate clothes with the appropriate allowance and proportions.

Illumination-aware group portrait compositor

Masaru Ohkawara，Issei Fujishiro

The Visual Computer (Springer-Verlag) 38 ( 12 ) 4009 - 4018 2022.05

Research paper (scientific journal), Joint Work, Last author, Accepted, ISSN 01782789

We present a novel compositing framework for full-length human figures that maintains their surface details and appends the localized nature of light and shadow, thereby synthesizing composite results with high visual coherence. The framework is extended from the compositing pipeline proposed in our previous study so that it deploys five stages for photometric information estimation, as well as for 3D reconstruction, global illumination simulation, lighting transfer, and compositing. Based on the interpretation that a sense of coexistence can be achieved through visual coherence, we demonstrate that the proposed framework functions properly as a group portrait compositor. The composite results that the proposed framework composed the images separately rendered 3D human models compared favorably with the results which rendered multiple avatars together. Based on this empirical evaluation, the proposed framework is expected as a new means of fostering a sense of coexistence in remote societies and of efficiently generating highly photorealistic cyberworlds.

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LineM: Assessing metamorphopsia symptom using line manipulation task

Zhenyang Zhu, Masahiro Toyoura, Issei Fujishiro, Kentaro Go, Kenji Kashiwagi, Xiaoyang Mao

The Visual Computer (Springer-Verlag) 38 ( 5 ) 1607 - 1617 2022.05

Research paper (scientific journal), Joint Work, Accepted, ISSN 01782789

Metamorphopsia patients experience distortions in their views. The number of metamorphopsia patients is arising with the increase in the elderly population. For early detection of metamorphopsia, examination approaches have been proposed. However, none of the existing methods can be employed to precisely assess the perceptions of patients. We propose LineM as a novel method to precisely measure the distorted views of metamorphopsia patients based on interactive line manipulation task involving the patients. To explore the potential of LineM, a case study which uses the measured results from LineM to visualize the distorted views of metamorphopsia patients is presented. Furthermore, a novel technique for compensating the distorted views of individual metamorphopsia patients using the results from LineM is also presented. Considering that elderly individuals account for the majority of metamorphopsia patients, an intuitive and user-friendly prototype system has been implemented. The effectiveness and usability of LineM and the compensation method were demonstrated via a qualitative and subjective experiment that involved metamorphopsia patients and elderly participants.

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TimeTubesX: A query-driven visual exploration of observable, photometric, and polarimetric behaviors of blazars

Naoko Sawada, Makoto Uemura, Johanna Beyer, Hanspeter Pfister, Issei Fujishiro:

IEEE Transactions on Visualization and Computer Graphics (IEEE) 28 ( 4 ) 1917 - 1929 2022.04

Research paper (scientific journal), Joint Work, Last author, Accepted, ISSN 1077-2626

Blazars are celestial bodies of high interest to astronomers. In particular, through the analysis of photometric and polarimetric observations of blazars, astronomers aim to understand the physics of the blazar's relativistic jet. However, it is challenging to recognize correlations and time variations of the observed polarization, intensity, and color of the emitted light. In our prior study, we proposed TimeTubes to visualize a blazar dataset as a 3D volumetric tube. In this paper, we build primarily on the TimeTubes representation of blazar datasets to present a new visual analytics environment named TimeTubesX, into which we have integrated sophisticated feature and pattern detection techniques for effective location of observable and recurring time variation patterns in long-term, multi-dimensional datasets. Automatic feature extraction detects time intervals corresponding to well-known blazar behaviors. Dynamic visual querying allows users to search long-term observations for time intervals similar to a time interval of interest (query-by-example) or a sketch of temporal patterns (query-by-sketch). Users are also allowed to build up another visual query guided by the time interval of interest found in the previous process and refine the results. We demonstrate how TimeTubesX has been used successfully by domain experts for the detailed analysis of blazar datasets and report on the results.

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Personalized image recoloring for color vision deficiency compensation

Zhenyang Zhu, Masahiro Toyoura, Kentaro Go, Kenji Kashiwagi, Issei Fujishiro, Tien-Tsin Wong, Xiaoyang Mao

IEEE Transactions on Multimedia (IEEE) 24 1721 - 1734 2022.04

Research paper (scientific journal), Joint Work, Accepted, ISSN 1520-9210

Several image recoloring methods have been proposed to compensate for the loss of contrast caused by color vision deficiency (CVD). However, these methods only work for dichromacy (a case in which one of the three types of cone cells loses its function completely), while the majority of CVD is anomalous trichromacy (another case in which one of the three types of cone cells partially loses its function). In this paper, a novel degree-adaptable recoloring algorithm is presented, which recolors images by minimizing an objective function constrained by contrast enhancement and naturalness preservation. To assess the effectiveness of the proposed method, a quantitative evaluation using common metrics and subjective studies involving 14 volunteers with varying degrees of CVD are conducted. The results of the evaluation experiment show that the proposed personalized recoloring method outperforms the state-of-the-art methods, achieving desirable contrast enhancement adapted to different degrees of CVD while preserving naturalness as much as possible.

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Enhancing edge indicator for visual field loss compensation for homonymous hemianopia patients

Keisuke Ichinose, Xi Zhao, Issei Fujishiro, Masahiro Toyoura, Kenji Kashiwagi, Kentaro Go, Xiaoyang Mao

The Visual Computer (Springer-Verlag) 38 ( 4 ) 1263 - 1273 2022.04

Research paper (scientific journal), Joint Work, Accepted, ISSN 0178-2789

Homonymous hemianopia (HH) is a visual field defect in which the same side of both eyes is blind. In this paper, we propose an out-of-visual-field information compensation system for HH patients using an optical see-through head-mounted display. In the proposed system, in order to reduce the obstruction in the remaining visual field, indicators are placed at the boundary between the remaining visual field and the defective part to notify the HH patient about the events occurring at the blinded side of the visual field. Two different kinds of indicators, namely brightness-based and flicker-based, are designed to visualize the spatial information of the events. We conducted experiments with simulated HH participants to verify the effectiveness of the proposed system and compare the two designed indicators, as well as an existing method that makes use of the overlay overview window. The experimental results proved that the proposed system can react more intuitively and is faster than the existing method in the part near the central visual field. Moreover, it can alleviate the obstruction problem of the existing method.

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FORSETI: A visual analysis environment for authoring autopsy reports in extended legal medicine mark-up language

Baoqing Wang, Yume Asayama, Malik Olivier Boussejra, Hideki Shojo, Noboru Adachi, Issei Fujishiro

The Visual Computer (Springer-Verlag) 37 ( 12 ) 2951 - 2863 2021.06

Research paper (scientific journal), Accepted, ISSN 1432-2315

In forensic autopsy, medical examiners (MEs) and diagnostic radiologists (DRs) cooperate with each other to perform an autopsy of the corpse. Effective computational assistance tools are imperative for facilitating the intricate collaborative work involved in the autopsy. In this paper, we present an integrated visual analysis environment named FORSETI (forensic autopsy system for e-court instruments), whose technical essence is two-fold. The first is to be designed on the basis of an extended version of legal medicine mark-up language for authoring reports on physical autopsy (PA) as well as on virtual autopsy (VA). The second lies in autopsy juxtaposition, which seamlessly assists the MEs and DRs in referring to the VA and PA works, respectively. A fictitious case with the Visible Female Dataset is used to demonstrate the effectiveness of an initial prototype of the FORSETI system.

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Experiencing GPU path tracing in online courses

Masaru Ohkawara, Hideo Saito, Issei Fujishiro

Graphics and Visual Computing (Elsevier Science) 4 200022:1 - 200022:10 2021.06

Research paper (scientific journal), Joint Work, Accepted

In consideration of interdependency between image sensing/recognition (computer vision, CV) and 3D image synthesis (computer graphics, CG) in visual computing, Keio University, Department of Information and Computer Science, reorganized its first course on CV and CG in the undergraduate program into a series of three courses on visual computing in the 2019 academic year. One salient feature of these courses is its newly introduced programming assignment with two specific goals: to experience GPU computing and to understand the path tracing algorithm. The purpose is to help students easily understand the trend in visual computing and vividly envision the future CG area. Specifically, two types of tasks were given to students: material design and analysis of the relationship between sampling and noise. The educational material builds on Google Colaboratory, a cloud-based development environment, to be independent of the students’ hardware. Owing to the judicious design, students can unhesitatingly work on the programming assignment with relatively inexpensive hardware, such as laptop PCs, tablets, or even smartphones, whenever they have a standard off-campus network environment. In the second academic year (2020) of these courses, this type of exercise was especially valuable for students who had to take the courses online because of the COVID-19 pandemic. The effects of the new courses with the educational materials were empirically proven in terms of quantitative and qualitative perspectives.

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Different eye movement behaviors related to artificial visual field defects---A pilot study of video-based perimetry

Changtong Mao, Kentaro Go, Yuichiro Kinoshita, Kenji Kashiwagi, Masahiro Toyoura, Issei Fujishiro, Jianjun Li, Xiaoyang Mao

IEEE Access (IEEE) 9 77649 - 77660 2021.05

Research paper (scientific journal), Joint Work, Accepted, ISSN 2169-3536

Visual field defects (VFDs) can be caused by numerous diseases, some of those (e.g.,glaucoma) are the main causes of blindness in humans. The present perimetry, which is defined as the measurement of visual field function, has high requirements for patients such as long-term fixation, reliable interaction with the system. In this pilot study, we combined the videos and eye tracking techniques in a free-watching task, explored the different eye movement behaviors of people with several types of artificial VFDs, such as hemianopia, altitudinal VFDs, and tunnel vision. We carried out the task in gaze-contingent modality, 38 participants with normal vision were recruited to watch a group of videos monocularly. The eye gaze data were recorded by the tracker during the task. We hypothesized that people with simulated VFDs will produce a more active eye movement coping mechanism to compensate for their visual field disadvantage. A new measurement called eye movement amount (MA) was proposed to describe the amount of eye movement toward a specific direction. Statistically significant differences caused by artificial VFDs were observed by comparing the MA values between the VFD groups and the control group. In addition, we found artificial hemianopia and inferior VFD lead participants to produced increased MA in horizontal and vertical directions respectively. Artificial tunnel vision, on the contrary, induces a decreased MA in both horizontal and vertical directions. The proposed metrics can be used as potential biomarkers for distinguishing VFDs in video free-watching task.

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Ambient Music co-Player: Generating affective video in response to impromptu music performance

Issei Fujishiro, Anri Kobayashi

ITE Transactions on Media Technology and Applications (The Institute of Image Information and Television Engineers ) 9 ( 1 ) 2 - 12 2021.01

Research paper (scientific journal), Joint Work, Accepted, ISSN 2186-7364

When a musical instrument player performs music, the accompanying visual information can have a significant effect on the performance. In this paper, we present an ambient music co-player (AMP) as a system that generates background videos in response to the impromptu performance of a single musical instrument player. The AMP system evaluates the performance to interpret the real player's emotional impression and generates an influential video based on the results of the evaluation. The player tends to change their performance while being inspired by the generated video, further triggering the system to modify the video. The AMP system aims to establish an affective loop where the system continues applying stimuli to the performance of the real player. The final goal of this study is to make the system act as a “co-player” of the player and to amplify the quality of the player's performing experience entirely through interactions between the two. By conducting a user evaluation, it was proven that the AMP system was able to inspire an amateur guitarist as the subject through affective video generation and to make his performance better than when playing alone.

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Visual simulation of weathering coated metallic objects

Akinori Ishitobi, Masanori Nakayama, Issei Fujishiro

The Visual Computer (Springer-Verlag) 36 ( 10-12 ) 2383 - 2393 2020.09

Research paper (scientific journal), Joint Work, Accepted, ISSN 0178-2789

Weathering, referring to techniques for depicting outdoor objects as having suffered rain and wind damage, has a long history of research, and many methods can be found in the literature. Metal is a representative target of weathering, as metallic surface corrosion is a widespread deterioration phenomenon in our daily life. However, few weathering methods consider the effects of rust-preventive paint, while real metal is usually treated with a preservative. This paper presents a novel procedural method for weathering coated metal objects. In our method, a coated surface is imposed on a 3D triangular mesh. We enable the mechanical deterioration of coating film, and we deform the mesh model to express cracking and peeling. As further defacing elements on the coating film, runoff rust and darkening are reproduced by changing the color and reflectance of the surface. Besides, by locally adjusting the control parameters of the designated areas on the surface, the process of deterioration can be arbitrarily directed. Several visual simulation results are shown to prove empirically the faithfulness of the proposed methods.

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Enhancing visual performance of hemianopia patients with overview window

Xi Zhao, Issei Fujishiro, Kentaro Go, Masahiro Toyoura, Kenji Kashiwagi, Xiaoyang Mao

Computers & Graphics (Elsevier) 89 59 - 67 2020.06

Research paper (scientific journal), Joint Work, Accepted

Visual field defect (VFD) is a type of ophthalmic disease that causes the loss of part of the patient’s field of view (FoV). In this paper, we propose a method to enlarge the restricted FoV with an optical see-through head-mounted display (OST-HMD) equipped with a camera that captures an overview and overlays it on the persisting FoV. Because the overview window occludes the real background scene, it is important to create a balance between the augmented contextual information and the unscreened local information. We recruited twelve participants and conducted an experiment to seek the best size, position, and opacity for the overview window through a Whac-A-Mole task (a touchscreen game). We found that the performance was better when the overview window was of medium size (FoV of 9.148 degree x 5.153 degree, nearly one third of FoV of the used OST-HMD) and placed lower in the visual field. Either too large or too small a size decreases the performance. The performance increases with increased opacity. The obtained results can legitimate the default setting for the overview window.

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An immersive virtual environment for visualization of complex and/or infinitely distant territory

Atsushi Miyazawa, Masanari Nakayama, Issei Fujishiro

Transactions on Computational Science XXXVI (Special Issue on Cyberworlds abd Cybersecurity) (Springer LNCS) ( 12060 ) 64 - 78 2020

Joint Work, Accepted

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ALCC-glasses: Arriving light chroma controllable optical see-through head- mounted display system for color vision deficiency compensation

Ying Tang, Zhenyang Zhu, Masahiro Toyoura, Kentaro Go, Kenji Kashiwagi,Issei Fujishiro, Xiaoyang Mao

Applied Sciences (MDPI) 10 ( 7 ) 2381 2020

Research paper (scientific journal), Joint Work, Accepted

About 250 million people in the world suffer from color vision deficiency (CVD).Contact lenses and glasses with a color filter are available to partially improve the vision of people with CVD. Tinted glasses uniformly change the colors in a user’s field of view (FoV), which can improve the contrast of certain colors while making others hard to identify. On the other hand,an optical see-through head-mounted display (OST-HMD) provides a new alternative by applying a controllable overlay to a user’s FoV. The method of color calibration for people with CVD, such as the Daltonization process, needs to make the calibrated color darker, which has not yet been featured on recent commercial OST-HMDs. We propose a new approach to realize light subtraction on OST-HMDs using a transmissive LCD panel, a prototype system, named ALCC-glasses, to validate and demonstrate the new arriving light chroma controllable augmented reality technology for CVD compensation.

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Visual simulation of tearing papers taking anisotropic fiber structure into account

Saeko Shinozaki, Masanori Nakayama, Issei Fujishiro

IIEEJ Transactions on Image Electronics and Visual Computing (IIEEJ) 7 ( 2 ) 106 - 115 2019.12

Joint Work, Last author, Corresponding author, Accepted

Real paper gets deformed anisotropically due to a uni-directional placement of the inner fibers. Few existing CG researchers allow for such fibers to represent virtual papers, and thus anisotropic paper deformation has not been well represented. In this study, we present a two-dimensional visual simulation model for anisotropic papers, which abstracts mutual mechanical relationships among intersecting fibers by a network of filler and hinge springs, and incorporates connection points for keeping the shape of each bended fiber. By releasing the network connections when the filler and hinge spring extend above a certain limit, the paper provides a plausible tear. We succeeded in generating a different appearance of the torn-off line of papers according as the pulling direction.

aflak: Visual programming environment with macro support for collaborative and exploratory astronomical analysis

Malik Olivier Boussejra, Rikuo Uchiki, Shunya Takekawa, Kazuya Matsubayashi, Yuriko Takeshima, Makoto Uemura, Issei Fujishiro

IIEEJ Transactions on Image Electronics and Visual Computing (IIEEJ) 7 ( 2 ) 116 - 127 2019.12

Joint Work, Accepted

This paper describes an extendable graphical framework,aflak, which provides a collaborative visualization environment for the analysis of multi-spectral astronomical datasets. aflak allows the astronomer to share and define analytic pipelines through a node editing interface, in which the user can compose together a set of built-in transforms (e.g. dataset import, integration, Gaussian fit) over astronomical datasets. Not only is aflak fast and responsive,but its macro can be conveniently exported, imported and shared among researchers using a custom data interchange format. aflak,while providing domain-specific features for astronomy,enables collaboration through shareability,guarantees end-to-end provenance management and achieves astronomer-in-the-loop. This paper compares aflak with conventional tools used in astronomy for specific use cases,such as the computing of equivalent widths. Finally,the paper demonstrates that aflak provides a reference implementation for the Provenance DM data model.

An immersive virtual environment for visualization of complex and/or infinitely distant territory

Atsushi Miyazawa, Masanari Nakayama, Issei Fujishiro

Springer Transactions on Computational Science (Special Issue on Cyberworlds 2018) (Springier) 2019.06

Joint Work, Last author, Accepted

With the advent of the high-performance graphics and networking technologies that enable us to create virtual worlds networked via the Internet, various virtual environments have been developed to support mathematics education at around the beginning of the 21st century. In the environments that have been inherently two- or threedimensional Euclidean, students have discovered and experienced mathematical concepts and processes in almost the same ways that they can do in real life. Although elementary mathematics, for instance, calculus and linear algebra, plays an essential role in areas of understanding and knowledge to solve real-world problems, there are traditionally three general areas in pure mathematics for advanced problem-solving techniques: algebra, analysis, and geometry. So, using Virtual Reality (VR) as a general and advanced tool for mathematics education to support students not only in the primary and secondary, also in higher education,the virtual environment ideally provides a wide variety of mathematical domains as possible. We present an immersive virtual environment that allows the user to set environmental limits beyond three-dimensional Euclidean space. More specifically, by setting the limits to n-dimensional complex projective space, an element of both complex and infinitely distant domain can be naturally visualized as a recognizable form in the Euclidean 3-space. The problem here is that the higher the level of mathematics, the more the visualization method tends to become abstract that only experts with advanced degrees can fathom. We also show how our figurative approach is essential for bridging the gap between elementary and more advanced mathematical visualizations.

Processing images for redgreen dichromats compensation via naturalness– and information– preservation considered recoloring

Zhenyang Zhu, Masahiro Toyoura, Kentaro Go, Issei Fujishiro; Kenji Kashiwagi, Xiaoyang Mao

The Visual Computer (Springer) 34 ( 6-8 ) 1053 - 1066 2019.06

Research paper (scientific journal), Joint Work, Accepted, ISSN 01782789

Color vision deficiency (CVD) is caused by anomalies in the cone cells of the human retina. It affects approximately 200 million individuals throughout the world. Although previous studies have proposed compensation methods, contrast and naturalness preservation have not been adequately and simultaneously addressed in the state-of-the-art studies. This paper focuses on red–green dichromats’ compensation and proposes a recoloring algorithm that combines contrast enhancement and naturalness preservation in a unified optimization model. In this implementation, representative color extraction and edit propagation methods are introduced to maintain global and local information in the recolored image. The quantitative evaluation results showed that the proposed method is competitive with state-of-the-art methods. A subjective experiment was also conducted and the evaluation results revealed that the proposed method obtained the best scores in preserving both naturalness and information for individuals with severe red–green CVD.

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Naturalness–and information–preserving image recoloring for redgreen dichromats

Zhenyang Zhu, Masahiro Toyoura, Kentaro Go, Issei Fujishiro, Kenji Kashiwagi, Xiaoyang Mao

Signal Processing: Image Communication 76 ( 6880 ) 68 - 80 2019.04

Research paper (scientific journal), Joint Work, ISSN 09235965

© 2019 The Authors More than 100 million individuals around the world suffer from color vision deficiency (CVD). Image recoloring algorithms have been proposed to compensate for CVD. This study has proposed a new recoloring algorithm to make up shortages of contrast enhancement and naturalness preservation of the state-of-the-art methods. The recoloring task is formulated as an optimization problem that is solved by using the colors in a simulated CVD color space to maximize contrast and to preserve the original color as much as possible. In addition, the dominant colors are extracted for recoloring. They are then propagated to the whole image so that the optimization problem could be solved at a reasonable cost independent of the image size. In the quantitative evaluation, the results of the proposed method are competitive with those of the best existing method. The evaluation involving subjects with CVD demonstrates that the proposed method outperforms the state-of-the-art method in preserving both the information and the naturalness of images.

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aﬂak: Visual programming environment enabling endto-end provenance management for the analysis of astronomical datasets

Malik Olivier Boussejra, Kazuya Matsubayashi, Yuriko Takeshima, Shunya Takekawa, Rikuo Uchiki, Makoto Uemura, #Issei Fujishiro(/)-#HR

Visual Informatics (Elsevier Science) 3 ( 1 ) 1 - 8 2019.03

Research paper (scientific journal), Joint Work, Accepted

© 2019 Zhejiang University and Zhejiang University Press This paper describes an extendable graphical framework, aflak, which provides a visualization and provenance management environment for the analysis of multi-spectral astronomical datasets. Via its node editor interface, aflak allows the astronomer to compose transforms on input datasets queryable from public astronomical data repositories, then to export the results of the analysis as Flexible Image Transport System (FITS) files, in a manner such that the full provenance of the output data be preserved and reviewable, and that the exported file be usable by other common astronomical analysis software. FITS is the standard of data interchange in astronomy. By embedding aflak's provenance data into FITS files, we both achieve interoperability with existing software and full reproducibility of the process by which astronomers make discoveries.

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Visual analysis for the compositional process of composers in Spectral School

TAKAKURA Yuriko, NAKAYAMA Masanori, FUJISHIRO Issei

IIEEJ Transactions on Image Eletronics and Visual Computing (IIEEJ) 6 ( 1 ) 22 - 33 2018.06

Research paper (scientific journal), Accepted

We propose a visual analysis approach for exploring the compositional process of composers in the Spectral School, with a particular focus on its sub-processes of sound analysis and synthesis. Spectral music has been one of the significant trends in contemporary music since the 1970s. Composers in the Spectral School use the acoustic properties of sounds as the basis of their compositional materials. One of the representative software systems they use is AudioSculpt, developed by IRCAM. We develop an accompanying system with AudioSculpt to manage the history of creating sounds with spectral analysis of sound materials. The salient feature of our system lies in its tessellated spectrogram space whose axes represent the elapsed time of the sound and the progress of composition. On the pixel-oriented, spatial substrate, the system makes it possible for users to analyze the compositional processes by using dedicated interactive manipulations. The present system can also be regarded as an initial attempt at managing the provenance of time-series events in the music visualization field. Our approach is intended to pave the way for composers and musicologists to analyze, develop, and share the compositional methodologies.

TideGrapher: Visual analytics of tactile situations for rugby matches

Yusuke Ishikawa, Issei Fujishrio

Visual Informatics (Elsevier) 2 ( 1 ) 60 - 70 2018.03

Research paper (scientific journal), Joint Work, Last author, Corresponding author, Accepted

Various attempts at exploiting information visualization for sports have recently been reported in the literature, although it is still challenging to analyze continuous ball matches. In this paper, we propose a novel visual analytics system, called TideGrapher, to track the transition of tactile situations in a rugby match. With a particular focus on the side position of the ball, we designed a dedicated spatial substrate based on the spatio-temporal trajectory of the ball and provided a set of basic interactions. Quantitative analysis was strengthened by adding a new index, called initiative, to commonly used possession (ball occupation) and territory (dominance of territory). The feasibility of the proposed visual analytics system was proven empirically through application to datasets from real amateur and professional matches.

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TimeTubes: Visualization of polarization variations in blazars

UEMURA Makoto, ITOH Ryosuke, XU Longyin, NAKAYAMA Masanori, WU Hsiang-Yun, WATANABE Kazuho, TAKAHASHI Shigeo, FUJISHIRO Issei

Galaxies (MDPI) 4 ( 3 ) 2016.09

Research paper (scientific journal), Joint Work, Accepted

Optical polarization provides important clues to the magnetic field in blazar jets. It is easy to find noteworthy patterns in the time-series data of the polarization degree (PD) and position angle (PA). On the other hand, we need to see the trajectory of the object in the Stokes QU plane when the object has multiple polarized components. In this case, ironically, the more data we have, the more difficult it is to gain any knowledge from it. Here, we introduce TimeTubes, a new visualization scheme to explore the time-series data of polarization observed in blazars. In TimeTubes, the data is represented by tubes in 3D (Q, U, and time) space. The measurement errors of Q and U, color, and total flux of objects are expressed as the size, color, and brightness of the tubes. As a result, TimeTubes allows us to see the behavior of six variables in one view. We used TimeTubes for our data taken by the Kanata telescope between 2008 and 2014. We found that this tool facilitates the recognition of the patterns in blazar variations; for example, favored PA of flares and PA rotations associated with a series of flares.

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Applying manifold learning to plotting approximate contour trees

TAKAHASHI Shigeo, FUJISHIRO Issei, OKADA Makoto

IEEE Transactions on Visualization and Computer Graphics (IEEE) 15 ( 6 ) 1185 - 1192 2009.10

Research paper (scientific journal), Joint Work, Accepted

A contour tree is a powerful tool for delineating the topological evolution of isosurfaces of a single-valued function, and thus has been frequently used as a means of extracting features from volumes and their time-varying behaviors. Several sophisticated algorithms have been proposed for constructing contour trees while they often complicate the software implementation especially for higher-dimensional cases such as time-varying volumes. This paper presents a simple yet effective approach to plotting in 3D space, approximate contour trees from a set of scattered samples embedded in the high-dimensional space. Our main idea is to take advantage of manifold learning so that we can elongate the distribution of high-dimensional data samples to embed it into a low-dimensional space while respecting its local proximity of sample points. The contribution of this paper lies in the introduction of new distance metrics to manifold learning, which allows us to reformulate existing algorithms as a variant of currently available dimensionality reduction scheme. Efficient reduction of data sizes together with segmentation capability is also developed to equip our approach with a coarse-to-fine analysis even for large-scale datasets. Examples are provided to demonstrate that our proposed scheme can successfully traverse the features of volumes and their temporal behaviors through the constructed contour trees.

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Parallel visualization of gigabyte datasets in GeoFEM

FUJISHIRO Issei,Li Chen,TAKESHIMA Yuriko,NAKAMURA Hiroko,SUZUKI Yasuko

Concurrency and Computation: Practice and Experience 14 ( 6-7 ) 521 - 530 2002.05

Research paper (scientific journal), Joint Work, Accepted

Volume data mining using 3D ﬁeld topology analysis

FUJISHIRO Issei,AZUMA Taeko,TAKESHIMA Yuriko,TAKAHASHI Shigeo

IEEE Computer Graphics and Applications 20 ( 5 ) 46 - 51 2000.09

Research paper (scientific journal), Joint Work, Accepted

Volumetric data exploration using interval volume

FUJISHIRO Issei,MAEDA Yuji,SATO Hiroshi,TAKESHIMA Yuriko

IEEE Transactions on Visualization and Computer Graphics 2 ( 2 ) 144 - 155 1996.06

Research paper (scientific journal), Joint Work, Accepted

A note on cyclic reduction Poisson solvers with application to bioconvective phenomena problem

FUJISHIRO Issei,IKEBE Yasuhiko,HARASHIMA Akira,WATANABE Masataka

Computers & Fluids 17 ( 3 ) 419 - 435 1989

Research paper (scientific journal), Joint Work, Accepted

Evolution of bioconvection patterns in a culture of motile ﬂagellates

HARASHIMA Akira,WATANABE Masataka,FUJISHIRO Issei

The Physics of Fluids 31 ( 4 ) 764 - 775 1988.04

Research paper (scientific journal), Joint Work, Accepted

Hierarchical representations of 2D/3D gray-scale images and their 2D/3D two-way conversion

Xiaoyang Mao,Tosiyasu L. Kunii,FUJISHIRO Issei,NOMA Tsukasa

IEEE Computer Graphics and Applications 7 ( 12 ) 37 - 44 1987.12

Research paper (scientific journal), Joint Work, Accepted

G-quadtree: A hierarchical representation of gray-scale digital images

KUNII Tosiyasu L., FUJISHIRO Issei, MAO Xiaoyang

The Visual Computer (Springer-Verlag) 2 ( 4 ) 219 - 226 1986.08

Research paper (scientific journal), Joint Work, Accepted

PolySlerp：球面多角線形補間

中山雅紀，藤代一成

画像電子学会誌 (画像電子学会) 54 ( 4 ) 384 - 394 2025.10

Research paper (scientific journal), Joint Work, Last author, Corresponding author, Accepted

本論文は，n次元実数空間Rn の単位ベクトル群を，球面幾何学に基づいて，ベクトル長を保持しつつ加重平均する新たな手法を提案する．この手法は，球面S^{n−1}上の複数の頂点に対する重心座標系の定義に相当する．従来から，2本の単位ベクトル間では球面線形補間(Spherical Linear Interpolation: Slerp) が広く用いられてきたが，3本以上の単位ベクトル間の加重平均には，球面幾何学的な正当性を欠く近似的な手法しか存在しなかった．提案手法は，Slerp を拡張した独自のベクトル演算子を導入することでこの課題を解決し，単位ベクトルを保ったまま加重平均(PolySlerp) を実現する．さらに，このベクトル演算子を用いることで，球面上の点列に基づくスプライン曲線の生成や，球面多角形における重心座標系の定義が可能であることを示す．基本的に球面上の曲線は，ユークリッド空間における既存の曲線手法を球面へ拡張することで得られる．しかし，その例は従来，Bezier曲線やB-spline曲線などに限られていた．これは，それらがde Casteljauやde Boorに代表される再帰的な線形補間(Linear Interpolation: Lerp) によって定義できる特殊な曲線であり，Lerp をSlerp に置換することで球面への拡張が容易であったためである．しかし，本来，曲線は離散的なデータ列をフィルタリングして平滑化する信号処理であり，あらゆる基底関数が想定できる．例えば，画像の補間手法として一般的なLanczos補間も，sinc関数を基底関数とした一種の曲線手法であるといえる．このとき，我々の提案するPolySlerp によって，球面上での加重平均（線形ブレンド）が行えるということは，ユークリッド空間における様々な既存の信号処理手法を，そのまま球面上へ拡張できることを意味する．したがって本手法は，モデリング，アニメーション，ロボティクス，空間データ解析など幅広い分野で利用されている単位四元数の補間において，重要な役割を果たすことが期待される．

Frame-Break：アナモルフォーシスを用いた裸眼立体映像の立体感の強化

徳永恵太，藤代一成

画像電子学会誌 (画像電子学会) 54 ( 4 ) 405 - 411 2025.10

Research paper (scientific journal), Joint Work, Last author, Corresponding author, Accepted

徳永らはアナモルフォーシスとよばれるデザイン技法を応用した裸眼立体視システムを提案している．このシステムでは，運動視差を誘発することでユーザに立体感を与えているが，オブジェクトの位置とユーザの視点位置によってはオブジェクトに見切れが発生し，立体感を低下させることが問題として挙げられている．本論文では,この問題を解決するために，近年，立体広告などでも利用されているframe-break という手法を，このシステムに組み込むことを提案し，実際に立体感を増強する効果を検証する．

MoNACA: 関節軌道曲線の適応的分割によるセルアニメ風モーション変換システム

小六優依，藤代一成

芸術科学会論文誌 (芸術科学会) 23 ( 3 ) 6:1 - 6:17 2024.09

Research paper (scientific journal), Joint Work, Last author, Corresponding author, Accepted, ISSN 1347-2267

3DCGにおけるキャラクタアニメーションでは，セルアニメのような手描きらしい動作を表現するために，コマ打ちを用いることがある．セルアニメにおけるコマ打ちは，少ないポーズ数で動作を表現するために，余剰な動作を省略し，速さを強調するため，現実動作とは異なる質感をもっている．したがって，現実動作に一様なダウンサンプリング処理を施しても，セルアニメに特有な動作の質感までは再現しづらい．そこで本論文では，モーションキャプチャデータをセルアニメらしい動作へ変換するシステムMoNACA(Motion transfer by Nakawari Adaptation for Cel-anime Articular trajectories)を提案する．MoNACAでは，動作の余剰性と距離配分を考慮することで軌道曲線を純化し，その関節軌道から分割点群を選択することで，中割ポーズ群を決定する．さらに，セルアニメの平面性を再現するために微小回転を省略し，動作の視認性を高めるための最適視点位置を自動で決定する．変換動作およびシステム機能に対する評価実験により，MoNACAは，既存手法と比べ，より魅力的な動作変換を効率的に実現できることが実証された．

組上げ型振付制作プロセスに基づくハウスダンスデザインシステム

大字諒，藤代一成

芸術科学会論文誌 (芸術科学会) 22 ( 3 ) 9:1 - 9:19 2023.09

Research paper (scientific journal), Joint Work, Last author, Corresponding author, Accepted, ISSN 1347-2267

昨今，多数の 3DCG 制作ソフトウェアの登場により，制作プロセスやそれを支援するユーザインタフェースが洗練され，3Dモーション制作の難度は大きく低下してきた．しかし，モーション制作の基本がキーフレーム操作であることに変わりはなく，依然として，複雑なダンスモーションはおろか，自然なモーションの制作にもかなりの技術が要求される．一方で，実際のダンスモーション制作プロセスはより単純である．特に，過去から現在までのダンス文化の集合体であるハウスダンスでは，ダンサーは各部位のモーションを要素として捉え，それらを連動させる組上げ型の制作プロセスを経ることで，様々な振付を制作してきた．そこで本研究では，様々なモーションと実際の振付制作で用いられる操作の関係性を明らかにし，多種多様なハウスダンスモーションの直観的制作を可能にするビジュアルプログラミング環境を提案する．提案システムでは，要素モーションに対する操作を表すノードをインタラクティブに接続することで振付制作プロセスを，さらにその制作した振付を順に接続することでシーケンス制作プロセスを再現する．実際に制作されたダンスモーションおよびシステムに対するユーザ評価から，モーションの自然さと提案環境の有用性が実証された.芸術科学会論文誌第22回論文賞受賞．

DVF：スケールの個人差を考慮した仮想シーン知覚像の半自動再現

星川　潤，藤代一成

芸術科学会論文誌 (芸術科学会) 22 ( 2 ) 2:1 - 2:11 2023.06

Research paper (scientific journal), Joint Work, Last author, Corresponding author, Accepted, ISSN 1347-2267

旅行先などで，印象的な情景を写真に収めた際，写真に記録された風景と自身が肉眼で捉えた風景との間に大きな違和感を覚えることがある．この現象は，カメラの投影モデルと人間の視知覚の特性の違いが原因のひとつであると考えられる．一般的なカメラが風景全体を平等に捉えるのに対し，人間は風景のなかで興味ある対象を部分的に強調しながら捉える．加えて，仮想シーンでは正確な大きさ知覚が現実シーンよりも難しいことが知られており，仮想シーン上で得た主観的な印象や感動を他者に効果的に伝えることは容易ではない．そこで本論文では，ユーザの注目部分を適度に拡大処理した画像を自動出力するシステムDigitus ViewFinder（DVF）を提案する．注目部分の特定にジェスチャインタフェースを用いることで，ユーザは没入感を損なわずに直観的で正確に範囲を選択できる．そして，試行とともにユーザの拡大率における個人差を学習することで，段階的に提案の精度が向上するサジェスティブインタフェースを実現する．実際にユーザ評価実験から，DVFシステムの有意性が確認された．

遊色効果再現のための三次元ボロノイ分割を用いたオパールのモデリング

橫田壮真，藤代一成

画像電子学会誌 (画像電子学会) 52 ( 1 ) 174 - 182 2023.01

Research paper (scientific journal), Joint Work, Last author, Accepted

宝石として用いられるオパールの多くは遊色効果とよばれる光学特性をもち，虹色の模様を発現する．ダイヤモンド，ルビー，サファイヤなどの宝石の大半は単結晶または多結晶であるのに対して，オパールは非晶質に分類され，複雑な内部構造をもつ．そのためオパールの内部構造を再現するには，計算資源の制約のもとで，遊色効果を再現するために必要十分な空間スケールでのモデリングが必要である．本研究は，オパールの内部構造を三次元ボロノイ分割を用いてモデリングすることで，結晶学に基づいた遊色効果の模様を再現する．さらに，オパールを構成する粒子の粒径や，粒子内に含まれる不純物による光の散乱係数及び吸収係数，回折格子の傾きといった4 種類のパラメタを用いて，オパールの汎用的なモデリングが可能であることを示す．

GPUを用いた多光源大域照明レンダリングにおける経路誘導の効率化

杉田俊平，橫田壮真，藤代一成

画像電子学会誌 (画像電子学会) 52 ( 1 ) 193 - 204 2023.01

Research paper (scientific journal), Joint Work, Last author, Accepted

大域照明レンダリングは, 高い写実性から映画分野を中心に利用されている. 主要手法の一つであるモンテカルロ・レイトレーシングにおいて, 出力画像は最終的な収束値から異なる画素を含んでおり, 収束までに多数のサンプル点が必要となる課題がある. ゆえに, サンプル当たりの分散低減効果を改善し, 少ないサンプル数で低分散な出力画像を生成する手法が必要とされている. 経路誘導は, 事前推定により求まる放射輝度分布に沿って重点的サンプリングを適用し, 効率的な経路構築を行うことで分散低減を実現する. しかし多光源シーンでは, 各光源からの寄与に伴う分布形状の複雑さから推定が進まず, 精度の低い学習分布による経路構築によりかえって分散が増大する可能性がある. 本論文では, 各光源からの寄与を考慮した光源選択を行い, 放射輝度分布の分布推定を改善することで, 多光源照明計算を効率化する手法を提案する. 提案手法をGPU プログラムとして実装したところ, 通常のパストレーシングと比較して最大で46.8 %の分散低減効果を示した.

ボリューム処理に基づく個別型実トルソーの開発と密着衣料デザインへの応用

山本高美，中山雅紀，坂元章，藤代一成

画像電子学会誌 (画像電子学会) 51 ( 4 ) 318 - 326 2022.10

Research paper (scientific journal), Joint Work, Last author, Accepted, ISSN 0285-9831

本資料論文は，画像電子学会英文誌掲載の論文「3D Distance Field-Based Apparel Modeling」に関連したものである．同論文で報告した先行研究では，まずボリューム表現された人体モデルに左右対称化・平滑化を施して，仮想トルソーを生成した．次に，ボリュームモデルから導出可能な3D ディスタンスフィールドに対して，しきい値処理を施し，詳細に計算されたゆとりをもった，女性用・男性用身頃原型，男性用ベストの衣料を開発した．本資料では，同論文の処理フローを拡張し，人体に最も近い形状の立体裁断用個別型実トルソーが開発できることを示す．はじめに，3D スキャナで得られたデータと同形状を得るためのしきい値の候補を抽出し，評価実験参加者20 名の3D計測データを用いて，対応のあるt 検定，2 要因分散分析を行なった結果，しきい値0.4（0: 体外，1：体内）の等値面が3D スキャナで得られた人体形状に最も近いことを示した．次に，多様なデザインの密着した衣料を立体裁断可能にするために，その等値面データを，発泡スチロール切削加工によって3D プリントして，立体裁断用個別型実トルソーを作成した．そして，その立体裁断用個別型実トルソーを用いて，身体に密着したドレスを立体裁断で製作し，試着評価により体型にフィットすることを確認した．

種数0サーフェスのヤコビアンフリーな変形シミュレーション

吉良俊亮，中山雅紀，藤代一成

芸術科学会論文誌 (芸術科学会) 21 ( 3 ) 146 - 156 2022.09

Research paper (scientific journal), Joint Work, Last author, Corresponding author, Accepted, ISSN 1347-2267

CG におけるオブジェクトの変形は，物質の多様な性質を表現するうえで，欠かすことのできない要素である．近年，映像作品の高精細化から，変形にもより高精細なものが求められるようになった．一般的な変形シミュレーション手法として，メッシュを用いた手法が挙げられるが，計算時間が多くかかることから，リアルタイム性を重視する場合，衝撃が加わった際にオブジェクト表面が波打つ様子などの細やかな変形表現は描画されない．一方，リアルタイム性を重視した変形シミュレーション手法として，変位マッピングを用いたアプローチが知られているが，この手法は二次元平面上に適用することを想定しているため，テクスチャ空間と実空間との間に非線形な関係が存在するオブジェクト表面に適用すると，ヤコビ行列を用いた座標変換による歪みを変形に生じさせてしまう．そこで，本論文では，射影によりテクスチャに格納した実空間座標を用いて計算することで，テクスチャ空間と実空間との間の歪みを解消した，変位マッピングによるヤコビアンフリーな変形シミュレーションを，種数0の任意オブジェクト表面において実現する手法を提案する．

Caps：深層学習を用いた書道作品における書体変換—篆書の文字認識と行書の作品生成—

二ノ宮梢平，藤代一成

芸術科学会論文誌 (芸術科学会) 21 ( 1 ) 11 - 22 2022.03

Research paper (scientific journal), Joint Work, Last author, Accepted, ISSN 1347-2267

書道は日本の伝統的な文化である一方で，書道展は経験者の間で完結している．その要因の一つとして，鑑賞が書道の習熟度合いに大きく依存していることが挙げられる．そこで，本研究では書道初心者を対象にした鑑賞支援として，篆書の文字を認識し，行書の書体へと変換するシステムCaps（Calligraphy appreciation system）を開発してきた．篆書の文字認識には，畳込みニューラルネットワークを用いた手法を導入した．漢字が偏旁冠脚といったパーツから構成されるという特徴を利用して，書道作品に用いられる難読文字の認識を実現する．これにより，少ないデータ数と少ないクラス分類で，より性能の高い文字認識が可能になる．一方，行書体への変換には，敵対的生成ネットワークを用いた手法を導入した．文字骨格に対する筆跡の付与を学習したモデルを用いて，任意の漢字による書道作品画像を生成する．ここで，筆画情報と筆順情報をもった骨格画像を用いることで，効果的な筆跡の学習を実現した．評価実験を通じて，上記の二種類の手法を実装した Caps により，書道作品に用いられる漢字の特定から書道作品画像の生成まで，直観的な操作に基づく鑑賞体験が可能になることを確認した．

サイクロープスの眼：直交配置マルチディスプレイを用いた裸眼立体映像生成のためのアナモルフォーシスの先鋭化

徳永敬太，長澤彦己，藤代一成

画像電子学会誌 (画像電子学会) 50 ( 4 ) 550 - 557 2021.11

Research paper (scientific journal), Joint Work, Accepted, ISSN 1348-0316

井阪らは，2 枚の汎用ディスプレイモニタを直交配置し，単眼性の錯視表現であるアナモルフォーシスにユーザの視線追跡を組み合わせることで運動視差を誘発し，裸眼立体映像を提示するシステムを開発した．しかし，小型のディスプレイモニタを利用する際に，このシステム上では両眼視差の影響が無視できず，ユーザの感じる立体感が低下する可能性がある．そこで本論文では，空間の構図を認識する両眼の貢献度の差異を特定し，アナモルフォーシスの効果を先鋭化する手法を提案する．利き目を追跡するよりも，両眼位置の適正な内分比の位置に「サイクロープスの眼」をおき，それに対してアナモルフォーシスを計算することで，効果の先鋭化と臨場感の向上が可能なことを実証した．さらに，折畳み式ディスプレイを搭載する商用ラップトップPC への提案手法の移植例も示す．

LinDA：漫画向けの建造物の背景線画半自動生成

中山雅紀，野村芽久美，藤代一成

芸術科学会論文誌 (芸術科学会) 20 ( 4 ) 210 - 218 2021.11

Research paper (scientific journal), Joint Work, Accepted, ISSN 1347-2267

近年，専門的なスキルのない作者でもデジタル漫画を描く機会が増えてきている．全コマに背景を描くには多大な時間を要するため，フリー素材の写真や線画を自作に利用することがある．しかし，汎用性を重視するフリー素材をそのまま漫画に挿入しても，素材の線画には作者自身の特徴をもたせられず，手描きオブジェクトに馴染まない場合がある．そこで本論文では，手癖が線分の角度に依存する事実に着目し，建造物のベクタ線画を手描き風の線画に半自動的にスタイル転写する手法を提案する．その手法を実装したシステム―LinDA (Line Drawing Artist) を用いた評価実験の結果，転写後の線画には描き手の手癖が反映されているという評価が得られた．また，提案手法により，作画時間短縮化および作業負荷軽減の効果も実現されることが分かった．

FIST: A Fast and Implicit Human Hand Model with Semi-Anatomical Structures

中田聖人，藤代一成

画像電子学会誌 (画像電子学会) 48 ( 4 ) 506 - 515 2019.10

Joint Work, Accepted

Human hands are particularly eye-catching parts from the first-person view, and realistic hand motion has been required in computer graphics (CG). An actual human hand consists of volumetric bones and various organs, such as tendons, muscles, and veins. However, a natural change in the appearance of the hand’s surface through the motion of its internal structures and an expression of the dynamism through the change can hardly be realized by most conventional CG models for an articulated human body because they just ‘skin’ the bones of a conceptual skeleton with a surface mesh. In this paper, a human hand model,called ‘Fast Implicit model with Semi-anatomical sTructures’ or ‘FIST’, is proposed to model the natural change in the appearance of the hand’s surface interactively. It can be modeled plausibly and efficiently by semi-anatomical modeling, where its bones are modeled anatomically while its tendons, muscles, skin, and veins are modeled artificially. Each of the organs is expressed with its own scalar function, and implicit modeling makes the change in the appearance of the hand’s surface reflected by the motions of these internal structures.

Naked-eye 3D imaging through optical illusion using L-shaped display surfaces

ISAKA Takeru, FUJISHIRO Issei

The Journal of The Institute of Image Information and Television Engineers (The Institute of Image Information and Television Engineers) 73 ( 1 ) J108 - J112 2019.01

Research paper (scientific journal), Joint Work, Accepted, ISSN 1342-6907

微細繊維が付加された糸を使用した布および織物の生成フレームワーク

池田泰成，都甲裕太朗，藤代一成

芸術科学会論文誌 (芸術科学会) 17 ( 5 ) 126 - 138 2018.12

Research paper (scientific journal), Joint Work, Accepted, ISSN 1347-2267

糸は織物や編物，衣服を構成するために必要であり，現実的なシーンを表現するために不可欠な素材である．これまでに開発された糸の生成手法は，主としてボリュームベースと繊維ベースの二種類に分類できる．近年の先進的な手法により，CG における糸の表現力は劇的に向上し，なおかつその生成に必要なコストも減少した．しかし，糸の周囲に生える毛羽立ちや装飾を目的とした糸の生成プロセスは，未だに挑戦的な課題である．特に，表面の毛羽立ちが独特な形状をもつパイル織物や，装飾を施した編物を制作する際に使用されるシェニール糸は，タオルや車のシート地，衣服など生活のあらゆる場所で使用される一般的な素材であるにもかかわらず，その構造の複雑性からモデリングが困難である．加えて，既存手法では一本の糸の生成プロセスに注目しているが，その糸を使用した大規模な織物や布の生成フレームワークについては，筆者らの知る限り提案されていない．これらの課題を解決するため，本論文では既存のフレームワークを拡張することで微細繊維をもつ糸の生成に対応するとともに，この糸から自動的に織物や布を生成する手法を提案する．芸術科学会論文誌第17回論文賞受賞．

Resource-Aware Rendering for Laser Plasma Scanning 3D Display Devices Using Surface Descriptors

NAKATANI Ayaka, FUJISHIRO Issei, ISHIKAWA Hiroyo, SAITO Hideo

Transactions of the Virtual Reality Society of Japan (VRSJ) 17 ( 3 ) 419 - 428 2012.12

Research paper (scientific journal), Joint Work, Accepted, ISSN 1344-011X

Laser-Plasma Scanning 3D Display (LPSD) is one of the most advanced volume scanning display devices, and plots a unicursal series of illuminants freely in the air. Though the LPSD device has been repeatedly upgraded, even the latest version is only capable of plotting an object at a rate of 5,000 illuminants per second, purely due to the hardware limitation. If we plotted illuminants at a regular interval with a constant brightness, it might possibly lead to loss of geometry and/or surface texture of the displayed object. This paper, therefore, proposes a software-based approach to ameliorate this problem, which controls the brightness and density of plotted illuminants in accordance with existing surface descriptors, to convey salient features of 3D shapes with even a limited number of illuminants.

Interactive simulation of whirlwind using grid and particles

NAKAJIMA Satoshi, FUJISHIRO Issei

The Journal of the Society for Art and Science (The Society for Art and Science) 11 ( 4 ) 157 - 165 2012.12

Research paper (scientific journal), Joint Work, Accepted, ISSN 1347-2267

In this paper, we present an interactive approach to visual simulation of whirlwind using grid and particles. Higher-resolution simulation can be carried out efficiently by perturbing air flow computed on a rough grid with small-scale turbulence. The grid-based simulation first provides a primary whirlwind flow field through modeling its underlying heat convection. Then, the particle-based simulation computes the transport energy of turbulence based on a two-equation k-ε model, which allows us to capture the turbulence details. The dynamism of whirlwind is conveyed effectively by the interaction with rigid and deformable bodies, such as flag, branch and paper, placed on interactively-controllable trajectories. In addition, a simplified variant of particle-based volume rendering is utilized to delineate changes in the translucency of whirlwind, which reflects the amount of sand particles stirred up from the ground.

Light Source Placement Design for TopologicallyEnhanced Volume Rendering

TAKESHIMA Yuriko, NARAOKA Ryota, FUJISHIRO Issei, TAKAHASHI Shigeo

The Journal of the Institute of Image Electronics Engineers of Japan (IIEEJ) 38 ( 4 ) 459 - 470 2009.07

Research paper (scientific journal), Joint Work, Accepted, ISSN 0285-9831

In order for volume rendering to convey the features of a given volume dataset effectively, it is required to design the illumination environment with which we can provide enriched depth cues for the rendered features, as well as to specify the transfer functions which emphasize the features, to locate the viewpoint in such a way as to minimize the occlusion artifacts among the projected features. In this paper, we strive to extend the conventional illumination entropy-based framework for surface models to come up with a novel method for finding an optimal location of light source for further enhancing differential topology features embedded within the volume. The feasibility of the proposed method is empirically proven through several experiments with practical datasets for the case with a single parallel light source. The extensibility of the method to the problem of multi light sources placement is also discussed.

Modeling audience NPC's diversity for enhanced illusionary sociality in collective VR concert experiences

Takehiro Ishinuki, Issei Fujishiro

ICAT-EGVE 2025 - International Conference on Artificial Reality and Telexistence and Eurographics Symposium on Virtual Environments (Eurographics) 2025.12

Research paper (international conference proceedings), Joint Work, Last author, Corresponding author, Accepted, ISSN 1727-530X

Virtual reality (VR) live performances offer a novel style of experience through the deployment of three-dimensional cartoonlike performers and through spatiotemporally asynchronous participation. However, such experiences often lack the presence and atmospheric richness of physical live concerts. To address this gap, prior research has proposed audience non-player characters (NPCs) that emulate the collective characteristics of real-world audiences to enhance viewer engagement. In this study, we extend existing approaches by incorporating individual motion diversity to synthesize audience NPCs that form a heterogeneous and lifelike crowd. In addition to collective characteristics, such as music-driven motion changes and gradual synchronization, our modeling approach introduces agent-level diversity, even within the same motion categories. To assess the psychological impact of the proposed method, we developed a VR concert scenario featuring approximately 1,500 audience NPCs and conducted an empirical evaluation of the user experience. The findings indicate that enhanced motion heterogeneity can increase a viewer's sense of presence, engagement, perceived unity, and co-existence in a VR concert environment.

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Identification of leading lines in artworks based on topological analysis of saliency maps

Fuminori Shibasaki, Issei Fujishiro

Proceedings of 2025 IEEE 18th Pacific Visualization Conference (PacificVis) (IEEE Computer Society) 369 - 374 2025.04

Research paper (international conference proceedings), Joint Work, Last author, Corresponding author, Accepted, ISSN 21658765

A key compositional technique, leading lines guide the observer's gaze across visual scenes. This study presents a novel approach to the visual analysis of leading lines in artworks by applying discrete Morse theory to saliency maps refined through persistent homology. The saliency map’s gradient field is abstracted into a structured representation using the maximum graph, enabling the identification of both explicit and implicit leading lines. To enhance the analysis, texture gradient cues are incorporated to embed depth information into the saliency map. Our visual analysis system also features semiautomatic thresholding and tools to depict the direction of visual guidance. An experimental study with participants from an art university validated the system’s feasibility by analyzing variousWestern paintings. This research contributes to the field of digital and public humanities and computational art analysis by offering an environment in which to explore visual composition.

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3D fluid shape control by direct manipulation

Kohei Aoyama, Yuto Hayakawa, Issei Fujishiro

Advances in Visual Computing—19th International Symposium, ISVC 2024, Lake Tahoe, NV, USA, October 21–23, 2024, Proceedings, Part I (Springer LNCS) 16045 99 - 110 2025.01

Research paper (international conference proceedings), Joint Work, Last author, Corresponding author, Accepted, ISSN 03029743

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An efficient and smooth volume shell mapping by nonlinear ray traversal of hierarchical structures

Mayuka Kuwana, Issei Fujishiro

SIGGRAPH Asia 2024 Technical Communications (ACM) 37:1 - 37:4 2024.12

Research paper (international conference proceedings), Joint Work, Last author, Corresponding author, Accepted

Shell mapping is a method of representing microstructures on surfaces by mapping a three-dimensional texture space bijectively into a shell space. This paper introduces a volumetric texture to the texture space for the purpose of representing implicit surfaces and translucent materials. However, conventional approaches often generate artifacts at the boundaries of neighboring tetrahedra due to piecewise-linear approximate mapping. To achieve smooth mapping, we present an approach of mapping rays nonlinearly into the texture space, and we also address efficient sampling by using hierarchical volumetric textures.

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Synthesis of enthusiastic collective audience NPCs in VR live concerts

Takehiro Ishinuki, Issei Fujishiro

Proceedings of Cyberworlds 2024 (IEEE CPS) 33 - 40 2024.10

Research paper (international conference proceedings), Last author, Corresponding author, Accepted, ISSN 2642-3596

Virtual reality (VR) live concerts have recently attracted much attention because of their various possibilities for future music entertainment in cyberworlds. However, it has been reported that current VR live experiences do not reach the levels of enthusiasm observed at actual live concerts, and achieving a sense of enthusiasm in VR live concerts is a challenge to offer enough engagement. According to studies in the field of social psychology, psychological interactions with the surrounding audience are crucial to generating a sense of enthusiasm at actual live events. In response, this paper proposes a method for synthesizing enthusiastic collective non-player characters (NPCs) for VR live concerts. The proposed method computes the psychological interactions among the audience members, including the viewer, according to two psychological parameters. The synthesized audience NPCs are affected by both the music and their psychological interactions according to the surrounding audience, including the viewer, and they exhibit the features of an enthusiastic collective crowd. As such, an empirical study was conducted to explore the psychological influence of the proposed audience NPCs on VR live experiences. The results indicate that the proposed method could give the impression of an enthusiastic crowd at VR live experiences. In addition, it was suggested that social sensations between the audience NPCs and the viewer should be enhanced to increase the level of enthusiasm portrayed during VR live experiences. What was further suggested is the need for a certain degree of individual difference and diversity in appearance and motions for a natural collective audience.

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STMA: A fast visual field defect assessment method using quadtree and head mounted display

Chao Ge, Zhenyang Zhu, Kenji Kashiwagi, Masahiro Toyoura, Kentaro Go, Issei Fujishiro, Xiaoyang Mao

Proceedings of NICOGRAPH International 2024 (SAS) 2024.06

Research paper (international conference proceedings), Accepted

Individuals with eye diseases that cause optic nerve damage, such as glaucoma, suffer from visual field defects (VFDs), rendering the assessment of VFDs an essential step in medical treatment. In existing studies, various methods have been proposed for VFD area inspections. However, these methods present several problems, including long inspection times and the need to maintain a posture for extended periods, potentially placing significant physical and psychological burdens on patients and affecting the accuracy of the inspection result. Moreover, loose eye fixation constraints also decrease the reliability of the result. In response, we herein propose a novel approach for a fast VFD test, facilitated by the quadtree algorithm. To overcome the physical burden caused by posture constraints related to the testing area requirements and location of the stimulus, the proposed VFD test is implemented on a head-mounted display with a built-in eye tracker. To improve the accuracy of the inspection result further, variously sized noise fields were adopted as the stimuli shown to the examinees. In addition, to validate the performance of the proposed method, a mock experiment was conducted in this study, which involved volunteers with normal vision. The experimental results indicate that the proposed method demonstrates a competitive advantage in perimetric time compared to current state-of-the-art methods, and it exhibits advantages in terms of both accuracy and user comfort.

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Frame-break: Enhancing stereoscopic effect of an anamorphosis based naked-eye 3D imaging system

Keita Tokunaga, Issei Fujishiro

Proceedings of The 8th IIEEJ International Conference on Image Electronics and Visual Computing (IEVC 2024) (IIEEJ) 2024.03

Research paper (international conference proceedings), Joint Work, Last author, Corresponding author, Accepted

VigNet: Semiautomatic generation of vignette illustrations from video

Mayu Namai, Issei Fujishiro

Proceedings of The 8th IIEEJ International Conference on Image Electronics and Visual Computing (IEVC 2024) (IIEEJ) 2024.03

Research paper (international conference proceedings), Joint Work, Last author, Corresponding author, Accepted

HomeShelf: Cultivating Individual Relationships with Digital Contents

Sota Tanaka, Issei Fujishiro

2023 28th Asia Pacific Conference on Communications (APCC) (IEEE) 369 - 374 2023.11

Research paper (international conference proceedings), Joint Work, Last author, Accepted

The digitization of material objects is rapidly advancing, progressively offering people an unprecedented level of convenience and accessibility. However, studies have shown that people feel a lesser attachment to digital contents than to material objects. In this paper, we focus on shelves, thought to be hubs for cultivating individual relationships with material objects in daily life. We thus propose HomeShelf, an application that accelerates interactions with digital contents and fosters deeper attachments to them. Further, we discuss the features to be added using new technologies and the impact on digitized material objects.

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Topological analysis and approximate identification of leading lines in artworks based on discrete Morse theory

Fumimori Shibasaki, Issei Fujishiro

Proceedings of IEEE VIS 2023 (IEEE Computer Society) 6 - 10 2023.10

Research paper (international conference proceedings), Joint Work, Last author, Corresponding author, Accepted

Accomplished artists often incorporate leading lines into their compositions to guide the observer’s attention. Although saliency maps are typically employed to locate attractive regions in still images, such scalar features do not express the trajectory of an observer’s gaze. In this study, we propose a method for the visual analysis and approximate identification of leading lines based on maximum graphs, sparse subsets of Morse–Smale complexes, extracted from saliency maps. We provide empirical evidence substantiating the feasibility of our method through a comparison with actual observers’ eye tracking results. Further, we investigate the limitations of our approach by employing it to analyze a variety of artworks with diverse styles.

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Metamorphopsia inspection system based on relevance feedback

Zhenyang Zhu, Masahiro Toyoura, Kentaro Go, Issei Fujishiro, Xiaoyang Mao

2023 IEEE International Conference on Systems, Man, and Cybernetics (SMC) (IEEE) 4667 - 4674 2023.10

Research paper (international conference proceedings), Joint Work, Accepted, ISSN 1062922X

People with metamorphopsia suffer from perceiving things in a distorted way. Various methods for examining metamorphopsia have been suggested in the current literature, with the most advanced techniques demonstrating the ability to yield quantitative measurements. However, these cutting-edge methods necessitate extended examination durations and impose challenging manipulations on patients. In this study, our objective is to enhance the time efficiency of the inspection process and alleviate the burden placed on the user. We propose a novel user-friendly quantitative inspection system which utilizes interactive reinforcement learning. Instead of having users directly operate the system, we ask them to evaluate the stimuli generated by the system. Based on their evaluations, the system gradually refines the deformation map representing the distortion perceived by the user. The reinforcement learning scheme is implemented using relevance feedback approach based on optimum-path forest classifier. To evaluate the effectiveness of the proposed system, subjective evaluation experiments involving simulated and real metamorphopsia participants were conducted in this study. The experimental findings reveal that, when compared to the state-of-the-art method, our proposed system yields comparable inspection out-comes while significantly reducing both the inspection duration and the mental workload.

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Virtual manipulation of cultural assets: An initial case study with single-joint articulated models

Sakura Shinji, Issei Fujishiro

ACM SIGGRAPH 2023 Posters Proceedings (ACM) 26:1 - 26:2 2023.08

Research paper (international conference proceedings), Joint Work, Last author, Accepted

Virtual space can eliminate the physical constraints of real space. Three-dimensional (3D) digital twins enable us to experience manipulation of cultural assets that are inaccessible in real space. However, most 3D models obtained using current reconstruction techniques are static; they cannot be manipulated dynamically. In this study, we reproduce a dynamic 3D model of a simple articulated object with a rotating joint from a static point cloud only with reference to a video of the motion and a manually added rotation axis. The reconstructed actual cultural asset is used for first-person experiences in an augmented reality environment.

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Clustering, universalities, and evolutionary schema design

Issei Fujishiro, Naoko Sawada, Makoto Uemura

CEUR Workshop Proceedings 3379 2023.03

Joint Work, Lead author, Corresponding author, Accepted, ISSN 1613-0073

Exploring data features using visual clustering is a significant challenge of big data analytics. In this vision paper, we focus primarily on the relationship among visual data clustering, the discovery of universalities, and the design of an evolutionary database to propose an inter-disciplinary method for scientific data management. The feasibility of the proposed method is empirically proven through application to a practical visual analytics environment for time-varying multi-dimensional datasets of blazar observations.

CC-Glasses: Color communication support for people with color vision deficiency using augmented reality and deep learning

Zhenyang Zhu, Jiyi Li, Ying Tang, Kentaro Go, Masahiro Toyoura, Kenji Kashiwagi, Issei Fujishiro, Xiaoyang Mao:

Proceedings of the Augmented Humans International Conference 2023 (ACM) 190 - 199 2023.03

Research paper (international conference proceedings), Joint Work, Accepted

People who suffer from color vision deficiency (CVD) can face difficulties when communicating with others by failing to identify target objects referred by their color names. While most existing studies on CVD compensation have focused on the issue of color contrast loss. Although there are approaches can provide clues of color name to users, these techniques either require training, or cannot protect users' privacy, i.e., the fact of having CVD. In this paper, based on augmented reality (AR) and deep learning technologies, we propose a novel system to provide supporting information to users affected by CVD for color communication assistance. The state-of-the-art deep neural network (DNN) model for referring segmentation (RS) is adopted to generate supporting information, and AR glasses are utilized for information presentation. To improve the performance of the proposed system further, a new dataset is constructed based on a novel concept called Color-Object Noun Pair. The results of evaluation experiments show that the new dataset can enhance the performance of the adopted DNN model, and the proposed system can help users affected by CVD successfully identify target objects by their color names.

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A study on contextual task performance of simulated homonymous hemianopia patients with computational glasses-based compensation

Chao Ge, Zhenyang Zhu, Keisuke Ichinose, Issei Fujishiro, Masahiro Toyoura, Kentaro Go, Kenji Kashiwagi, Xiaoyang Mao

Proceedings of ACM VRCAI 2022 (ACM) ( 34 ) 1 - 8 2022.12

Accepted

People with Homonymous Hemianopia (HH) suffer from losing ipsilateral half side of visual field in both eyes, which results in failing to obtain visual information in the lost field. Making using of the remaining of the visual field, the state-of-the-art studies proposed Overlaid Overview Window (OOW) and Edge Indicator (EI) on the basis of Augmented-Reality (AR) glasses for compensation. However, experiments conducted in these studies investigate user performance with tasks involving events in lost field or remaining field singly. On the other hand, both studies recruited normal individuals for mock experiment, while their way to simulate HH, which requiring the participants to fix their view angles, were not practical to real HH patients. In this study, we conduct a contextual information experiment to investigate the user performance involving in the task requiring the information across both the visible and invisible sides of HH, with the compensation of OOW and Flicker-based EI (FEI). At the same time, we also recruit volunteers with normal vision for mock experiment, while the participants in our study are allowed to move their gaze freely, because we simulate the invisible field of HH on AR glasses with eye tracking. The experiment results showed that OOW is better for the task that related to move something from the remaining FoV to the lost FoV, while FEI is better for moving something from the lost FoV to the remaining FoV.

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Affine-transformed ray alignment for fast ray traversal

Yuki Nishidate, Issei Fujishiro

ACM SIGGRAPH Asia 2022 Technical Communications Proceedings (ACM) 13:1 - 13:4 2022.12

Research paper (international conference proceedings), Joint Work, Last author, Accepted

In recent years, ray tracing has begun to be used for real-time rendering. However, the number of rays that can be emitted in real time is limited due to the high time complexity of ray tracing. In this paper, we propose affine-transformed ray alignment as a novel method of reducing time complexity. Using affine transformations, the proposed method aligns multiple rays to form a single ray while maintaining the intersection points obtained from the scene, thereby speeding up ray tracing without introducing errors. We also propose application of our method to the problems of primary ray traversal, stereo rendering, and multi-frame rendering and empirically prove that time complexity can be reduced by these simple implementations.

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Anime-like motion transfer with optimal viewpoints

Yui Koroku, Issei Fujishiro

ACM SIGGRAPH Asia 2022 Posters Proceedings (ACM) 8:1 - 8:2 2022.12

Research paper (international conference proceedings), Joint Work, Last author, Accepted

In 3D character animation, the frame rate is often reduced to mimic hand-drawn animations, like anime (Japanese animation). However, anime with a low frame rate differs from real motions because it omits excessive movements and emphasizes speed by expressing motions with a small number of impressive poses. It is difficult to reproduce such motions only by downsampling mocap data. Thus, in this poster, we propose a method for converting mocap data into anime-like 2D motions by respecting production site techniques. The proposed method evaluates the characteristics of motion data using the time distributions of speeds and pose areas to select an appropriate sequence of viewpoints and extract effective poses for each viewpoint.

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DVF: Toward semiautomatic composition of perceptual images of a virtual scene through hand gesture interface

Jun Hoshikawa, Issei Fujishiro

Proceedings of Cyberworlds 2022 (IEEE CPS) 169 - 170 2022.09

Research paper (international conference proceedings), Joint Work, Last author, Corresponding author, Accepted

Human beings perceive scenes by enlarging an area of interest (AOI), whereas an ordinal camera captures the entire scene evenly. Therefore, it is not easy to share subjective impressions with others effectively only by sharing normal photos. Such challenges exist in cyberworlds as well. In this study, we design Digitus View Finder (DVF), a system that automatically outputs images close to the scenes a user perceives. A preliminary user study indicated that the DVF
would be able to estimate a plausible scale factor of the AOI as a function of three parameters: the number of subjects in the AOI, the distance to the subjects, and a personal difference as a correction term.

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FORSETI: A provenance-aware visual analysis environment for the lifecycle management of e-autopsy reports

Baoqing Wang, Noboru Adachi, Issei Fujishiro

CEUR Workshop Proceedings 3135 2022.03

Research paper (international conference proceedings), Last author, Corresponding author, Accepted, ISSN 16130073

Autopsy reports are imperative for both medical and legal science. Medical examiners (MEs) and diagnostic radiologists (DRs) cross-reference autopsy findings, while judicial personnel derive legal documents. In a prior study, we proposed a visual analysis system named FORSETI (forensic autopsy system for e-court instruments) with x-LMML (extended legal medicine markup language) for MEs and DRs to author and review e-autopsy reports. In this paper, we outline our extended work in progress to introduce a provenance infrastructure for forensic data accountability to FORSETI, which can be characterized by two technical essences. The first is a provenance management mechanism that combines the forensic autopsy workflow management system (FAWfMS) and lmmlgit (a version control system for x-LMML files), allowing a large amount of provenance information about e-autopsy reports and their documented autopsy processes to be individually parsed. The second is authority management, which ensures the confidentiality of e-autopsy reports by deploying strict syntax-guided workflow controls and a custom-tailored tool.

SpiCa: Stereoscopic effect design with 3D pottery wheel-type transparent canvas

Riwano Ikeda, Issei Fujishiro

ACM SIGGRAPH Asia 2021 Technical Communications (ACM) 14:1 - 14:4 2021.12

Research paper (international conference proceedings), Joint Work, Last author, Accepted

Flow effects such as flames, smoke, and liquids play an important role in activating illustrations, but drawing these effects requires artistic expertise as well as a great deal of effort. In this paper, we propose a method for adding stereoscopic effects to character illustrations using various shapes of 3D pottery wheel-type transparent canvases. One approach to designing a flow effect to decorate a character relies on simple curved geometry to beautify its flowin an organized composition.We extend this approach to present a drawing system—SpiCa (spinning canvas), which enables users to use rotatable transparent canvases to design 3D flow effects. User evaluations show that users can create such effects more easily and effectively and reduce their workload with SpiCa in comparison with an existing 2D illustration tool.

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Illumination-aware digital image compositing for full-length human figures

Masaru Ohkawara, Issei Fujishiro

Proceedings of Cyberworlds 2021 (IEEE) 17 - 24 2021.09

Research paper (international conference proceedings), Joint Work, Accepted

In this paper, a novel compositor to realize illumination-aware digital image compositing is proposed. Digital image compositing is a technique to re-synthesize a single image from multiple visual elements. Assembling separated visual elements leads to highly efficient content creation at risk of losing visual coherence. Visual coherence has two types: positional and illumination. Compositing while maintaining illumination coherence is considered a challenging task, because light transport information is needed to reproduce global illumination effects—color bleeding, soft shadows, caustics, and so on. The pipeline of the proposed compositor incorporates shape reconstruction, as well as global illumination simulation and relighting; thus, the compositor can reproduce background-to-foreground color bleeding and soft shadows. It is empirically evaluated that the proposed compositor compares favorably with rendering both in terms of quality and speed. Because it is in principle impossible to render the foreground and background elements together, the proposed compositor is inevitably selected to generate images with the two types of visual coherence. This leads to efficient construction of photorealistic cyberworlds.

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THEMIS: Context-sensitive similarity analysis for wound imagery using mathematical model of meaning

Masaru Ohkawara, Issei FujishiroYume Asayama, Baoqing Wang, Masanori Nakayama, Hideki Shojo, Noboru Adachi, Yasushi Kiyoki, Issei Fujishiro

Proceedings of Cyberworlds 2021 (IEEE) 129 - 132 2021.09

Research paper (international conference proceedings), Joint Work, Accepted

Even when generated with the same weapon, a　wound's appearance would be affected by its use and the assaulter’s physique. In contrast, even if wounds look similar in shape and/or color, they could have a different wounding history. In this work, we strive to extract the features of shape and color from a given wound image and build on the mathematical model of meaning to create the associated semantics of the criminal act. We demonstrate that a system called THEMIS (theoretical estimation of the meaning of insults) provides a context-sensitive visual similarity analysis for wound imagery in computational forensics. The THEMIS system can help forensic doctors and e-court stakeholders potentially determine important aspects of a case through a comparison with wounds of corpses in past cases, in a way that is not currently possible.

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Eye-tracker-free compensation for metamorphopsia

Masaru Ohkawara, Issei FujishiroKatsuhito Moritake, Zhenyang Zhu, Masahiro Toyoura, Kentaro Go, Kenji Kashiwagi, Issei Fujishiro, Xiaoyang Mao

Proceedings of Cyberworlds 2021 (IEEE) 78 - 84 2021.09

Research paper (international conference proceedings), Joint Work, Accepted

Metamorphopsia is a symptom caused by abnormalities in the retina, and people with metamorphopsia experience distortions in their field of view. To compensate for this disorder, computer-based distortion assessment and compensation methods have been proposed. In the state-of-theart method, compensation is carried out by dynamically deforming the image with a manipulation map, which is bound to the symptom of an individual user with metamorphopsia, according to the user’s gaze data captured by an eye tracker. However, this method suffers from the instability and inaccuracy of the eye tracker, which leads to a poor compensation effect. In this paper, we propose a novel method for metamorphopsia compensation without using an eye tracker. The proposed method generates a compensation image by simultaneously applying multiple manipulation maps to the input image. To evaluate the effectiveness of the proposed method, a preliminary subjective experiment using a reading task and involving 10 participants with normal vision was conducted. The evaluation results show that the proposed method can compensate for visual distortion during reading tasks.

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3D distance field-based apparel modeling

Masanori Nakayama, Takami Yamamoto, Issei Fujishiro

Proceedings of IEVC 2021 (IIEEJ) 2021.09

Research paper (international conference proceedings), Joint Work, Accepted

This study aims to effectively design an apparel item by converting a polygon model of the human body obtained through 3D scan into a volume model. From the model, we can quickly generate a curved surface that retains a constant distance from the body surface, and thus design clothing material that ensures accurate “allowance” by defining the distance field for the body surface. Furthermore, by drawing a design line on the curved surface, the pattern required for actual sewing can be designed in three dimensions. A dynamics simulation is applied to smooth the curvatures so that the desired flat surface pattern can finally be obtained. As a result of actually sewing the virtually designed pattern and try-on, it was proven that we can generate clothes with the appropriate allowance and proportions.

Adjusting control parameters of topology-accentuated transfer functions for volume raycasting

Yuriko Takeshima, Shigeo Takahashi, Issei Fujishiro

Topological Methods in Data Analysis and Visualization V: Theory, Algorithms, and Applications (Springer International Publishing) 71 - 86 2020.12

Research paper (international conference proceedings), Joint Work, Accepted

The design of automatic transfer functions for volume rendering is a perennial problem in volume visualization. Over the last three decades, a variety of design methodologies have been proposed. However, sensitive adjustment of related control parameters remains entrusted to users, because rendering conditions,such as the thickness of emphasized subvolumes in the ray direction and the size of a target dataset, differ on a case-by-case basis. Our group previously proposed one-dimensional transfer functions to accentuate topological changes in the scalar field of the target dataset. However, the method forces us to determine the actual control parameter values for the transfer functions in an empirical manner. In this paper, we propose a supplementary mechanism with which to judiciously define an appropriate profile of the opacity values. More specifically, the height and width of the hat opacity transfer functions that accentuate feature isosurfaces are determined according to the number of voxels belonging to the relevant topologically equivalent scalar field interval. The feasibility of the proposed method is evaluated by its application to five kinds of volume datasets.

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Using an eye tracking device to discriminate different symptoms in glaucoma

Lina Chen, Kentaro Go, Yuichiro Kinoshita, Kenji Kashiwagi, Masahiro Toyoura, Issei Fujishiro , Xiaoyang Mao

Proceedings of Cyberworlds 2020 141 - 144 2020.09

Research paper (international conference proceedings), Joint Work, Accepted

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Different eye movement patterns on simulated visual field defects in a video-watching task

Changtong Mao, Kentaro Go, Jianjun Li, Yuichiro Kinoshita, Kenji Kashiwagi, Masahiro Toyoura, Issei Fujishiro, Xiaoyang Mao

Proceedings of Cyberworlds 2020 153 - 156 2020.09

Research paper (international conference proceedings), Joint Work, Accepted

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Automatic generation of 3D natural anime-like non-player characters with machine learning

Ruizhe Li, Masanori Nakayama, Issei Fujishiro

Proceedings of Cyberworlds 2020 (IEEE) 110 - 116 2020.09

Research paper (international conference proceedings), Joint Work, Last author, Accepted

In role-playing games, creators always use specific models to generate non-player characters (NPCs). The prefabricated models are materialized in the scenes, and if more NPCs are included than character models prepared, the players may easily find many NPCs with similar appearances,which makes the scenes unnatural. In this paper, we propose a novel system for generating a rich variety of 3D anime-like NPCs in real time to make the scenes look more natural. We combine a proprietary character customization system with machine learning, where the customizing parameters are treated as feature vectors input in the neural network. The parameters are trained to avoid generating bad-looking models. We demonstrate that the proposed system can generate a natural school classroom scene with a variety of good-looking female student NPCs in a uniform.

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Visual field loss compensation for homonymous hemianopia patients using edge indicator

Keisuke Ichinose, Xi Zhao, Issei Fujishiro, Masahiro Toyoura, Kenji Kashiwagi, Kentaro Go, Xiaoyang Mao

Proceedings of Cyberworlds 2020 79 - 85 2020.09

Research paper (international conference proceedings), Accepted

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rewind: Visual exploration of web video viewing history for self-reflection

Takuya Suga, Genki Nagasawa, Masanori Nakayama,Issei Fujishiro

Proceedings of the Second Leipzig Symposium on Visualization in Applications (LEVIA19) 2019.11

Joint Work

Due to the rise in popularity of video sharing websites, video streaming services, and social networking services,people daily watch many videos on the web. However, viewers do not commonly access their video viewing history for the purpose of self-reflection and self-representation. A previous research addressed the issue of creating visual mementos, or visualizations to be kept as reminders of life experiences from personal digital data. As a new application of the research, in this paper we present a system named rewind, through which users can create visual mementos of their web video viewing experiences to reminisce about and share. The system rewind provides two kinds of visualizations: MapView (2D) and TubeView (3D), both of which are intended to visualize the YouTube video viewing history of a single user by giving plausible meanings to the size and position of thumbnails and directed links between them. These visualizations remind users of their interests and viewing preferences hidden in the watch history. The user interface of rewind is designed with designated visual exploration functions according to Shneiderman’s Visual Information Seeking Mantra.We also employed an anamorphosis-based, naked-eye 3D display technique in order for TubeView to build an immersive environment for facilitating self-reflection. In addition, the system rewind provides the functionalities that are necessary in a visual memento creation tool to express subjectivity toward the past and to share visual mementos with others while hiding sensitive information.

Computational alleviation of homonymous visual field defect with OST-HMD: The effect of size and position of overlaid overview window,

Xi Zhao, Kentaro Go, Kenji Kashiwagi, Masahiro Toyoura, Xiaoyang Mao, Issei Fujishiro

Proceedings of Cyberworlds 2019 2019.10

Joint Work

Visual field defect (VFD) refers to a symptom in which a patient loses part of his/her field of view (FoV). Medical therapy can halt the progression of VFD, but complete recovery is impossible. In this paper, we propose a computational method for alleviating the restricted FoV with an optical see-through headmounted display (OST-HMD), where an overview scene captured by the installed camera is overlaid on the persisting FoV. Because the overview window occludes with the real world scene, there is a trade-off between the augmented contextual information and the local unscreened information. We hypothesized that such a trade-off can be resolved by taking into consideration the size of the overview window and its displacement from the center of the unimpaired FoV. We therefore conducted an empirical evaluation through a Whac-A-Mole type of task with ten VFDimitative subjects, where three sizes of an overview window with a fixed aspect ratio and seven positions in terms of elevation and azimuth were used combinatorially on an OST-HMD to find the best size and position of the overview window. It was statistically proven that for left-sided homonymous VFD-imitative subjects,the performance of the task was better when the medium-sized overview window was placed in the lower right position. The obtained result can legitimate default setting for the proposed VFD alleviation method.

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Visual assessment of distorted view with metamorphopsia patient by interactive line manipulation

Hiromichi Ichige, Masahiro Toyoura, Kentaro Go, Kenji Kashiwagi,Issei Fujishiro , Xiaoyang Mao

Proceedings of Cyberworlds 2019 2019.10

Joint Work

The number of individuals with Age-related Macular Degeneration(AMD) is rapidly increasing.One of the main symptoms of AMD is ‟metamorphopsia,” or distorted vision, which not only makes it difficult for individuals with AMD to do detailed-oriented tasks but also makes sufferers more vulnerable to certain risks in day-to-day life. Traditional clinical approaches to assess metamorphopsia have lacked mechanisms for quantifying the degree of distortion in space,making it impossible to know exactly how individuals with the condition see things. This paper proposes a new method for quantifying distortion in space and visualizing AMD patients’ distorted views via line manipulation. By visualizing the distorted views stemming from metamorphopsia, the method gives doctors and others an intuitive picture of how patients see the world and thereby enables a broad range of options for treatment and support.

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Visual simulation of washing denim with fiberlevel details

Yutaro Togo, Yasunari Ikeda, Issei Fujishiro

Proceedings of the 6th IIEEJ International Workshop on Image Electronics and Visual Computing (IEVC2019 ) ( IIEEJ) 2019.08

Joint Work, Corresponding author

When expressing the temporal change of finely structured clothes, deterioration is an imperative factor of visual simulation. Considering the complexity of their microstructures, a simple and easy way to damage finely structured clothes is required. This paper presents a novel method for modeling clothes with fiber-level details and showing their damages on a ray-tracing basis. Our particular focus is placed on washed jeans, where representative kinds of local deterioration, including cutting of fiber and color fading, affect the entire appearance of the clothes. The plausibility of the proposed method was empirically proven with several modeling and rendering experiments.

User experience design in virtual learning environment for complex projective geometry

Atsushi Miyazawa, Masanori Nakayama, Issei Fujishiro

Proceedings of the 6th IIEEJ International Workshop on Image Electronics and Visual Computing (IEVC2019 ) (IIEEJ) 2019.08

Joint Work, Last author

Spectrail: Visual analytics for compositional process with sound analysis and synthesis

Yuriko Takakura, Issei Fujishiro

Proceedings of ICMC2019 2019.06

Research paper (international conference proceedings), Joint Work, Last author, Corresponding author

Collaborative visual analysis with multi-level information sharing using a wall-size display and see-through HMDs

Tianchen Sun, Yucong Chris Ye, Issei Fujishiro, Kwan-Liu

Proceedings of IEEE PaciﬁcVis 2019 (IEEE Computer Society) 11 - 20 2019.04

Research paper (international conference proceedings), Joint Work

© 2019 IEEE. Solving complex data analysis problems can often benefit a collaborative effort. For synchronous co-located collaboration, a well-recognized challenge is to deliver different contents to people with different privileges and different responsibilities. This challenge is becoming more obvious with the use of a shared display space such as a wall-size display. In particular, scenarios often arise that a privileged participant needs to access sensitive information that other participants are not permitted to view. This is nearly impossible to achieve with only a single display. As a result, it becomes clear that additional devices are needed to provide some of the participants the capability to access and manage certain information in a private space. In this work, we investigate incorporating optical see-through head-mounted displays (OST-HMDs) with a wall-size display to deliver sensitive information in a synchronous co-located, collaborative setting. With our prototype system, we conduct a user study to observe the collaboration styles under this unique setup. We also present the lessons learned by reflecting on the iterative design process of our prototype system.

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aflak: Pluggable visual programming environment with quick feedback loop tuned for multi-spectral astrophysical observations

Malik Olivier Boussejra, Kazuya Matsubayashi, Yuriko Takeshima, Shunya Takekawa, Rikuo Uchiki, Makoto Uemura, Issei Fujishiro

Astronomical Data Analysis Software and System XXVIII ASP Conference Series 523 245 - 248 2019

Research paper (international conference proceedings), Joint Work, Last author, Corresponding author

FIST: A fast, implicit model of the human hand with semi-anatomical structures

NAKADA Masato, BALLET Hélène, FujishiroFUJISHIRO Issei

Proceedings of SIGGRAPH Asia 2018 Technical Briefs (ACM) 34:1 - 34:4 2018.12

Research paper (international conference proceedings), Joint Work, Accepted

There are many opportunities to draw human hands in computer graphics. The motion of internal organs within a human hand has a non-negligible effect on the natural change in the appearance of the hand’s surface. In this work, we propose a method for expressing this change interactively with the use of an implicit model of a human hand that has semi-natomical structures. The model is referred to as Fast, Implicit model with Semi-anatomical sTructures or FIST. In the FIST model, bones are modeled anatomically based on computed tomography imaging, while soft tissues are modeled artificially. It can be controlled only by specifying the angles of the joints. The proposed method can contribute to a compelling expression of the dynamism in such hand motions as grasping, pinching, and scratching in immersive virtual reality and games.

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Arriving light control for color vision deficiency compensation using optical see-through head-mounted display

TANG Ying, ZHU Zhenyang, TOYOURA Masahiro, GO Kentaro, KASHIWAGI Kenji, FUJISHIRO Issei, MAO Xiaoyang

Proceedings - VRCAI 2018: 16th ACM SIGGRAPH International Conference on Virtual-Reality Continuum and its Applications in Industry (ACM) 16: 1 - 16: 6 2018.12

Research paper (international conference proceedings), Joint Work, Accepted

Color vision deficiency (CVD), also known as color blindness, is commonly caused by genetic disorder. Unfortunately, as of 2018, there is not yet a cure for the condition. Contact lenses and glasses with color filter are possible solutions to CVD by applying uniform changes to user’s field of view (FoV). On the other hand, optical see-through head-mounted display (OST-HMD) can provide a controllable overlay to user’s FoV, which could help for making a better solution. To calibrate colors in FoV of a user with CVD, methods that often used, such as the daltonization process, need light reduce feature, which makes calibrated color darker. However, recent commercially available OST-HMDs don’t have a controllable way to decrease the brightness of incoming light. In this paper, we present an approach for light subtraction of OSTHMD using a transmissive LCD panel. A prototype system for achieving a controllable overlay to user’s FoV with OST-HMD by using scene camera, user-perspective camera, and the transmissive
LCD panel was implemented.

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TimeTubes: Automatic extraction of observable blazar deatures from long-term, multi-dimensional datasets

SAWADA Naoko, NAKAYAMA Masanori, UEMURA Makoto, FUJISHIRO Issei

Proceedings of IEEE VIS 2018 (IEEE Computer Society Press) 67 - 71 2018.10

Research paper (international conference proceedings), Joint Work, Accepted

Blazars are attractive objects for astronomers to observe in order to demystify the relativistic jet. Astronomers need to classify characteristic temporal variation patterns and correlations of multidimensional time-dependent observed blazar datasets. Our visualization scheme, called TimeTubes, allows them to easily explore and analyze such datasets geometrically as a 3D volumetric tube. Even with TimeTubes, however, data analysis over such long-term datasets costs them so much labor and may cause a biased analysis. This paper, therefore, attempts to incorporate into the current prototype of TimeTubes, a new functionality: feature extraction, which supports astronomers’ efficient data analysis by automatically extracting characteristic spatiotemporal subspaces.

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aflak: Pluggable visual programming environment with quick feedback loop tuned for multi-spectral astrophysical observations

Boussejra M., Matsubayashi K., Takeshima Y., Takekawa S., Uchiki R., Uemura M., Fujishiro I.

Proceedings of IEEE VIS 2018 (IEEE Computer Society Press) 72 - 76 2018.10

Research paper (international conference proceedings), Joint Work, Last author, Corresponding author, Accepted

With the improvements of telescopes and proliferation of sky surveys, there is always more astrophysical data to analyze, but not so many astronomers. We present aflak, a visualization environment to analyze astronomical datasets. This paper’s contribution lies in that we leverage visual programming techniques to conduct fine-grained astronomical transformations, filtering and visual analyses on multispectral datasets, with the possibility for astronomers to interactively fine-tune all the interacting parameters. As the visual program is gradually designed, the computed results can be visualized in real time, thus aflak puts the astronomer in the loop, while managing data provenance at the same time.

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A figurative and non-topological approach to mathematical visualization

MIYAZAWA Atsushi, NAKAYAMA Masanori, FUJISHIRO Issei

Proceedings of Cyberworlds 2018 (IEEE CPS) 150 - 155 2018.10

Research paper (international conference proceedings), Joint Work, Accepted

The term figurative refers to any form of mathematical visualization that retains strong references to the geometry found in the real world. This paper explains the figuration process for some basic mathematical functions definable in the n-dimensional complex projective space. In the latter part of this paper, we raise a question that has been neglected thus far: What does the Riemann sphere’s axis stand for? We show that the answer can be obtained only by observing from the inside the sphere by setting the viewpoint of the immersive environment to the origin, which is always undefined in projective geometry. We also draw some basic math functions that are familiar to us on the projective plane and observe the invariant properties that exist among the functions, which were thought to be different from one another.

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Adaptive reconfiguration of large display content geometry and layout based on passengers’ position

NAGAO Ken, Ma Kwan-Liu, FujishiroFUJISHIRO Issei

Proceedings of IEEE RTCSA 2018 Workshop on Smart City Based on Artificial Intelligence (SCAI 2018) (IEEE) S1-4:1 - S1-4:5 2018.08

Research paper (international conference proceedings), Joint Work, Accepted

A viewer is likely to see the large display content with a distorted geometry which differs in accordance with his individual standing position. This problem makes it difficult for the viewer to understand the large display content correctly. In particular, when such a large display is used as digital signage advertisement, this problem has negative influences on its advertising effect. On top of that, in most cases, passengers do not originally have interests in the digital signage content, and thus it is not proper to ask them to move to appropriate positions, though this is suggested in previous studies. We, therefore,
propose a novel method which can deliver the content only with little distortion to each passenger without requiring voluntary moves and times. Specifically, the method automatically detects each passenger’s position and adaptively reconfigures the large display content geometry and layout as if the content were rotated toward the positions. We implemented a large display system with the proposed method and evaluated the effectiveness of our method.

TimeTubes: Visual exploration of observed blazar datasets

FUJISHIRO Issei，SAWADA Naoko, NAKAYAMA Masanori, WU Hsiang-Yun, WATANABE Kazuho, TAKAHASHI Shigeo, UEMURA Makoto

Journal of Physics: Conference Series (IOP Press) 1036 ( 1 ) 012011:1 - 012011:13 2018.06

Research paper (international conference proceedings), Joint Work, Lead author, Corresponding author, Accepted, ISSN 17426588

Blazars are attractive objects for astronomers to observe in order to burrow into the magnetic field in the relativistic jet. This paper presents TimeTubes as a novel visualization scheme that allows astronomers to interactively explore characteristic temporal variation patterns in observed blazar datasets. In the TimeTubes spatialization, the two Stokes parameters and their errors with a common timestamp are transformed into an ellipse. A series of such ellipses are aligned in parallel along the timeline to form a 3D volumetric tube. The resulting tube is then colorized by the observed intensities and colors of the blazar, and finally volume-rendered. A designated user interface is provided with visual exploration functions according to Shneiderman's Visual Information Seeking Mantra. In the latest version, an auxiliary mechanism, called visual data fusion, was incorporated to ameliorate data- and mapping-inherent uncertainties for more efficient and effective visual exploration.

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Duality

Masanori Nakayama, Issei Fujishiro

Asian Digital Modeling Contest 2017 Catalogue (Japan Society for Graphic Science) 8 - 11 2017.08

Research paper (other academic), Joint Work, Last author, Corresponding author, Accepted

In the present work, we attempted at expressing human "two-facedness" by the "two-sidedness" of the 3D structures. In the field of geometry, there exists a two-facedness called “duality,” which represents the relationship between diagrams that switch between faces (cells) and vertices. Delaunay diagram and Voronoi diagram give a typical example. We have developed an algorithm to generate a Poisson-disk distribution in an arbitrary shape to make sculptures with those diagrams. The Delaunay diagram generated by Poissondisk distribution point cloud makes up the uniform tetrahedral mesh (except for the surface). Since those cells are close to a regular tetrahedron, Voronoi vertices located on the circumcenters also have an almost uniform distribution.

Visual simulation of whirlwind using a grid and particles

NAKAJIMA Satoshi, FUJISHIRO Issei

Proceedings of NICOGRAPH International 2012 (The Society for Art and Science) 27 - 34 2012.07

Research paper (international conference proceedings), Joint Work, Accepted

In this paper, we present an interactive approach to visual simulation of whirlwind using a grid and particles. High-resolution simulation can be carried out efficiently by perturbing air flow computed on a rough grid with small-scale turbulence. The grid-based simulation first provides a primary whirlwind flow field through modeling its underlying heat convection. Then, the particle-based simulation computes the transport energy of turbulence based on a two-equation k-ipsilon model, which allows us to capture the turbulence details. The dynamism of whirlwind is conveyed effectively by the interaction with rigid and deformable bodies, such as flag, branch and paper, placed on interactively-controllable trajectories. In addition, a simplified variant of particle-based volume rendering is utilized to delineate changes in the translucency of whirlwind, which reflects the amount of sand particles stirred up from the ground.

Visual simulation of bleeding on skin surfaces taking physisorption and congelation into primary account

UEDA Kazuhide, FUJISHIRO Issei

Proceedings of Computer Graphics International 2012 (Computer Graphics Society) 2012.06

Research paper (international conference proceedings), Joint Work, Last author, Corresponding author, Accepted

The liquid dynamics has a significant impact on video works, and bleeding is no exception. Hemorrhage scenes possess highly-important implications, as seen from the fact that they might make the work rated age limit. Lack of visual reality in those scenes would reduce the overall quality of the work. Against this background, we have built upon a commonly-used Lagrangian method, called SPH (Smoothed Particle Hydrodynamics), to simulate bleeding on skin surfaces more faithfully. Remarkable features of the extension are three-fold: (1) bleeding from a wound modeled along with in-vivo blood flow, which takes account of the wound’s shape, hemorrhage volume, and bleed momentum; (2) physisorption of blood on the skin surfaces formulated by introducing an additional adsorption term, analogous to van der Waals force, to the original Navier-Stokes equations and by allowing for saturation of adsorption media; and (3) congelation of blood represented by varying viscosity according to the time exposed to the air.

Feature-driven volume fairing

TAKAHASHI Shigeo, KOBAYASHI Jun, FUJISHIRO Issei

Tenth International Symposium on Smart Graphics (Lecture Notes in Computer Science) (Springer-Verlag, Berlin/Heidelberg/New York) 5531 233 - 242 2009.05

Research paper (conference, symposium, etc.), Joint Work, Accepted, ISSN 0302-9743

Volume datasets have been a primary representation for scientific visualization with the advent of rendering algorithms such as marching cubes and ray casting. Nonetheless, illuminating the underlying spatial structures still requires careful adjustment of visualization parameters each time when a different dataset is provided. This paper introduces a new framework, called feature-driven volume fairing, which transforms any 3D scalar field into a canonical form to be used as communication media of scientific volume data. The transformation is accomplished by first modulating the topological structure of the volume so that the associated isosurfaces never incur internal voids, and then geometrically elongating the significant feature regions over the range of scalar field values. This framework allows us to elucidate spatial structures in the volume instantly using a predefined set of visualization parameters, and further enables data compression of the volume with a smaller number of quantization levels for efficient data transmission.

Designing 6DOF haptic transfer functions for effective exploration of 3D diffusion tensor fields

OGAWA Yuta, FUJISHIRO Issei, SUZUKI Yasuko, TAKESHIMA Yuriko

Proceedings of World Haptics 2009 (IEEE Robotics and Automation Society) 470 - 475 2009.03

Research paper (conference, symposium, etc.), Joint Work, Corresponding author, Accepted

Rapid dissemination of DT-MRI devices has recently evoked
intensive research to come up with effective methods for
grasping the structural features of acquired 3D diffusion tensor fields. In this paper, we further explore the potential of haptization in conjunction with visualization to represent different levels of information on the DT-MRI datasets. The main contribution of this paper is to propose a sophisticated method for utilizing diffusion-based tractography textures mapped on cross-sections to visualize local structures such as nerve tracts, together with appropriate 6DOF haptic transfer functions to haptize elementary diffusion properties. We illustrate the effectiveness of a prototype system featuring a PHANToM Premium 3.0 with an application to a practical DT-MRI human brain dataset.

Music learning through visualization

HIRAGA Rumi,WATANABE Fumiko,FUJISHIRO Issei

Proceedings of Second International Conference on Web Delivering of Music (WEDELMUSIC2002) (IEEE Computer Society Press) 101 - 108 2002.12

Research paper (international conference proceedings), Joint Work, Accepted

Hardware-accelerated selective LIC volume rendering

SUZUKI Yasuko,FUJISHIRO Issei,Li Chen,NAKAMURA Hiroko

Proceedings of IEEE Visualization 2002 485 - 488 2002.10

Research paper (international conference proceedings), Joint Work, Accepted

Comprehensible volume LIC rendering based on 3D signiﬁcance map

Li Chen,FUJISHIRO Issei,SUZUKI Yasuko

Proceedings of SPIE Conference on Visualization and Data Analysis 2002 142 - 153 2002.01

Research paper (international conference proceedings), Joint Work, Accepted

GADGET/IV: A taxonomic approach to semi-automatic design of information visualization applications using modular visualization environment

FUJISHIRO Issei,FURUHATA Rika,ICHIKAWA Yoshihiko,TAKESHIMA Yuriko

Proceedings of IEEE Symposium on Information Visualization 2000 77 - 83 2000.10

Research paper (international conference proceedings), Joint Work, Accepted

Parallel visualization of gigabyte datasets in GeoFEM

FUJISHIRO Issei,TAKESHIMA Yuriko,Li Chen,NAKAMURA Hiroko,SUZUKI Yasuko

Proceedings of Second APEC Cooperation for Earthquake Simulation (ACES) Workshop M. Matsu’ura 557 - 562 2000.10

Research paper (international conference proceedings), Joint Work, Accepted

Solid ﬁtting: Field interval analysis for eﬀective volume exploration

FUJISHIRO Issei,TAKESHIMA Yuriko

Proceedings of Dagstuhl’97 Scientiﬁc Visualization (IEEE Computer Society Press) 65 - 78 2000

Research paper (international conference proceedings), Joint Work, Accepted

Automating transfer function design for comprehensible volume rendering based on 3D ﬁeld topology analysis

FUJISHIRO Issei,AZUMA Taeko,TAKESHIMA Yuriko

Proceedings of IEEE Visualization ’99 467 - 470 1999.10

Research paper (international conference proceedings), Joint Work, Accepted

GADGET: Goaloriented application design guidance for modular visualization environments

FUJISHIRO Issei,TAKESHIMA Yuriko,ICHIKAWA Yoshihiko,NAKAMURA Kyoko

Proceedings of IEEE Visualization’97 245 - 252 1997.10

Research paper (international conference proceedings), Joint Work, Accepted

Human behavior-oriented adaptive texture mapping: A time-critical approach for image-based virtual showrooms

FUJISHIRO Issei,TANAKA Rika,MARUYAMA Tomoko

Proceedings of IEEE Virtual Reality Annual International Symposium(VRAIS) ’97 4 - 11 1997.03

Research paper (international conference proceedings), Joint Work, Accepted

Interval volume: A solid ﬁtting technique for volumetric data display and analysis

FUJISHIRO Issei,MAEDA Yuji,SATO Hiroshi

Proceedings of IEEE Visualization’95 151 - 158 1995.10

Research paper (international conference proceedings), Joint Work, Accepted

ボリュームシームカービング: Gaussian Splattingで再構成された3Dシーンの濃縮

松本悠弥，藤代一成

NICOGRAPH 2025プロシーディング (芸術科学会) F09-1 - F09-8 2025.12

Research paper (conference, symposium, etc.), Joint Work, Last author, Corresponding author, Accepted

XR技術の発展に伴い，撮影動画からの三次元(3D)シーン再構成に対する需要が高まってきている．Neural Radiance Fieldsの登場を皮切りに，3D再構成に関する研究は急速な発展を遂げ，スマートフォンでも簡単に3D再構成ができる環境となりつつある．その一方で，シーンや特定のオブジェクトに対する編集は難しく，未だ途上段階である．そこで本研究は，Gaussian Splattingにより再構成された3Dシーンの自動的な編集を目指す．特に本論文では，シーンの前景部分を濃縮するボリュームシームカービングの手法を提案する．提案手法では，3D Gaussianシーンをボクセルグリッドに変換し，マルチパス動的計画法によるエネルギ最小化に基づくシーム面抽出を繰り返し適用することで，各ガウシアンの幾何的・外観的特徴および空間的一貫性を反映しながら，不要な前景領域を削除し，シーンを濃縮する．異なるシーンに適用し，シーン全体の主要な外観的特徴を維持した前景濃縮の実現性を示すことで，本手法が再構成3Dシーンの自動編集に向けた実用的アプローチであることを実証する．フルペーパー．松本は学生奨励賞受賞．

アニメに様式化された詳細度制御: 誇張表現に向けた対話的計算モデルの提案

青野誠大，福里　司，藤代一成

NICOGRAPH 2025プロシーディング (芸術科学会) S14-1 - S14-4 2025.12

Research paper (conference, symposium, etc.), Joint Work, Last author, Corresponding author, Accepted

手描きアニメにおいて，描画の詳細度は映像内で緻密に制御されており，奥行き感の誇張や対象の強調といった視覚効果を生み出している．しかし，その設計原理は制作者の経験則や暗黙知に依存しており，関連する研究や議論は十分に行われていない．本論文では，手描きアニメの詳細度設計を計算論的に分析し，アニメに様式化された詳細度をパラメトリックに制御するモデルを提案する．詳細度制御に影響する要素として，視点からの距離による大局的要因，各対象の奥行き構造による局所的要因，対象の重要度の三項目に着目し，これらを統合することで画面上の詳細度分布を決定する．ショートペーパー．

色振動を活用して視聴速度の変更を阻害する動画像

北山大起，顾人舒，藤代一成

Visual Computing 2025予稿集 ( 33 ) 1 - 6 2025.09

Research paper (conference, symposium, etc.), Joint Work, Last author, Corresponding author, Accepted

動画像の視聴速度を変更する機能は広く普及しているが，芸術的動画コンテンツの場合，速度変更はその本質的な要素を損ない，視聴体験に大きく影響する可能性がある．したがって，速度変更をあえて阻害し，本来の速度での視聴を促すことは，動画像の芸術性を保護し，メディア伝達の適正化に寄与すると考えられる．しかし，これを目的とした研究はまだ知られていない．そこで本論文では，人間の時間的色覚特性を活用し，視聴速度の変更を阻害する方法を示す．各フレームを色度だけ変化させた2 枚に分割することで，通常速度時は平均色として元の色が知覚され，速度変更時は色が変化して知覚される．動画プラットフォームではなく動画像自体へ細工を施すことで，発信者が阻害を直接的に設定可能となり，視聴環境の自由度も向上する．評価実験の結果，本手法が視聴速度に応じて見えを変化させることが確認され，その有効性が示された．一方，制御パラメタ値の最適化など，実際の利用に際して改善の必要性も明らかになった．VC学生研究賞を共同受賞．

SWEAT：濡れた布の透過性のビジュアルシミュレーションモデル

中村佑騎，藤代一成

Visual Computing 2025予稿集 ( 6 ) 1 - 6 2025.09

Research paper (conference, symposium, etc.), Joint Work, Last author, Corresponding author, Accepted

実世界では，雨模様の天気や液体が布にかかることによって布が濡れる状況は多く，シャツなどに使われる薄い素材の布は濡れることで透過性が上昇する．CG応用においても布が濡れるシーンは多く，重要視されている．しかし，液体に濡れた布の透過性を考慮した研究は少なく，流体シミュレーションや複合BSDFといった一般的な3DCGソフトウェアで扱われるものを用いて，濡れた布の透過性を表現できるモデルはほとんど存在しない．そこで本論文では，実際の布の厚みや糸密度，含水率などの値を参考に，濡れた布の透過性をビジュアルシミュレーションするための独自のモデルとして， a Stochastic model for WEt Absorbent cloth Translucency (SWEAT) を提案する．SWEATは，流体シミュレーションと複合BSDFに簡単に組み合わせることが可能であり，さまざまな素材の濡れた布をビジュアルシミュレーションすることができる．実写画像との比較から，このモデルの妥当性を確認した．

三次元点群からの回転関節をもつ民具文化財のバーチャル操作再現

進士さくら，藤代一成

NICOGRAPH 2024プロシーディング (芸術科学会) F-6:1 - F-6:8 2024.11

Research paper (conference, symposium, etc.), Joint Work, Last author, Corresponding author, Accepted

近年，文化財の保存活動の一環として文化財の三次元形状データのデジタルアーカイブが進められているが，アーカイブされている対象物は静的な物体がほとんどである．民具などの道具の文化財に関しては，道具を操作する体験を通して仕組みの工夫や人々の暮らしを伝えることが重要である．そこで本論文では，計測された道具の静的な三次元モデルからバーチャル環境での一人称視点操作体験を再現し提示する手法を提案する．データの少ない文化財の三次元点群データから道具の可動部を機械学習することは困難であるため，提案手法ではユーザのペイント操作によるおおまかなパーツ指定と回転軸の指定により可動部を推定する．また，指定された回転軸と動画などから推定される可動域をもとにバーチャル操作を可能にする．一軸関節体，二軸以上の関節体の簡単な実例として，川崎市立日本民家園が所蔵する民具に対して本手法を適用し，バーチャル操作体験の実現可能性を示す（NICOGRAPH 2024 学生奨励賞受賞）．

階層的ボリューム構造の非線形レイ走査による効率的なC^1連続のボリュームシェルマッピング

桑名真結香，藤代一成

Visual Computing 2024予稿集 ( 27 ) 1 - 5 2024.09

Research paper (conference, symposium, etc.), Joint Work, Last author, Corresponding author, Accepted

シェルマッピングは，シェル空間に三次元のテクスチャ空間を一対一にマッピングすることで，サーフェイスの微細な構造を表現する手法のひとつである. 本論文では，半透明なマテリアルや陰関数曲面に対応した自由度の高いシェルマッピングを行うために，テクスチャ空間にボリュームテクスチャを導入する．しかし，従来手法は四面体ごとに線形なマッピングを行っているため，アーティファクトが発生する．そこでC1 連続のマッピングを実現するために，レイをテクスチャ空間に非線形にマッピングする. また, 階層的なボリュームテクスチャを利用し, 効率的にサンプリングを行う方法を提案する．

壁面上泡沫流シミュレーションにおける排水の考慮

田原宏都，藤代一成

Visual Computing 2024予稿集 ( 7 ) 1 - 5 2024.09

Research paper (conference, symposium, etc.), Joint Work, Last author, Corresponding author, Accepted

泡沫は，多数の気泡が密集して塊を形成した状態であり，洗剤やビールの泡，消火泡など日常生活のあらゆる場面で観察される．そのため，泡沫は映画やCMにおいて重要な表現対象の一つとなっている．泡沫のビジュアルシミュレーションでは，液体表面上に浮かぶ泡沫の挙動を再現する手法が種々提案されてきた．一方で，固体表面上では，泡沫内の液体が重力で下部に流れる，排水とよばれる現象が泡沫の挙動に大きな影響を及ぼすが，それを考慮した泡沫のビジュアルシミュレーションの研究は殆ど知られていない．そこで本論文では，壁面上に付着した泡沫において，排水の影響を考慮した泡沫の挙動を再現する二次元ビジュアルシミュレーション手法を提案する.

ラゲールボロノイ分割を用いたマントの波打ちアニメーション

西谷真菜，藤代一成

Visual Computing 2024予稿集 ( 13 ) 1 - 5 2024.09

Research paper (conference, symposium, etc.), Joint Work, Last author, Corresponding author, Accepted

デジタルコンテンツにおいてマントが風にはためく様子は，表面を波打つように変形させることで表現できる．しかし，実際に3DCG を用いてアーティストが望むようにマントのアニメーションを制作することは容易な作業ではない．そこで本論文では，ラゲールボロノイ分割を用いて，マントを表すメッシュ表面の起伏を効果的に制御する手法を提案する．また，制作されたアニメーションに対する評価実験の結果も示す．本手法を用いることで，できる限り少数のパラメタを指定するだけで，マントが風によって違和感なく波打つようなアニメーションが制作できる．

MoNACA: 関節軌道曲線の適応的分割によるセルアニメ風モーション変換

小六優衣，藤代一成

NICOGRAPH 2023プロシーディング (芸術科学会) F-7:1 - F-7:8 2023.12

Research paper (conference, symposium, etc.), Joint Work, Last author, Accepted

3DCGにおけるキャラクタアニメーションでは，セルアニメのような手描きらしい動作を表現するために，コマ打ちを用いることがある．セルアニメにおけるコマ打ちは，少ないポーズ数で動作を表現するために，余剰な動作の省略や速さの強調などの演出を含んでおり，現実動作とは異なる質感をもっている．そのため，モーションキャプチャデータのような現実動作に一様なダウンサンプリング処理を施しても，セルアニメに特有な動作の質感までは再現しづらい．本論文では，モーションキャプチャデータをセルアニメらしい動作へ変換するシステムMoNACA (Motion transfer by Nakawari Adaptation for Cel-anime Articular trajectories)を提案した．MoNACA では，動作の余剰性と距離配分を考慮することで関節軌道から分割点群を選択し，軌道曲線を純化する．そして，動作の速さに応じた中割りポーズ群を選択することで動作を省略し，セルアニメらしい動作を実現する．小六は学生奨励賞受賞．

メッシュシェーダを用いた効率的な粒子ベース流体表面再構成

西舘祐樹，藤代一成

Visual Computing2023予稿集 25:1 - 25:4 2023.09

Research paper (conference, symposium, etc.), Joint Work, Last author, Corresponding author, Accepted

動画からのヴィネットイラスト半自動生成のプロトタイピング

生井麻結，藤代一成

Visual Computing2023予稿集 2:1 - 2:4 2023.09

Research paper (conference, symposium, etc.), Joint Work, Last author, Corresponding author, Accepted

現在，肥大化するメディアデータに対処するため，様々な要約技術が発表されている．しかし，その多くは同種メディア変換であり，圧縮率に限界がある．そこで本研究では，ヴィネットイラストに注目する．ヴィネットイラストは，アニメやゲームの物語を簡潔に表現し，一目でその世界観を理解させることができる．本論文では，ユーザの嗜好を反映しつつ，動画からヴィネットイラストを半自動生成するシステムVigNet を提案する．

熱気流を考慮した火の粉の三次元ビジュアルシミュレーション

吉田千夏，藤代一成

Visual Computing2023予稿集 7:1 - 7:4 2023.09

Research paper (conference, symposium, etc.), Joint Work, Last author, Corresponding author, Accepted

燃焼現象は映画やゲームにおいて重要な表現対象のひとつであり，火炎や煤，煙，火の粉など複数の要素からなる．
燃焼を表現するためには火炎以外も欠かせない重要な要素であるが，アーティストによる後付けのエフェクトによってそれらしく見せているものが多い．本論文では，燃焼の迫真性を高めるうえで特に重要な火の粉に着目し，焚火のような木材の燃焼を対象とした，火の粉の物理ベースビジュアルシミュレーション手法を提案する．提案手法では，粒子法と格子法を組み合わせて燃焼をシミュレーションし，熱気流による抗力や重力を考慮した運動方程式に基づいて，火の粉のダイナミクスを計算する．

離散モース理論に基づくアート作品のリーディングラインの位相解析

柴崎史典，藤代一成

Visual Computing2023予稿集 4:1 - 4:5 2023.09

Research paper (conference, symposium, etc.), Joint Work, Last author, Corresponding author, Accepted

画家や写真家の作品制作では，リーディングラインを構図内に含ませることで，作品の主役を強調しながら周囲にも視線を誘導することが意識されている．静止画の誘目測度として，一般的に顕著度が用いられているが，このようなスカラ特徴量では視線の流れが表現されない．そこで本論文では，顕著性マップに対する離散モース理論に基づいた位相解析によって，リーディングラインを視覚分析する手法を提案する．さらに様々なアート作品に対する実際の観察者の視線追跡結果と比較し，本手法の妥当性と限界を調査する．

組上げ型振付制作プロセスに基づくハウスダンスデザインシステムのプロトタイピング

大字諒，藤代一成

NICOGRAPH 2022会議録 (芸術科学会) F-3:1 - F-3:8 2022.11

Research paper (conference, symposium, etc.), Joint Work, Last author, Accepted

昨今，多数の3DCG制作ソフトウェアの登場により，制作プロセスやそれを支援するユーザインタフェースが洗練され，3Dモーション制作に対する障壁は大きく軽減されてきた．しかし，モーション制作の基本がキーフレーム操作であることに変わりはなく，依然として，複雑なダンスモーションはおろか自然なモーションの制作にもかなりの技術が要求される．一方で，実際のダンスモーション制作プロセスはより単純である．特に，過去から現在までのダンス文化の集合体であるハウスダンスでは，ダンサーは各部位のモーションを要素として捉え，それらを連動させる組上げ型の制作プロセスを経ることで，様々な振付を制作してきた．そこで本研究では，様々なモーションと実際の振付制作で行う操作の関係性を明らかにし，多種多様なダンスモーションの直観的制作を可能にするビジュアルプログラミング環境を提案する．プロトタイプシステムでは，要素モーションとそのモーションに対する操作を表すノードをインタラクティブに接続することで，実際の振付制作プロセスを再現している．実際に制作されたダンスモーションの視聴者評価から，提案環境の妥当性が実証された．大字は学生奨励賞受賞．

三次元ボロノイ分割を用いたオパールのビジュアルシミュレーション—遊色効果の再現—

橫田壮真，杉田俊平，藤代一成

Visual Computing 2022予稿集 17:1 - 17:6 2022.10

Research paper (conference, symposium, etc.), Joint Work, Last author, Accepted

宝石として用いられるオパールの多くは遊色効果とよばれる光学特性をもち，虹色の模様を発現する．ダイヤモンド，ルビー，サファイヤなどの宝石の大半は単結晶または多結晶であるのに対して，オパールは非晶に分類され，複雑な内部構造をもつ．そのためオパールの内部構造の再現には，計算資源の制約のもとで，遊色効果を再現するために必要十分な空間スケールでのモデリングが必要である．本研究は，オパールの内部構造を三次元ボロノイ分割を用いてモデリングすることで，結晶学に基づいた遊色効果の模様を再現する．ボロノイ図の特性に着目することで，既存の研究と比較して空間計算量を大幅に削減する．さらに，オパールを構成する粒子の粒径や，粒子内に含まれる不純物による光の散乱および吸収係数，回折格子の傾きといった4 種類のパラメタの調整によって，オパールの汎用的なモデリングが可能であることを示す．

DVF：ハンドジェスチャインタフェースを用いた仮想シーン知覚像のスケール再現に向けて

星川潤，藤代一成

Visual Computing 2022予稿集 29:1 - 29:7 2022.10

Research paper (conference, symposium, etc.), Joint Work, Last author, Accepted

旅行先などで，印象的な情景を写真に収めた際，自身が肉眼で捉えた風景と，写真に記録された風景との間に大きな差異を覚えることがある．この現象は，人間の視知覚とカメラの投影モデルの特性の違いが原因のひとつであると考えられる．人間は風景のなかで興味ある対象を部分的に強調しながら捉えるのに対し，一般的なカメラは風景全体を平等に捉える．よって，写真を介して主観的な印象や感動を他者に効果的に伝えることは易しいことではない．このような課題は現実シーンだけでなく，仮想シーンでも同様に存在する．多様な体験が可能なメタバースにおいて，効果的にユーザの感動を共有することはひじょうに重要な課題である．本論文では，仮想シーンにおけるユーザの注目部分を拡大処理した画像を自動出力するシステムDVF（Digitus ViewFinder）を提案する．注目部分の指定にハンドジェスチャを用いることで，ユーザは没入感を損なわずに，自身が捉えた情景に近いシーン画像を得ることができる．評価実験の結果，我々は仮想シーンにおける拡大率に関する新たな知見を得，それらの特性を反映させた拡大率関数の推定と応用機能の実現に関する見込みが得られた．

最適視点からのポーズ抽出を伴うセルアニメ風モーション変換—速さ分布とポーズ面積に注目した動作評価

小六優衣，藤代一成

Visual Computing 2022予稿集 27:1 - 27:7 2022.10

Research paper (conference, symposium, etc.), Joint Work, Last author, Accepted

3DCG におけるキャラクタアニメーションでは，セルアニメのような手描きらしい動作表現を実現するために，コマ打ちを用いることがある．セルアニメにおけるコマ打ちは，少ないポーズ数で動作を表現するために，余剰な動作の省略や速さの強調といった演出を含んでいるため，現実動作とは異なる質感をもっている．そのため，モーションキャプチャデータのような現実動作に一様なダウンサンプリング処理を施しても，セルアニメに特有な動作の質感までは再現されづらい．そこで本論文では，セルアニメの制作技法に基づき，モーションキャプチャデータをセルアニメらしい動作へ変換する手法を提案する．提案手法では，モーションデータの特性を，速さ分布とポーズ面積を用いて評価する．そして両者から動作認識に適したカメラ視点を選択し，その視点においてセルアニメらしい動作を実現するのに最も効果的なポーズを同時に抽出する．

レイ走査高速化のためのアフィン変換レイアライメント

西舘祐樹，藤代一成

Visual Computing 2022予稿集 20:1 - 20:7 2022.10

Research paper (conference, symposium, etc.), Joint Work, Last author, Accepted

近年，レイトレーシングがリアルタイムレンダリングにおいても使われ始めている．しかし，依然としてレイトレーシングの時間計算量は大きく，リアルタイムに出射できるレイの本数は限られている．本論文では，レイトレーシングの時間計算量を削減する新たな手法として，アフィン変換レイアライメントを提案する．本手法はアフィン変換を用いて複数本のレイを1 本にまとめながら，シーンから得られる交点を維持することにより，計算結果に誤差を発生させずにレイ走査を高速化する．さらに，本手法をプライマリレイ走査やステレオレンダリング，マルチフレームレンダリングに適用する具体的応用も提案し，単純な実装で時間計算量を削減できることを示す．

経年劣化に伴う金属物体上の塗膜の亀裂・湾曲表現—静力学的破壊判定と位置ベース変形による準静的過程のビジュアルシミュレーション—

石飛晶啓，中山雅紀，藤代一成

Visual Computing 2022予稿集 2:1 - 2:6 2022.10

Research paper (conference, symposium, etc.), Joint Work, Last author, Accepted

風雨などの作用による経年劣化を表現する技法であるウェザリングは，写実的なCGの描画に欠かせないものであり，数多くの手法が提案されている．特に日常生活に偏在する金属は代表的な研究対象であるが，現実的なシーンを想定するならば金属に塗布された防腐剤の経年劣化も表現すべきである．そこで本研究では，金属物体上の塗膜を対象としたウェザリングを提案する．提案手法では塗膜をポリゴンメッシュで表現し，塗膜内部における力の釣合いに基づいて破壊判定を行う静力学シミュレーションと，幾何学的な制約に従って頂点を移動させる位置ベースの湾曲シミュレーションを組み合わせることで塗膜を変形させる．本手法により，マテリアルの操作だけでは表現が難しい立体的な変形を伴う塗膜の経年劣化が再現できる．

深層学習を用いた書道作品における書体変換—篆書の文字認識と行書の作品生成—

二ノ宮梢平，藤代一成

NICOGRAPH2021予稿集 (芸術科学会) F-8:1 - F8-8 2021.11

Research paper (conference, symposium, etc.), Joint Work, Last author, Corresponding author, Accepted

書道は日本の伝統的な文化である一方で，書道展は経験者の間で完結している．その要因の一つとして，鑑賞が書道の習熟度合いに大きく依存していることが挙げられる．そこで，本研究では書道初心者を対象にした鑑賞支援として，文字認識と他の書体への変換を提供するシステムを開発する．文字認識には，畳込みニューラルネットワークを用いた手法を提案する．漢字が偏旁冠脚といったパーツから構成されるという特徴を利用して，書道作品に用いられる難読文字の認識を実現する．これにより，少ないデータ数と少ないクラス分類で，より性能の高い文字認識が可能になる．一方，他の書体への変換には，敵対的生成ネットワークを用いた手法を提案する．文字骨格に対する筆跡の付与を学習したモデルを用いて，任意の漢字による書道作品画像を生成する．ここで，筆順情報と筆画情報をもった骨格画像を用いることで，効果的な筆跡の学習を実現する．そして，この二種類の手法を実装したシステムにより，書道作品に用いられる漢字の特定から書道作品画像の生成まで，直観的な操作に基づく鑑賞体験を可能にする．二ノ宮は学生奨励賞受賞．

種数0 のサーフェスにおけるヤコビアンフリーな変形シミュレーション

吉良俊亮，中山雅紀，藤代一成

NICOGRAPH2021予稿集 (芸術科学会) F-2:1 - F2-8 2021.11

Research paper (conference, symposium, etc.), Joint Work, Accepted

CG におけるオブジェクトの変形は，物質の多様な性質を表現するうえで，欠かすことのできない要素である．近年の映像作品の高精細化から，変形のシミュレーションにもまた，より高精細なものが求められている．一般的な変形シミュレーション手法として，メッシュを用いた手法が挙げられるが，計算時間が多くかかることから，リアルタイム性を重視する場合，衝撃が加わった際にオブジェクト表面が波打つ様子などの細やかな変形表現は描画されない．一方，リアルタイム性を重視した変形シミュレーション手法として，変位マッピングを用いたアプローチが知られているが，この手法は二次元平面上に適用することを想定しているため，テクスチャ空間と実空間との間に非線形な関係が存在するオブジェクト表面に適用すると，ヤコビ行列を用いた座標変換による歪みを変形に生じさせてしまう．そこで，本論文では，射影によりテクスチャに格納した実空間座標を用いてシミュレーションを計算することにより，オブジェクト表面にテクスチャ空間と実空間との間の歪みを解消した，変位マッピングによるヤコビアンフリーな変形シミュレーションを，種数0の任意オブジェクトに対して実現する手法を提案する．吉良は学生奨励賞受賞．

SpiCa：ろくろ型三次元透明キャンバスによるエフェクト作成支援

池田理和乃，藤代一成

Visual Computing 2021予稿集 21:1 - 21:6 2021.09

Research paper (conference, symposium, etc.), Joint Work, Last author, Corresponding author, Accepted

光や炎，煙，水，風といった不定形の現象を具象化した効果はエフェクトと総称され，幅広い分野の作品制作において欠かせない表現である．本論文では，ろくろ型三次元透明キャンバスを用いることで，立体的なエフェクトを描画できるシステムとしてSpiCa（Spinning Canvas）を提案する．キャラクタを中心としたイラストでは，構図を整理するため，エフェクトの流れの軌跡を簡単な形状の曲面上に想定することが多いことに注目し，SpiCaでは，こうした面を，対象を囲う回転可能なろくろ型のキャンバスとしてデザインすることで，三次元的なエフェクトのスケッチを容易にする．池田はCGVI賞受賞．

Personalized image recoloring for color vision deficiency compensation

朱臻陽，豊浦正広，郷健太郎，柏木賢治，藤代一成，黄田津，茅暁陽

Visual Computing 2021予稿集 9:1 - 9:2 2021.09

Research paper (conference, symposium, etc.), Joint Work, Accepted

二色塗分けスパークラインを用いた一次元時系列COVID-19感染データの可視化

本田健悟，斎藤隆文，藤代一成

Visual Computing 2021予稿集 31:1 - 31:5 2021.09

Research paper (conference, symposium, etc.), Joint Work, Last author, Corresponding author, Accepted

COVID-19 のパンデミックに関して，私たちは各種メディアが生成する可視化により，日々の感染状況を把握している．今回のパンデミックは多くのデータの多角的な考察が必要であるが，既存の可視化だけでは十分な分析環境を提供できているとはいえない．本論文では，二色塗分け法を用いたスパークラインを提案する．提案手法は，全国や地域別のCOVID-19 の感染データに適用することで，詳細と概要を関連する文章の近接で読み取ることができる．これにより，ビジュアルコミュニケーションを活発化し，より多くの情報をもとに今回のパンデミックについて考察できる視覚分析環境の提供を目指す．

大域照明を考慮した人物全身のディジタル画像コンポジット

大河原将,藤代一成

Visual Computing 2020予稿集 4:1 - 4:6 2020.12

Joint Work, Last author, Accepted

本論文では，大域照明を考慮したコンポジットパイプラインを新たに提案する．このパイプラインでは，大域照明効果のうち，背景要素から前景要素へのカラーブリーディングとソフトシャドウを再現することができる．これにより，照明の整合性を保持したコンポジットが可能となっている．コンポジットの対象には，幅広い応用を期待して，人物を選択した．なお，このパイプラインでは，人物のフルショットに対応しているため，影の影響が無視できない場面への適用が可能となっている．

色覚障がい支援のための個人適応型色変換アルゴリズム

朱臻陽,豊浦正広,郷健太郎,藤代一成,柏木賢治,茅暁陽

Visual Computing 2018 口頭発表・招待講演・ポスター発表予稿集 5:1 - 5:6 2019.06

Joint Work, Accepted

自然さ保存とコントラスト強調を考慮した色覚補償ための色変換アルゴリズム

朱臻陽，豊浦正広，郷健太郎，藤代一成，柏木賢治，茅暁陽

Visual Computing 2018口頭発表・招待講演・ポスター発表予稿集 (画像電子学会) 34:1 - 34:6 2018.06

Research paper (conference, symposium, etc.), Joint Work, Accepted

線変形操作を用いた変視症検査方法

市毛大道，豊浦正広，郷健太郎，柏木賢治，藤代一成，茅暁陽

Visual Computing 2018口頭発表・招待講演・ポスター発表予稿集 (画像電子学会) 8:1 - 8:4 2018.06

Research paper (conference, symposium, etc.), Joint Work, Accepted

雪の踏み散らしシミュレーション　- 焼結作用の考慮 -

TAKAHASHI Tetsuya, FUJISHIRO Issei

Visual Computing/グラフィクスとCAD合同シンポジウム2012 (画像電子学会／情報処理学会／映像情報メディア学会) 2012.06

Research paper (conference, symposium, etc.), Joint Work, Last author, Corresponding author, Accepted

我々は, 雪に関する従来のCG 表現における不自然さの一つである“雪の付着が起こらない”という点に着目した. 雪の付着の主要因は焼結作用にあるため, その作用を含め, より物理的に忠実な雪表現をするための研究を行ってきた.本論文では, 雪表現のための主要素である“雪としての振舞い”, “焼結作用による動的剛体への雪の付着”および“対流の影響を含めた熱伝導”を実現するための手法を提案する. “雪としての振舞い”は一般的なナビエ· ストークス方程式の粘性項を改良することにより実現した. “焼結作用による動的剛体に対する雪の付着”に関しては, 付着力が焼結作用によって変化することを考慮し, ナビエ· ストークス方程式に焼結項を追加することで表現した. “対流の影響を含めた熱伝導”は, 熱伝導方程式をSPH 法で離散化するとともに, 外気が表面粒子に与える影響を考慮することで再現した.

Accurate visualization of galaxy velocity ﬁelds from three-dimensional integral ﬁeld spectroscopy data

Rikuo Uchiki，Malik Olivier Boussejra, Liyu Zhu, Yuriko Takeshima, Kazuya Matsubayashi， Makoto Uemura，Issei Fujishiro

EuroVis 2020 Posters (Eurographics Association) 2020.04

Research paper (international conference proceedings), Joint Work, Last author, Corresponding author, Accepted

A deformation method for simulating coating degradation while taking mechanical behavior into account

Akinori Ishitobi, Masanari Nakayama, Issei Fujishiro

Proceedings of Cyberworlds 2019 2019.10

Joint Work, Last author, Corresponding author, Accepted

Access to Document (DOI)

Realizing pseudo color bleeding with a deep composite image

Masaru Ohkawara, Issei Fujishiro

Proceedings of Cyberworlds 2019 2019.10

Joint Work, Accepted

Access to Document (DOI)

Automatic generation of artworks using virtual photoelastic material

MIYAZAKI Kazuki, FUJISHIRO Issei

Poster Proceedings of ACM SIGGRAPH 2018 (ACM) 1:1 - 1:2 2018.08

Research paper (international conference proceedings), Joint Work, Accepted

Photoelasticity is known as one of the phenomena related to polarization and is defined as the change in birefringence of transparent material when internal force is applied. Interference fringes appear by irradiating the material with polarized light when viewing it through the polarizer. In this study, we attempt to apply the concept of photoelasticity to generative art. Assuming there is virtual stress distribution in the two-dimensional material, our method automatically generates artworks with photoelasticity. A GPU-based acceleration of the current implementation is also discussed.

Access to Document (DOI)

下地との相互作用を考慮した多層ラッカー塗装マテリアルの光学的検討

亀井聖斗，藤代一成

情報処理学会第88回全国大会講演論文集 (情報処理学会 ) ( 2 ) 235 - 236 2026.03

Research paper (conference, symposium, etc.), Joint Work, Last author, Corresponding author

家具や楽器をはじめとする木材製品は，製品の価値を高めるために下地を活かした塗装を施す場合がある．このような塗装は，光が透過する程度にラッカー塗料やサーフェイサを薄く何度も塗り重ねるため，多層構造をなす．多層構造をもつマテリアルモデルは，汎用BSDFを用いれば反射特性を高精度に近似できるが，塗装マテリアルの再現に限定する場合はパラメタ定義が冗長である．この結果，パラメタ値の調整がユーザの負担になることが欠点として挙げられる．そこで本研究では，極力少ないパラメタ，かつ塗装条件のシミュレーションを行いやすい形式で塗装マテリアルを提案する．特に，透けて下地が見えるような多層構造をもつ塗装を本研究の対象とし，ケーススタディの一つとして木材の塗装について検討する．

明暗境界線の統一的スタイル化手法

八木寛季，藤代一成

情報処理学会第88回全国大会講演論文集 (情報処理学会 ) ( 2 ) 237 - 238 2026.03

Research paper (conference, symposium, etc.), Joint Work, Last author, Corresponding author

絵画において，物体表面の明部から暗部へと遷移する境界領域－明暗境界線は，形状の立体感や質感を表現するのに重要となる．例えば，人間の肌の明暗境界線に赤みを加えることで，肌の表面下散乱を表現することがある．このように，絵画において明暗境界線への着色が一般的な表現であるにもかかわらず，コンピュータグラフィックスにおいてはその描画手法が十分に議論されてきたとはいえない．そこで本研究では，明暗境界線の描画プロセスを「検出」「形状制御」「合成」の3 段階でモデル化し，陰と影を同一のパラメタ空間で制御可能にするシェーディングモデルを提案する．これにより，光学現象の違いに関わらず，適用範囲や形状の制御が容易な明暗境界線描画手法の実現を目指す．本手法は主に非写実的表現を対象とするが，写実的表現における表面下散乱の近似にも応用可能である．

GPU work graph 実装に向けた粒子ベース流体シミュレーションにおける表面メッシュの適応的生成

宮下慧悟，杉田俊平，藤代一成

映像情報メディア学会技術報告 (映像情報メディア学会) 50 ( 7 ) 130 - 133 2026.03

Research paper (conference, symposium, etc.), Joint Work, Last author, Corresponding author, ISSN 1342-6893

流体シミュレーションは，CG において写実的な流体現象を表現するために広く利用されている．特に粒子ベースシミュレーションは，微細な流体現象を正確に再現できる点で注目されている．このシミュレーションデータをレンダリングするには，粒子の集合から表面メッシュを生成する必要がある．一般的な手法では，シミュレーション領域をグリッドで分割し，3次元密度場を導出して等値面を抽出する．しかし，グリッド解像度の向上に伴い計算コストが増大する課題がある．GPU による並列化や適応的な解像度制御方式が提案されているが，高解像度グリッドの保持が依然として課題である．これに対して，本研究では，GPU work graphを活用した表面メッシュ生成手法を検討する．GPU work graphは，命令をノード，依存関係をエッジとするグラフ構造を用いて効率的なスケジューリングを可能にする新機能であり，レジスタを介したデータ共有による空間計算量の削減が期待される．本稿では，局所性の高い法線計算やクラック補完のパターン分類を提案し，従来のGPU 駆動命令を用いて提案手法を実装，検証することで，GPU work graphを活用した最適化の可能性を探る基礎的知見を得た．

布の挙動における周期性軽減のためのモーション補間ベースのアニメーショングラフ生成

西田真菜，藤代一成

情報処理学会研究報告 (情報処理学会) 2025-CG-200 ( 41 ) 1 - 6 2025.11

Research paper (conference, symposium, etc.), Joint Work, Last author, Corresponding author, ISSN 2188-8949

風になびいている布は，CG コンテンツ内で3D メッシュを用いて表現されることが多い．このとき，布の動きは，計算コストやデータ量を削減するために，ループ可能な短いメッシュアニメーションを繰り返し再生して表現されることがある．しかしループアニメーションは，パターンの周期性が知覚されやすく，アニメーションの品質を劣化させる要因になると考えられる．そこで本研究では，布の二状態の補間アニメーションを作成する処理を用いて，短いアニメーションとその間の遷移から構成されるアニメーショングラフを生成する手法を提案する．ユーザ操作に基づいてアニメーショングラフが生成でき，このグラフをたどることで，少ないデータ量で周期性を避けた複雑なアニメーションを合成できる．

大気エアロゾルの粒径分布を考慮した遠景の再現

大貫誉，横田壮真，小林拓，藤代一成

情報処理学会研究報告 (情報処理学会) 2025-CG-199 ( 9 ) 1 - 6 2025.09

Research paper (conference, symposium, etc.), Joint Work, Last author, Corresponding author, ISSN 2188-8949

大気汚染は世界中で大きな問題となっている．黄砂やPM2.5 などの大気エアロゾルは，人間の健康に影響を及ぼすだけでなく，視程や大気の色合いにも影響を及ぼす．大気エアロゾルを考慮したシーンのレンダリングは多々提案されているが，汚染物質の種類によって変化する視程や大気の色合いを考慮したレンダリングについては十分な研究がなされていない．本稿で提案する手法は，Polarization Optical Particle Counter（偏光光散乱式粒子計測器）による大気エアロゾルの測定データを利用して消散係数を計算し，多重散乱を考慮した大域照明を評価したうえでスペクトラルレンダリングを実行することで，実際の汚染物質の粒径分布にしたがって視程や色合いの変化を伴う遠景の再現を試みる．大貫はCGVI優秀研究発表賞を受賞．

民具文化財のバーチャル操作体験に向けて---川崎市立日本民家園所蔵民具の三次元再構成とXR体験化---

進士さくら，関　悦子，藤代一成

デジタル技術による文化財情報の記録と利活用７ (独立行政法人国立文化財機構奈良文化財研究所) 2025.03

Research paper (bulletin of university, research institution), Joint Work, Last author, Corresponding author

民具などの道具の文化財の学習では，道具を操作する体験を通して仕組みの工夫や人々の暮らしを伝えることが重要であるが，動的な三次元データのデジタルアーカイブは困難である．そこで本稿では，計測された道具の静的な三次元モデルからバーチャル環境での一人称視点操作体験を再現し提示する手法を提案する．関節をもつ道具の簡単な実例として，川崎市立日本民家園が所蔵する民具に対して本手法を適用し，バーチャル操作体験の実現可能性を示す．また，本システムを用いて，民具の操作体験を通じて文化財の特徴や構造を理解できるようなアプリケーションを開発し，小学校の授業において実際に使用した事例とそのアンケート結果を示す．

色振動を用いて視聴速度の変更を阻害する動画像の提案

北山大起，顧　人舒，藤代一成

情報処理学会第87回全国大会講演論文集 (情報処理学会 ) ( 1 ) 535 - 536 2025.03

Research paper (conference, symposium, etc.), Joint Work, Last author, Corresponding author

セルルックアニメ制作のための詳細度制御モデルの提案

青野誠大，藤代一成

情報処理学会第87回全国大会講演論文集 (情報処理学会 ) ( 2 ) 503 - 504 2025.03

Research paper (conference, symposium, etc.), Joint Work, Last author, Corresponding author

濡れによる布の透過性のビジュアルシミュレーション

中村佑騎，藤代一成

情報処理学会第87回全国大会講演論文集 (情報処理学会 ) ( 2 ) 477 - 478 2025.03

Research paper (conference, symposium, etc.), Joint Work, Last author, Corresponding author

大気エアゾル粒径分布を考慮した視程変化の再現

大貫　誉，小林　拓，横田壮真，藤代一成

情報処理学会第87回全国大会講演論文集 (情報処理学会 ) ( 2 ) 473 - 474 2025.03

Research paper (conference, symposium, etc.), Joint Work, Last author, Corresponding author

GPU work graphを用いた流体シミュレーションの適応的解像度制御

宮下慧悟，杉田俊平，藤代一成

情報処理学会第87回全国大会講演論文集 (情報処理学会 ) ( 2 ) 483 - 484 2025.03

Research paper (conference, symposium, etc.), Joint Work, Last author, Corresponding author

CGでは流体を写実的に表現するためにシミュレーションを利用する. その効率化のために，並列計算に対するGPUの利用が進むほか，描画結果の品質低下を抑えながらも計算コストを削減する解像度制御が行われている. 一方, 近年GPU駆動の計算パラダイムが注目され, その一つであるGPU work graphは, GPUで実行する命令群をあらかじめ有向グラフとして定義することで, CPUの介入なく, GPUへの命令発行や効率的な分岐実行を実現する. 本研究では，このGPU work graphを利用し, CPU-GPU間の通信を極力削減した流体シミュレーションおよびその適応的な時間解像度制御を試みる.

色振動を用いて視聴速度の変更を阻害する動画像の提案と評価

北山大起，顧　人舒，藤代一成

映像情報メディア学会技術報告 (映像情報メディア学会) 49 ( 10 ) 401 - 404 2025.03

Research paper (conference, symposium, etc.), Joint Work, Last author, Corresponding author, ISSN 1342-6893

オンライン動画配信サービスの流行に合わせて，時間効率を求める人々による高速視聴が増加している．しかし，芸術的動画コンテンツの場合，視聴速度の変更は鑑賞の姿勢として適切ではない可能性がある．視聴速度の変更をあえて阻害することは，メディア伝達の適正化に寄与すると考えられるが，これを目的とした研究はまだ知られていない．そこで本研究では，色振動を活用して視聴速度の変更を視覚的に阻害する手法を提案し，その評価を行う．動画像の各フレームを知覚的等価な2 枚に分割することで，視聴速度に応じて見えを変化させることが可能であることがわかった．評価実験の結果，本手法が有効に機能する可能性が示されると同時に，実際の利用に際して改善の必要性も明らかになった．

セルルックアニメ制作に向けた詳細度制御モデルの提案

青野誠大，藤代一成

映像情報メディア学会技術報告 (映像情報メディア学会) 49 ( 10 ) 377 - 380 2025.03

Research paper (conference, symposium, etc.), Joint Work, Last author, Corresponding author, ISSN 1342-6893

手描きアニメでは，詳細度の変化が映像表現として重視され，よく利用される．演出意図に応じて対象の詳細度を適切にデザインすることで，奥行きを効果的に演出したり，特定の対象を強調したりできる．この技法を3DCG によるアニメ表現にも適用することで魅力的な映像表現が可能となるが，アニメに様式化された詳細度の制御に関する研究や議論はまだ十分にされてきていない．そこで本研究では，対象をキャラクタに限定し，アニメ的な詳細度の制御を行うモデルの構築を目指す．デザインに関わる要素を考慮した仮想的な距離，さらに距離と詳細度の関係性をふまえた関数を導入することにより，アニメで用いられる誇張表現を試みる．さらに，評価実験を通してその有効性と課題を考察する．

SWEAT：透過性を考慮した濡れた布のビジュアルシミュレーションモデル

中村佑騎，藤代一成

映像情報メディア学会技術報告 (映像情報メディア学会) 49 ( 10 ) 53 - 56 2025.03

Research paper (conference, symposium, etc.), Joint Work, Last author, Corresponding author, ISSN 1342-6893

近年，CG において，雨模様の天気や液体がかかることによって衣類が濡れるシーンが増加しており，濡れた布の表現は重要視されている．濡れていない布の透過性や，布と液体の相互作用だけを扱う研究は多く知られているが，液体に濡れた布の透過性を考慮した研究はほとんど知られていない．そこで本研究では，実際の布の厚みや糸密度，含水率などの値をもとに，濡れた布の透過性をビジュアルシミュレーションするための独自のモデルa Stochastic model for WEt Absorbent cloth Translucency (SWEAT) を提案する．SWEAT を用いることでさまざまな素材の濡れた布をビジュアルシミュレーションすることができ，実写画像との比較から，このモデルの妥当性も確認した．

GPU work graphを用いたSPHによる流体シミュレーションの時間解像度制御

宮下慧悟, 杉田俊平, 藤代一成

情報処理学会研究報告 (情報処理学会) 2025-CG ( 197 ) 1:1 - 1:6 2025.03

Research paper (conference, symposium, etc.), Joint Work, Last author

GPU駆動の新たな機能としてGPU work graphが提案されている．この機能では，単一の命令にとどまらず，命令群の実行順序や命令間のデータの授受といった依存関係を含めてシェーダに記述する．GPUはこの関係を参照でき，命令の切替えや分岐処理の効率化が期待されている．さらに，起動するスレッド数についても柔軟に制御できる．本稿では，GPU work graphを流体シミュレーションの数値計算とその高速化手法である時間解像度制御に適用し，有用性を検討する．数値計算における依存関係や解像度制御に必要な命令の分岐を，GPU work graphを用いて表現し，効率的なGPU スケジューリングを可能にする．さらに，異なるノードタイプやベンダのGPUで実行し，その効果について検証する．

ColorizeDiffusion: Improving Reference-Based Sketch Colorization with Latent Diffusion Model

Yan D., Yuan L., Wu E., Nishioka Y., Fujishiro I., Saito S.

Proceedings 2025 IEEE Winter Conference on Applications of Computer Vision Wacv 2025 5092 - 5102 2025

Diffusion models have achieved great success in dual-conditioned image generation. However, they still face significant challenges in image-guided sketch colorization, where reference and sketch images usually exhibit different semantics and spatial structures. This mismatch, termed 'distribution shift' in this peper, results in various artifacts and degrades the colorization quality. To address this issue, we conducted thorough investigations into the image-prompted latent diffusion model and developed a two-stage training framework to mitigate the effects of distribution shift based on our analysis. Comprehensive quantitative comparisons, qualitative evaluations, and user studies were performed to demonstrate the superiority of our proposed methods. Additionally, ablation studies were conducted to assess the impact of the distribution shift and the selection of reference embeddings. Codes are made publicly available at https://github.com/tellurion-kanata/colorizeDiffusion.

Access to Document (DOI)

Gaussian Splattingで再構成された3Dシーンにおける前景物体の半自動切抜き

松本悠弥, 藤代一成

情報処理学会研究報告 (情報処理学会) 2024-CG ( 196 ) 19:1 - 19:6 2024.11

Research paper (conference, symposium, etc.), Joint Work, Last author

XR 技術の発展に伴い，撮影動画からの三次元(3D)シーン再構成に対する需要が高まってきている．Neural Radiance Fieldsの登場を皮切りに，3D再構成に関する研究は急速な発展を遂げ, スマートフォンでも簡単に3D再構成ができる環境となりつつある．その一方で，シーンや特定のオブジェクトに対する編集は難しく，未だ途上段階である．本研究では，Gaussian Splattingにより再構成された3Dシーンの半自動的な編集を目指し，ユーザの簡単な入力から前景物体を自動で推定しシーンから切り抜く手法を提案する．

Visualizing, Exploring and Analyzing Big Data: A 6-Year Story

Bikakis N., Papastefanatos G., Chrysanthis P.K., Papemmanuil O., Auber D., Frey S., Fujishiro I., Hauptmann H., Liu S., Ma K.L., Schreck T., Sedlmair M., Sharaf M.A.

SIGMOD Record 53 ( 2 ) 54 - 57 2024.07

ISSN 01635808

Information Visualization has been one of the cornerstones of Data Science, turning the abundance of Big Data being produced through modern systems into actionable knowledge. Indeed, the Big Data era has realized the availability of voluminous datasets that are dynamic, multidimensional, noisy and heterogeneous in nature. Transforming a data-curious user into someone who can access and analyze that data is even more burdensome now for a great number of users with little or no support and expertise on the data processing part.

Access to Document (DOI)

オパールのビジュアルシミュレーション—焼結の再現と回折方向の効率的な探索—

橫田壮真, 藤代一成

情報処理学会研究報告 (情報処理学会) 2024-CG ( 193 ) 11:1 - 11:6 2024.03

Research paper (conference, symposium, etc.), Joint Work, Last author

宝石として用いられるオパールは，遊色効果とよばれる光学現象を発現する．その特徴的な光学特性から，オパールは自然科学，産業，人文科学の分野において価値が高い材料である．一方で，オパールはコロイド多結晶とよばれる複雑な内部構造をもつため，オパールをCGで写実的に再現する手法は未だ確立していない．本研究では，3次元加法的重み付きボロノイ図と，その母点が形成するネットワークのパーコレーションを用いることでオパールの生成過程を近似する．また，X線回折理論で用いられるEwaldの作図を応用して，オパール内部における可視光の回折方向を効率よく探索する手法を提案する．最終的に，スペクトラルレンダリングによって視覚的に尤もらしい結果を得る.

非線形レイを利用したボリュームシェルマッピング

桑名真結香, 藤代一成

情報処理学会研究報告 (情報処理学会) 2024-CG ( 193 ) 10:1 - 10:6 2024.03

Research paper (conference, symposium, etc.), Joint Work, Last author

シェルマッピングは，既存の三角形ポリゴンを法線方向に押し出して得られるプリズムに，三次元のテクスチャ空間を一対一にマッピングすることで，サーフェイスの複雑な微細構造を表現する．本研究では，半透明なマテリアルや陰関数曲面に対応した自由度の高いシェルマッピングを行うため，テクスチャ空間にボリュームデータを導入する．これをボリュームシェルマッピングとよぶことにする．加えて，四面体分割によるアーティファクトのないボリュームシェルマッピングを手法を提案する．さらに，高速化を行うとともに，評価実験によって提案手法の有用性を実証する．

熱狂感を増幅するリアクティブな観客NPCの生成

石貫雄大，藤代一成

情報処理学会第86回全国大会講演論文集 (情報処理学会 ) ( 4 ) 529 - 530 2024.03

Research paper (conference, symposium, etc.), Joint Work, Last author, Corresponding author

バーチャル空間で体験される音楽ライブコンテンツは年々増加しているが, それらは現実の体験に比べ一体感が不足し, 熱狂感が低下する. 現実のライブ体験の分析によれば, 周囲の観客の反応が一体感を生み, それに同調することで熱狂が伝搬, 増幅される. そこで本研究では熱狂をサポートするため観客の代替となるNPC (Non-Player-Character) を生成する. NPCとはプレイヤー操作に依存しない自律的なキャラクタである. パフォーマンスに対しリアクティブな挙動を行い, 情動モデルとユーザのインタラクションに基づいて周囲と同調的な動作する NPCにより, 実際の観客と同様の熱狂感をサポートする.

壁面上泡沫流における排水効果の再現

田原宏都，藤代一成

情報処理学会第86回全国大会講演論文集 (情報処理学会 ) ( 2 ) 231 - 232 2024.03

Research paper (conference, symposium, etc.), Joint Work, Last author, Corresponding author

泡沫は液体の表面現象における重要な状態である. 食品や洗剤, 消火など日常生活のあらゆる場面に応用されており, その挙動を表現することは液体のビジュアルシミュレーションの課題のひとつとなっている. 泡沫の液体表面上運動のビジュアルシミュレーション手法は多々提案されているが, 固体表面上でその挙動に大きな影響を及ぼす排水効果やそれに伴うピンチオフなどの特有の現象については既存研究では十分考慮されていない. そこで本研究では, 壁面上に付着した泡沫の流れのビジュアルシミュレーション手法を提案する. 排水の影響を考慮することで, ピンチオフを含んだ壁面上の泡沫の挙動を実現する.

再構成された3Dシーンにおける物体の半自動切抜き

松本悠弥，藤代一成

情報処理学会第86回全国大会講演論文集 (情報処理学会 ) ( 2 ) 201 - 202 2024.03

Research paper (conference, symposium, etc.), Joint Work, Last author, Corresponding author

XR技術の発展に伴い, カメラ動画からの3次元 (3D) シーン再構成に対する需要が高まってきている. Neural Radiance Fieldsの登場を皮切りに, カメラ動画をもとにした3D再構成に関する研究は急速な発展を遂げ, スマートフォンで簡単に3次元再構成ができる環境となりつつある. その一方で, シーンや特定のオブジェクトに対する編集は難しく, 未だ途上段階である.本研究では3D Gaussian Splattingにより再構成されたシーンに対して半自動的な編集を施すことで, 異なるシーン内の物体の単一シーンへの集約や単一シーンの縮約を目指す. ユーザの簡単な入力から対象のオブジェクトを自動で推定し, シーンから切り抜く手法を提案する.

マントの風変形アニメーションの制作支援システム

西谷真菜，藤代一成

情報処理学会第86回全国大会講演論文集 (情報処理学会 ) ( 2 ) 205 - 206 2024.03

Research paper (conference, symposium, etc.), Joint Work, Last author, Corresponding author

アニメーション作品において，キャラクタの纏うマントのはためくアニメーションは重要なシーンを構築する要素となることがある．しかしマントの変形アニメーションを制作することは手間のかかる作業であり，例えば，マントの形状をボーンで制御する場合には，キーフレームごとに各ボーンの適切な回転量を定義する必要がある．本研究では，マントが風によって翻るような形状変化に着目し，そのようなアニメーションの制作を効率化することを目的とする．ユーザの入力に基づき，マントに対して大まかな形状変化と表面の波打つような形状変化の2種類を施すことで，風の影響を受けているように見えるマントの変形アニメーションの制作を容易にする．

非線形レイトレーシングを用いたボリュームシェルマッピング

桑名真結香，藤代一成

情報処理学会第86回全国大会講演論文集 (情報処理学会 ) ( 2 ) 169 - 170 2024.03

Research paper (conference, symposium, etc.), Joint Work, Last author, Corresponding author

サーフェイスの微細な構造を表現する方法は多岐に渡る. その一つであるシェルマッピングでは, シェル空間にテクスチャ空間で定義した構造を割り当てる. 本研究では, テクスチャ空間をOpenVDBのボリュームデータを用いて表現することで, 半透明なマテリアルの表現を可能にする. また従来の手法ではシェル空間を四面体分割し, 重心座標系をマッピングに用いることが一般的であったが, 本研究では四面体分割を用いることで生じるアーティファクトや計算の手間を避けるため非線形なレイを扱う. ワールド空間ではレイトレーシング, テクスチャ空間では非線形なボリュームレイキャスティングを行うことで, 効率良くレンダリングする方法を提案する.

マントの波打ち変形アニメーションの制作支援

西谷真菜，藤代一成

映像情報メディア学会技術報告 (映像情報メディア学会) 48 ( 8 ) 139 - 143 2024.03

Research paper (conference, symposium, etc.), Joint Work, Last author, Corresponding author, ISSN 1342-6893

様々なデジタルコンテンツにおいて，キャラクタの纏う衣服のアニメーションには高い需要が存在する．衣服のなかでも，マントが風によってはためくアニメーションは，その躍動感の高さからシーンのなかで重要な要素となることが多い．しかし，3DCGを用いてアーティストが望んだマントのアニメーションを制作することは容易な作業ではない．そこで本研究では，少数のパラメタからマントが風によって波打つようなアニメーションを制作するシステムを提案する．同システムは，ラゲールボロノイ分割を用いて，マントのメッシュ表面の起伏を効果的に制御する．

Gaussian Splatting再構成された3Dシーンにおける物体の半自動切抜き

松本悠弥，藤代一成

映像情報メディア学会技術報告 (映像情報メディア学会) 48 ( 8 ) 19 - 22 2024.03

Research paper (conference, symposium, etc.), Joint Work, Last author, Corresponding author, ISSN 1342-6893

XR技術の発展に伴い，撮影動画からの三次元(3D) シーン再構成に対する需要が高まってきている．Neural Radiance Fields の登場を皮切りに, 三次元再構成に関する研究は急速な発展を遂げ，スマートフォンでも簡単に三次元再構成ができる環境となりつつある．その一方で，シーンや特定のオブジェクトに対する編集は難しく，未だ途上段階である．本研究では，Gaussian Splattingにより再構成された3D シーンの半自動的な編集を目指し，ユーザの簡単な入力から前景物体を自動で推定しシーンから切り抜く手法を提案する．既存の学習済シーンと自身で撮影した動画からGaussian Splatting により再構成された3D シーンに対して本手法を実行し，視覚的に尤もらしい前景部分の切抜きが可能であることを確認した.

バーチャルライブにおける同調的な観客NPCの合成による熱狂感の実現

石貫雄大，藤代一成

映像情報メディア学会技術報告 (映像情報メディア学会) 48 ( 8 ) 127 - 130 2024.03

Research paper (conference, symposium, etc.), Joint Work, Last author, Corresponding author, ISSN 1342-6893

近年注目されているバーチャルライブは，実際のライブと比べて熱狂感が感じづらい．そこで本研究では，現実の観客を代替するNon Player Character (NPC)の合成に取り組み，熱狂感のあるバーチャルライブの実現を目指す．社会心理学分野の熱狂感に関する知見に基づき，心理的要素とプレイヤーを含む周囲の観客との心理的相互作用を考慮することで，同調的に応援動作する観客NPCを合成する．

可搬性を考慮したリモート/ローカル混成型のコンピュータグラフィックス実習教材

大河原将, 藤代一成

IPSJ SIG Technical Report (情報処理学会) 2023-CG ( 192 ) 46:1 - 46:4 2023.11

Research paper (conference, symposium, etc.), Joint Work, Last author

今日，遠隔授業と対面授業を併用するハイフレックス型授業が浸透している．ハイフレックス型授業は，多様な受講スタイルを許容する柔軟性をもつ一方で，一部の分野に関しては運用上の課題を抱える可能性がある．たとえば，コンピュータグラフィックス・可視化・クロスリアリティをはじめとするビジュアルコンピューティング分野は，特殊なソフトウェアやハードウェアを用いる場合があり，遠隔授業における教育の品質維持が課題として知られている．本稿では，ハイフレックス型授業に適合するコンピュータグラフィックス実習教材を提案する．提案教材は，Google Colaboratory を含むリモートマシンとローカルマシンの双方で動作し，多様な実習スタイルを提供することができる．

動画からのヴィネットイラスト半自動生成：ビューアの嗜好の反映

生井麻結，藤代一成

映像情報メディア学会技術報告 (映像情報メディア学会) 47 ( 9 ) 301 - 304 2023.03

Research paper (conference, symposium, etc.), Joint Work, Last author, Corresponding author, ISSN 1342-6893

現在，肥大化するメディアデータに対処するため，様々な要約技術が発表されている．しかし，その多くは同種メディア変換であり圧縮率に限界がある．そこで本研究では，ヴィネットイラストに注目する．ヴィネットイラストは，ビデオ映像作品やゲームの物語コンテンツを凝縮して表現し，一瞥でその世界観を理解させられる．動画からヴィネットイラストへの変換ができれば，より情報の圧縮率の高い要約が期待できる．そこで本稿では，視線追跡を利用してビューアの嗜好を反映したヴィネットイラストを，動画から半自動生成する手法を提案する．

スケッチ入力を用いた手描きAnime調の髪アニメーション制作支援システム〜制御パラメータの調整〜

児玉大輔，藤代一成

映像情報メディア学会技術報告 (映像情報メディア学会) 47 ( 9 ) 57 - 60 2023.03

Research paper (conference, symposium, etc.), Joint Work, Last author, Corresponding author, ISSN 1342-6893

日本の手描きアニメ（以下，手描きAnimeと表す）における髪のアニメーションは，躍動感の表現や印象的なシーンの制作において重要な役割を果たす．しかし，3DCGでこのような揺れを制作する場合，設定すべきパラメタが多く，すべて手作業で理想のモーションを得るのは困難である．そこで本研究では，手描きAnime調の髪の揺れを制作するための支援システムを提案する．スケッチ入力により揺れ方を例示し，制御パラメタで調整することで，表現力を維持しながら作業の効率化を可能とする．

微分位相幾何学に基づくリーディングラインの視覚分析と視線追跡結果の比較

柴崎史典，藤代一成

映像情報メディア学会技術報告 (映像情報メディア学会) 47 ( 9 ) 89 - 92 2023.03

Research paper (conference, symposium, etc.), Joint Work, Last author, Corresponding author, ISSN 1342-6893

画家や写真家の作品制作では，明確な線だけでなく，似た形状の並びや筆遣い等を利用したリーディングラインを構図内に含ませることで，作品の主役を強調しながら周囲にも視線を誘導することが意識されている．静止画の誘目測度として，一般的に顕著度が用いられているが，このようなスカラ特徴量では視線の流れが表現されない．そこで本稿では，顕著性マップから抽出したMorse-Smale複体の部分グラフに基づく，リーディングラインの視覚分析手法を提案する．さらに実際の観察者の視線追跡結果と比較し，その妥当性を実証する.

動画の例示と回転軸の指定による点群からの関節体のモーション再構成

進士さくら，藤代一成

映像情報メディア学会技術報告 (映像情報メディア学会) 47 ( 9 ) 135 - 138 2023.03

Research paper (conference, symposium, etc.), Joint Work, Last author, Corresponding author, ISSN 1342-6893

三次元バーチャル空間の利用例として，現実のシーンの擬似体験・追体験がある．特に文化財など，現実世界での操作が困難な物体に対し，触知可能な3Dモデルによる疑似体験を実現する価値がある．しかし，現在の三次元再構成技術で得られるモデルは静的であり，道具の操作などの動的な相互作用を伴う体験を実現できない．そこで本研究では，可動部をもつ物体として関節体に注目し，ある姿勢の静的な点群から，物体の運動を撮影した動画とユーザによって入力された回転軸をもとに三次元の動的なシーンを再現する．メッシュモデルから作成した点群と実際の民具の文化財を撮影した点群に対して本手法を実行し，視覚的に尤もらしい関節運動が再現できた．

熱気流を考慮した火の粉の動きのビジュアルシミュレーション

吉田千夏，藤代一成

情報処理学会第85回全国大会講演論文集 (情報処理学会 ) ( 2 ) 941 - 942 2023.03

Research paper (conference, symposium, etc.), Joint Work, Last author, Corresponding author

燃焼現象は映画やゲームにおいて重要な表現対象のひとつであり，火炎に加えて，煤や煙，火の粉などの要素からなる．火炎のビジュアルシミュレーション手法は多々提案されているが，火炎以外の要素については，アーティストによる後付けのエフェクトによってそれらしく見せているものも多くあり，映像に迫真性が欠けてしまう場合がある．そこで本研究では，特に火の粉に着目し，焚火のような木材の燃焼を対象とした物理的ビジュアルシミュレーション手法を提案する．火炎を伴う燃焼源から火の粉を発生させ，熱気流の抗力と浮力を考慮した運動方程式に基づいて火の粉のダイナミクスを計算する．

スケッチ入力を用いた手描きAnime調の髪アニメーション制作支援システム

児玉大輔，藤代一成

情報処理学会第85回全国大会講演論文集 (情報処理学会 ) ( 2 ) 929 - 930 2023.03

Research paper (conference, symposium, etc.), Joint Work, Last author, Corresponding author

手描きAnime 調の髪の揺れを制作するための支援システムでは，個々の髪の揺れをスケッチ入力によって定めた後に，パラメタを調整して髪全体の揺れを設定している．個々の髪の揺れに関しては，まずスケッチ入力により髪の揺れのキーフレームアニメーションを作成し，これに対し補間を行うことで揺れを決定する．このとき，キーフレーム間に挿入する補間フレームの個数と「ためつめ」の度合いをパラメタによって指定することで補間結果を調整できる．こうして得られた揺れの形状に対して制御パラメタを考慮しながらボーンへ反映させ，衝突回避を行った後にメッシュをボーンにより変形させることで，髪全体のアニメーションを生成する．このとき，ボーンを視線に垂直な平面内で変形させることで二次元的な揺れを実現する．

動画からのヴィネットイラスト半自動生成

生井麻結，藤代一成

情報処理学会第85回全国大会講演論文集 (情報処理学会 ) ( 2 ) 933 - 934 2023.03

Research paper (conference, symposium, etc.), Joint Work, Last author, Corresponding author

微分位相幾何学に基づく静止画における視線誘導方策の視覚分析

柴崎史典，藤代一成

情報処理学会第85回全国大会講演論文集 (情報処理学会 ) ( 2 ) 939 - 940 2023.03

Research paper (conference, symposium, etc.), Joint Work, Last author, Corresponding author

著名な画家や写真家の作品制作では，明確な線だけでなく，似た形状の並びや，グラデーション，筆遣いなどといったリーディングラインを構図内に示すことで作品の主役を強調しながら，その周囲にも視線を誘導し，観る者に作品の隅々まで観察させることが意識されている．静止画に対する誘目測度として一般的に顕著度が用いられているが，このようなスカラ特徴量では視線の流れが表現されない．そこで本発表では，顕著性マップから抽出したReeb graphに基づく，リーディングラインの可視化手法を提案する．さらに，絵画作品から得られた視線経路を実際の観察者に対する視線追跡結果と比較し，本手法の妥当性を証明する.

回転軸の指定による点群からの関節体のモーション再構成

進士さくら，藤代一成

情報処理学会第85回全国大会講演論文集 (情報処理学会 ) ( 2 ) 891 - 892 2023.03

Research paper (conference, symposium, etc.), Joint Work, Last author, Corresponding author

バーチャル空間でのCGコンテンツの利用例して，現実のシーンの擬似体験・追体験がある．特に文化財のような貴重な物体や危険な物体など，現実での操作が困難な物体に対し，触知可能な3Dモデルによる疑似体験を実現する価値がある．可動部分をもつ物体の単純な例として，蓋付きの箱や手回し扇風機など，関節周りの回転運動をする物体に注目する．再構成した点群を動かすためには，対象の動作を理解し，得られた点群を後から効果的に変形する技術が必要である．本発表では，回転軸の指定と回転運動の動画による例示をもとに，対象物の関節周りの回転運動を再構成する方法を提案する．

直交マルチディスプレイを用いた裸眼立体映像におけるフレームブレイク効果の検証

徳永恵太，藤代一成

情報処理学会研究報告 (情報処理学会) 2022-CG-187 ( 5 ) 1 - 4 2022.09

Research paper (conference, symposium, etc.), Last author

徳永らは，アナモルフォーシスとよばれるデザイン技法を応用した裸眼立体視システムを開発してきた．このシステムでは，オブジェクトの位置とユーザの視点位置によってはオブジェクトの一部が描画範囲外となり欠落し，立体感を低下させていることが問題となっている．本稿では，この問題を緩和するために，近年映画制作などに使われているframe-break とよばれる手法をこのシステムに適用し，立体感の増強に与える効果を検証する．

遠隔社会におけるグラフィックスパラダイム

大河原将，藤代一成

FIT2022講演論文集 (情報処理学会) ( 3 ) 71 - 74 2022.09

Research paper (conference, symposium, etc.), Joint Work, Last author

多光源大域照明レンダリングにおける経路誘導の効率化とそのGPU高速化

杉田俊平，藤代一成

2022年度第50回画像電子学会年次大会予稿集 (画像電子学会) S10-2:1 - S10-2:4 2022.09

Research paper (conference, symposium, etc.), Joint Work, Last author

大域照明レンダリングは, 高い写実性から映画・建築・デザイン分野を中心に利用されている. 主要手法の一つであるモンテカルロ・レイトレーシングにおいて, 出力画像は最終的な収束値から異なる画素を含んでおり, 収束までに多数のサンプル点が必要となる課題がある. ゆえに, サンプル当たりの分散低減効果を改善し, 少ないサンプル数で低分散を実現する最適化手法が必要とされている. 経路誘導は, 事前推定により求まる放射輝度分布に沿って重点的サンプリングを適用し, 効率的な経路構築を行うことで分散低減を実現する. しかし多光源シーンでは, 各光源からの寄与に伴う分布形状の複雑さから推定が進まず, 精度の低い学習分布による経路構築によりかえって分散が増大する可能性がある. 本稿では, 各光源からの寄与を考慮した光源選択を行い, 放射輝度分布の分布推定を改善することで, 多光源照明計算を効率化する手法を提案する. また提案手法をGPUプログラムとして実装し, 通常のパストレーシングと比較して最大で41.4 %の分散低減効果を示した.

遊色効果再現のための三次元ボロノイ分割を用いたオパールのモデリング

横田壮真，杉田俊平，藤代一成

2022年度第50回画像電子学会年次大会予稿集 (画像電子学会) S10-3:1 - S10-3:4 2022.09

Research paper (conference, symposium, etc.), Joint Work, Last author

宝石として用いられるオパールの多くは遊色効果とよばれる光学特性をもち，虹色の模様を発現する．ダイヤモンド，ルビー，サファイヤなどの宝石の大半は単結晶または多結晶であるのに対して，オパールは非晶質に分類され，複雑な内部構造をもつ．そのためオパールの内部構造の再現には，計算資源の制約のもとで，遊色効果を再現するために必要十分な空間スケールでのモデリングが必要である．本研究では，オパールの内部構造を三次元ボロノイ分割を用いてモデリングすることで，結晶学に基づいた遊色効果の模様を再現する．さらに，オパールを構成する粒子の粒径や，粒子内に含まれる不純物による光の散乱係数および吸収係数，回折格子の傾きといった4種類のパラメタを用いて，オパールの汎用的なモデリングが可能であることを示す．

時系列データのスマート可視化

本田健悟，小林拓，斎藤隆文，藤代一成

第50回可視化情報シンポジウム講演論文集 (可視化情報学会) OS9-4:1 - OS9-4:5 2022.08

Research paper (conference, symposium, etc.), Joint Work, Corresponding author

私たちが日々送受信するSNSやニュースなどの情報のやり取りの多くは，スマートフォンやタブレット端末などのモバイルデバイスを介して行われるそうした情報のなかには，気象や公衆衛生，人口動向など日常生活に密着する時系列データに関するものが多く含まれている．本発表では，大気粒子の飛散に関する時系列データをモバイルデバイスを用いた単語サイズの可視化に適用する例を通して，その効果や今後の実用性を検討する．

三次元面分光データの微分位相解析による銀河構造の可視化

打木陸雄，竹島由里子，松林和也，植村誠，藤代一成

第50回可視化情報シンポジウム講演論文集 (可視化情報学会) GS2–3:1 - GS2–3:6 2022.08

Research paper (conference, symposium, etc.), Joint Work, Corresponding author

Figurative and non-transcendental approach to mathematical visualization

MIYAZAWA Atsushi, NAKAYAMA Masanori, FUJISHIRO Issei

Wolfram Technology Conference 2018 (Wolfram) 2018.10

Research paper (conference, symposium, etc.), Joint Work, Accepted

It is believed that the answers to various problems of basic math consisting of elementary calculus and geometry faced by high-school and college students have already been well-established, and there might not be any room for further study or discussion. But actually, pitfalls are found almost everywhere in this area, especially when it comes to graphing functions to understand their behavior in a higher dimensional space that we can neither experience nor access directly. Although topological abstraction plays an exceptionally important role in modern mathematics, it can greatly reduce the amount of information to what is needed for the problem to be just identified and lead to a lot of misconceptions. Rather than such abstraction processes, we advocate that figurative approaches are often considered as prime solution candidates. The work presented at Cyberworlds had been completely rewritten in Wolfram language. At the conclusion, it was also shown that the fifth* representation of the real projective plane could be visualized.
*The fourth one had already described in the appendix of Anschauliche Geometrie (by Hilbert and Cohn-Vossen, first published in 1952).

全景映像の適応的半透明ブレンディングによる視野狭窄の緩和と視野特性の評価

登野拓志，茅　暁陽，豊浦正広，郷健太郎，柏木賢治，藤代一成

映像情報メディア学会技術報告 (映像情報メディア学会) 42 ( 26 ) 61 - 64 2018.08

Research paper (conference, symposium, etc.), Joint Work, Last author, ISSN 1342-6893

現在，世界には視覚障がいをもつ患者が2億8,500万人ほどおり，そのなかに視野障がいをもつ患者が，緑内障に限定しても，6,000万人程度含まれるといわれている．視野障がいの一つに視野狭窄という症状があり，その症状をもつ患者のための視覚支援手法の研究はこれまでに多く行われてきたが，その多くが視覚情報以外の情報の提示により支援するものであり，視覚情報の提示を工夫して直接支援する研究は少ない．本稿では，視野狭窄をもつ患者に対して，計算処理を施した外界シーンを呈示することによる視覚支援手法を提案し，その有効性の評価結果を報告する．また，この実験に付随する問題である，視野特性についても併せて報告する．

色覚障がい支援のための個人適応型色変換アルゴリズム

朱　臻陽，豊浦正広，郷健太郎，藤代一成，柏木賢治，茅　暁陽

映像情報メディア学会技術報告 (映像情報メディア学会) 42 ( 26 ) 25 - 28 2018.08

Research paper (conference, symposium, etc.), Joint Work, ISSN 1342-6893

Foreword to the Special Issue on PacificVAST 2018

FUJISHIRO Issei, SEO Jinwook

Visual Informatics (Elsevier) 2 ( 1 ) 1 - 1 2018.03

Research paper (scientific journal), Joint Work

Access to Document (DOI)

Optical polarization variations in the blazar PKS1749+096

UEMURA Makoto, ITOH Ryosuke, LIODAKIS Ioannis, BLINOV Dmitry, NAKAYAMA Masanori, SAWADA Naoko, WU Hsiang-Yun, FUJISHIRO Issei

Publications of the Astronomical Society of Japan (Oxford Academic) 69 ( 6 ) 96:1 - 96:12 2017.12

Research paper (scientific journal), Joint Work, Accepted

We report on the variation in the optical polarization of the blazar PKS 1749+096 observed in 2008–2015. The degree of polarization (PD) tends to increase in short flares having a time-scale of a few days. The object favors a polarization angle (PA) of 40◦–50◦ at the flare maxima,
which is close to the position angle of the jet (20◦–40◦). Three clear polarization rotations were detected in the negative PA direction associated with flares. In addition, a rapid and large decrease in the PA was observed in the other two flares, while another two flares showed no large PA variation. The light curve maxima of the flares possibly tend to lag behind the PD maxima and color-index minima. The PA became -50◦ to -20◦ in the decay phase of active
states, which is almost perpendicular to the jet position angle. We propose a scenario to explain these observational features, where transverse shocks propagate along curved trajectories. The favored PA at the flare maxima suggests that the observed variations were governed by the variations in the Doppler factor, $delta$. Based on this scenario, the minimum viewing angle of the source, min = 4:8◦–6:6◦, and the location of the source, Δr> 0.1 pc, from the central black hole were estimated. In addition, the acceleration of electrons by the shock and synchrotron
cooling would have a time-scale similar to that of the change in $delta$. The combined effect of the
variation in $delta$ and acceleration/cooling of electrons is probably responsible for the observed diversity of the polarization variations in the flares.

Access to Document (DOI)

What does the Riemann sphere's axis stand for?: Understanding the big picture of how mathematical functions behave

MIYAZAWA Atsushi, NAKAYAMA Masanori, FUJISHIRO Issei

Proceedings of ACM SIGGRAPH Asia 2017 Symposium on Education (ACM) 5-1 - 5-3 2017.11

Research paper (international conference proceedings), Joint Work, Accepted

Access to Document (DOI)

Swellart: Sketch-based deformed design using constrained swelling

YUASA Kaiki, NAKAYAMA Masanori, FUJISHIRO Issei

The Journal of the Society for Art and Science (The Society for Art and Science) 16 ( 4 ) 102 - 109 2017.11

Research paper (scientific journal), Single Work, Accepted

In this study, we propose a system, called Swellart, which allows even novices to intuitively generate deformed 2D graphic designs. For developing the system, we put a particular focus on swelling as a general method of deformation. By premising a simple process to swell a target image until it fits to the shape of a given frame, every user can easily imagine the whole deformation process and its resultant visual effects. On the target image, a user hollows out a range to be deformed, and then the range is mesh-divided. For each of the divided cells, the user imposes various design constraints and performs swelling. Accordingly, the system can generate a variety of deformed designs. In this paper, we provide the basic design procedures and typical results, and discuss remaining issues to be addressed.

A Method for generating piled fabrics with fluff-Level details of geometry

IKEDA Yasunari, TOGO Yutaro, FUJISHIRO Issei

NICOGRAPH2017 (The Society for Art and Science) 17 - 24 2017.11

Research paper (conference, symposium, etc.), Joint Work, Accepted

Immersive math environment continuable to cross-sectional complex projective 2-space

MIYAZAWA Atsushi, NAKAYAMA Masanori,FUJISHIRO Issei

Full Paper Proceedings of the Eleventh Asian Forum on Graphic Science F40-1 - F40-6 2017.08

Research paper (international conference proceedings), Joint Work, Accepted

As is well-known, in quantum mechanics the complex wave plays an essential role, which can explain the natural phenomena very well. In other words, it can be said that the rules of nature are written with logic using complex numbers. We are accustomed to the convenience of
visualizing the overall behavior of a function by means of its graph. In the case of a complex function, however, this approach has not seemed workable for a long time because to depict a pair of complex numbers (an input z and the output of a function f) we would need four dimensions. Especially in mathematical visualization, we have demonstrated thus far that how the fourth dimension is conceptualized seems to be successfully justified by using a cross section and a projection of an object appropriately, described in terms of polar coordinates (instead of Cartesian coordinates). At
the end of this paper, we raise the question that has been neglected thus far: “What does the Riemann sphere’s axis stand for?” We show that the answer can be obtained only by observing from the inside the sphere by setting the viewpoint of the immersive environment on the point (0, 0), which is always undefined in projective geometry.

Time-Tubes: Visual fusion and validation for ameliorating uncertainties of blazar datasets from different observatories

SAWADA Naoko, NAKAYAMA Masanori, YUN Hsiang-Yun, UEMURA Makoto, FUJISHIRO Issei

CGI'17 Proceedings of the Computer Graphics International Conference (ACM ICPS) 14-1 - 14-6 2017.06

Research paper (international conference proceedings), Joint Work, Accepted

Astronomers have been observing blazars to solve the mystery of the relativistic jet. A technique called TimeTubes uses a 3D volumetric tube to visualize the time-dependent multivariate observed datasets and allows astronomers to interactively analyze the dynamic behavior of and relationship among those variables. However, the observed datasets themselves exhibit uncertainty due to their errors and missing periods, whereas periods interpolated by TimeTubes result in a dierent type of uncertainty. In this paper,
we present a technique for ameliorating such data- and mappinginherent
uncertainties: visual fusion of datasets for the same blazar from two different observatories. Visual data fusion with Time-Tubes enables astronomers to validate the datasets in a meticulous manner. This is a short paper presented at CGI2017, held at Keio University Hiyoshi Campus, Yokohama, Japan, June 27-30 (presentation day: June 28), 2017.

Access to Document (DOI)

音源に同期する運指に注目した吹奏アニメーションの自動生成

堀井絵里, 藤代一成

Visual Computing/グラフィクスとCAＤ合同シンポジウム2017 (画像電子学会・情報処理学会・映像情報メディア学会) 41:1 - 41:4 2017.06

Research paper (conference, symposium, etc.), Joint Work

本研究では，管楽器を演奏するキャラクタの吹奏アニメーションを，音楽に容易に同期させるため，音源から自動的に運指のアニメーションを生成することを目指す．より具体的には，ウインドシンセサイザを用いて作成したMIDI 音源を解析することにより，吹奏の情報を得る．得られた情報をキャラクタの指や腕，および管楽器のピストンやスライドに適用することにより，運指が音源に同期した，自然な吹奏アニメーションを実現する．ポスタNo.41として発表．

異方性をもつ紙繊維シートの破断シミュレーション

篠崎紗衣子, 中山雅紀, 藤代一成

Visual Computing/グラフィクスとCAＤ合同シンポジウム2017 (画像電子学会・情報処理学会・映像情報メディア学会) 33:1 - 33:4 2017.06

Research paper (conference, symposium, etc.), Joint Work

本発表では，2 次元平面上に縦横の方向性をもたせた繊維を配置し，繊維同士をつなげて繊維のシート（紙繊維シート）を生成する．さらにシートにはシートを充填する填料，繊維の回転に反発するヒンジばねのモデルを組み込み，シートに力が加えられたときこれらに発生する力学的な作用を考慮して破断のシミュレーションを行う．ポスタNo.33として発表．

器官の準解剖学的データを用いた手のモデリング

中田聖人, 藤代一成

Visual Computing/グラフィクスとCAＤ合同シンポジウム2017 (画像電子学会・情報処理学会・映像情報メディア学会) 28:1 - 28:4 2017.06

Research paper (conference, symposium, etc.), Joint Work

本発表では，骨格の解剖学的なデータと，腱，筋肉，皮膚，血管の人工的なデータを用いて，各器官の形状をスカラ関数として表現し，組み合わせる．このようにしてモデリングされた手の準解剖学的なモデルを動かし，スカラ関数を変化させることで，内部構造の動きによる手の表面の変化を陰的にモデリングできる手法を提案する．ポスタNo.28として発表．

Visual analysis approach for the process of sound processing by composers in Spectral School

TAKAKURA Yuriko, NAKAYAMA Masanori, KOJIMA Yuriko, FUJISHIRO Issei

IPSJ SIG Report (Information Processing Society of Japan) 2017-MUS-115 ( 36 ) 1 - 6 2017.06

Research paper (conference, symposium, etc.), Joint Work

Making many-to-many parallel coordinate plots scalable by asymmetric biclustering

YUN Hsiang-Yun, NIIBE Yusuke, WATANABE Kazuho, TAKAHASHI Shigeo, UEMURA Makoto, FUJISHIRO Issei

Proceedings of IEEE PacificVis 2017 (IEEE Computer Society) 305 - 309 2017.04

Research paper (international conference proceedings), Joint Work, Accepted

Datasets obtained through recently advanced measurement techniques tend to possess a large number of dimensions. This leads to explosively increasing computation costs for analyzing such datasets, thus making formulation and verification of scientific hypotheses very difficult. Therefore, an efficient approach to identifying feature subspaces of target datasets, that is, the subspaces of dimension variables or subsets of the data samples, is required to describe the essence hidden in the original dataset. This paper proposes a visual data mining framework for supporting semiautomatic data analysis that builds upon asymmetric biclustering to explore highly correlated feature subspaces. For this purpose, a variant of parallel coordinate plots, many-to-many parallel coordinate plots, is extended to visually assist appropriate selections of feature subspaces as well as to avoid intrinsic visual clutter. In this framework, biclustering is applied to dimension variables and data samples of the dataset simultaneously and asymmetrically. A set of variable axes are projected to a single composite axis while data samples between two consecutive variable axes are bundled using polygonal strips. This makes the visualization method scalable and enables it to play a key role in the framework. The effectiveness of the proposed framework has been empirically proven, and it is remarkably useful for many-to-many parallel coordinate plots.

Time-Tubes: Visual fusion for ameliorating uncertainty of blazar datasets from different observatories

SAWADA Naoko, NAKAYAMA Masanori, YUN Hsiang-Yun, UEMURA Makoto, FUJISHIRO Issei

Proceedings of IEEE PacificVis 2017 (IEEE Computer Society) 336 - 337 2017.04

Research paper (international conference proceedings), Joint Work, Accepted

Blazars are active galactic nuclei whose relativistic jets ejected from the central black hole are pointing toward the Earth. Astronomers have attempted to classify blazars, whereas it is difficult to analyze the time-dependent multivariate datasets with the conventional visualization methods, such as animeted scatterplot matrices. In our previous study, a new visualization scheme, called TimeTubes, was proposed, which allows the astronomers to analyze dynamic changes in and feature causality among the multiple time-varying variables. In this poster, we present a core idea to ameliorate data-inherent and mapping-inherent uncertainty through visual fusion of datasets for the same blazar from two different observatories.

Selection of localized audio track based on eye-tracking technologies with application to musical art gallery

SHIMIZU Fumiya, FUJISHIRO Issei

Proceedings of the 5th International Workshop on Image Electronics and Visual Computing (IEVC2017) (IIEEJ) 2017.03

Research paper (international conference proceedings), Joint Work, Accepted

Many methods using eye tracking have been proposed for realizing interfaces for everyday device including digital signage and HMD. Such visual interfaces have a potential to be utilized as audio interface. We herein intend to allow the viewer to select the audio data by detecting his/her gaze with a single webcam. As a result, we will be able to provide the viewer with an immersive environment where he/she can focus on the object easily. Also, we present a preliminary design of the interface with motivation for application to a museum or an art gallery.

A visual analysis system for compositional processes of spectral school

TAKAKURA Yuriko, NAKAYAMA Masanori, FUJISHIRO Issei

Proceedings of the 5th International Workshop on Image Electronics and Visual Computing (IEVC2017) (IIEEJ) 2017.03

Research paper (international conference proceedings), Joint Work, Accepted

We propose a visual analysis approach to explore the compositional process of composers in Spectral School, with a particular focus on the sub-processes of sound analysis and synthesis. Spectral music is one of the significant trends in contemporary music since the 1970s. Composers in Spectral School use the acoustic properties of sound spectra as the basis of their compositional materials. One of the representative software systems they use is AudioSculpt, which has been developed by IRCAM. We have developed an accompanying system with AudioSculpt to represent the history of creating sounds with spectral analysis of sound materials and processing of sound spectra using the various filters. The salient feature of the system lies in its stacked spectrogram space whose axes represent the elapsed time of the sound and the progress of composition. On the pixeloriented spatial substrate, the system makes it possible for users to analyze the compositional processes by dedicated interactive manipulations. As such, the users are allowed to examine the compositional processes of musical pieces, whereas primary targets of most previous studies were only completed pieces. The present system can also be regarded as an initial attempt at managing the provenance of timeseries events in music visualization field. Our approach is intended to open a door for the composers to develop and share the compositional methodologies.

Multisensory realization using topology-accentuated visualization

TAKESHIMA Yuriko, FUJISHIRO Issei

Proceedings of the 5th International Workshop on Image Electronics and Visual Computing (IEVC2017) (IIEEJ) 2017.03

Research paper (international conference proceedings), Joint Work, Accepted

Computer visualization is widely used to analyze various phenomena in many areas. It is useful to explore the target dataset which has a few physical fields, but it is hard to understand multiple fields simultaneously. Especially, in
flow fields, since most datasets have vector field and its associated multiple scalar fields, we are faced with the above problem as long as we rely only on visualization. In this
paper, we focus on a multisensory realization method that combines haptization with visualization for the analysis of flow fields. We propose the use of adaptive visual transfer
functions which are based on the topological structure of a target scalar field. Haptic transfer functions, which produce three-dimensional forces, are designed to analyze the vector
field in a haptic manner. We evaluate the effectiveness of our method using a time-varying three-dimensionalwake turbulence dataset.

Effects of non-contact interaction on digital signage advertisement

NAGAO Ken, FUJISHIRO Issei, TAKAHASHI Ikuo

Proceedings of the 5th International Workshop on Image Electronics and Visual Computing (IEVC2017) (IIEEJ) 2017.03

Research paper (international conference proceedings), Joint Work, Accepted

Nowadays a variety of interaction technologies have been developed and some of them allow a user to interact in non-contact ways such as through body gestures. Such non-contact interactions become to be utilized for wide purposes, including communication with digital signage, which is one of the new types of media and often used as advertisements in public. However, current utilization of non-contact interactions for digital signage advertisements lacks consideration of its effects from the aspect of consumer behaviors. In this paper, we study the effects of non-contact interactions on digital signage advertisements through hypothesis testing in the light of consumer behaviors. Our results suggest the pros and cons of non-contact interactions for digital signage advertisements. We discuss how we can capitalize the strengths of non-contact interactions for digital signage advertisement.

2D fluid shape design by direct manipulation

HAYAKAWA Yuta, FUJISHIRO Issei

Proceedings of the 5th International Workshop on Image Electronics and Visual Computing (IEVC2017) (IIEEJ) 2017.03

Research paper (international conference proceedings), Joint Work, Accepted

Human-body modeling and position specification for forensic autopsy data visualization

MANO Junki, TOYOURA, MAO Xiaoyang, SHOJO Hideki, ADACHI, FUJISHIRO Issei

Proceedings of the 5th International Workshop on Image Electronics and Visual Computing (IEVC2017) (IIEEJ) 2017.03

Research paper (international conference proceedings), Joint Work, Accepted

This paper proposes the methods for creating a human-body model that reflects individual victim characteristics and obtaining position information on the human-body model for the purpose of forensic autopsy data visualization. Although modern imaging technologies, such as CT and MRI, make it possible to obtain fine volumetric human-body model, these technologies are still not widely used in the real forensic autopsy sites due to the cost. To enable a forensic specialist to easily create 3D models of victims, we propose a new method which uses an affordable depth-sensing camera and requires few user interactions. To visualize the autopsy data directly on a 3D model, we also propose a method for specifying a position on the 3D model without impeding the progress of the autopsy procedure.

A recursive procedure model for improving appearance of clothes with fiber-level details

IKEDA Yasunari, FUJISHIRO Issei

Proceedings of the 5th International Workshop on Image Electronics and Visual Computing (IEVC2017) (IIEEJ) 2017.03

Research paper (international conference proceedings), Joint Work, Accepted

Making realistic yarn objects, a common material for textile, without losing details is a challenging issue. Recent methods for modeling yarn can be classified into two categories: volume-based methods and fiber-based ones. Among them, one of the latest fiber-based methods attempts to reconstruct twisted fibers from CT (Computed Tomography) images to improve the details of yarn models. While this method dramatically improves the details, mainly because of the limited resolution of the CT scanner, the fluff and fuzz of the yarn still cannot be obtained. Our goal is to realize the fluff and fuzz of yarn. To that end, we developed an extension method to attach microfibers to each fiber of the yarn. The method approximates the distribution of microfibers by recursively using statistical data. In this paper, we discuss the preliminary design of the method.

Parameter-setting for topology-accentuated transfer function for volume raycasting

TAKESIMA Yuriko, TAKAHASHI Shigeo, FUJISHIRO Issei

Proceedings of Seventh International Workshop on Topological Methods in Visualization (TopoInVis2017) 2017.02

Research paper (international conference proceedings), Joint Work, Accepted

The design of automatic transfer functions for volume rendering is a perennial problem in volume visualization. For the last two decades, a variety of design methodologies has been proposed. However, sensitive adjustment of related
control parameters remains entrusted to users, because rendering conditions such as the size of a target dataset and sampling distance of ray casting differ on a caseby-
case basis. Our group proposed one-dimensional transfer functions to accentuate topological changes in the scalar field of the target dataset. However, the method forces us to determine the actual control parameter values for the transfer functions in an empirical manner. In this extended abstract, we propose a supplementary mechanism to judiciously define an appropriate profile of opacity values. In our approach, the height and width of the hat functions to accentuate feature isosurfaces are determined according to the number of voxels belonging to the relevant topologically equivalent scalar field interval. The feasibility of the proposed method is evaluated by application to three kinds of volume dataset.

空間局在オーディオの視線追跡選択：エンタテイメント応用に向けて

清水文也，藤代一成

画像関連学会連合会第3回秋季大会予稿 (画像関連学会連合会) 2016.11

Research paper (conference, symposium, etc.), Joint Work

デジタルサイネージやヘッドマウントディスプレイなど, さまざまな日常生活レベルのデバイスのインタフェースとして視線追跡を利用する手法が数多く研究されている. 一方で, 視覚インタフェースはオーディオとの融合にも大いに可能性があると考えられる. 本研究では, 一般的なカメラを1 台だけ用いて得られたユーザの視線方向によって, 再生するオーディオデータを選択可能にする手法を提案する. 視線追跡をベースとしたオーディオインタフェースを開発することで, ユーザが対象物に集中しやすい環境を作り出し, 臨場感を提供する
ことを目的とする. また，美術館における予備実験や博物館のオーディオガイドへの適用を前提とした予備実験を行う.

呼吸動作キャプチャによる生命感の表現：ボーンモデルから3Dメッシュモデルへの拡張に向けて

清水貴大，中山雅紀，藤代一成

画像関連学会連合会第3回秋季大会予稿 (画像関連学会連合会) 2016.11

Research paper (conference, symposium, etc.), Joint Work

運動中の呼吸データをキャプチャし，そのデータを適用したアニメーションを作成する．本研究では，モーションデータに合わせて実際に運動し，その時の呼吸動作をキャプチャする．この2 つのデータを，3D アバタへの前段階として，肺・横隔膜モデルを付与した拡張ボーンモデルに適用し，呼吸データを適用していないボーンモデルに比べて，力感や間合いの表現が向上したアニメーションを作成する．さらに，そのアニメーションを3D メッシュモデルへ拡張する方法を提案する．

マーチングバンドにおける演奏者個人を対象とした移動経路の計量可視化

堀井絵里，藤代一成

NICOGRAPH2016 (芸術科学会) 119 - 120 2016.11

Research paper (conference, symposium, etc.), Joint Work, Accepted

吹奏楽活動のなかには，演奏者が演奏しながら定められた経路に従って歩くことにより隊形を作る，マーチングという演奏行為が存在する．本ポスタでは，市販のビデオカメラにより撮影されたマーチングの動画像から，演奏者の移動経路の精度を視覚的に解析するシステムを提案した．本システムは，動画像に映っている演奏者個人の移動経路を，物体追跡アルゴリズムを用いて同定し，さらにその演奏者が歩くべき経路と実際の経路を照らし合わせることにより，誤差を表示する．演奏者の選択や，移動経路が可視化された動画像の再生は，専用ユーザインタフェースを介して容易に実行できる．対象とする演奏者が他の演奏者や楽器により遮蔽された場合でも，その演奏者が動画像に再び現れるまで，それまでの移動ベクトルを用いて位置を推測することにより頑健に追跡を続ける．本システムにより演奏者は自分の改善点を知ることができ，その結果マーチング中の隊形の完成度を高めることが可能となった．

直接操作による2次元流体の簡易形状設計

早川雄登，藤代一成

NICOGRAPH2016 (芸術科学会) 115 - 116 2016.11

Research paper (conference, symposium, etc.), Joint Work, Accepted

直接操作によって2次元流体を簡易に作成できるインタフェースを提案した．本ポスタでは，流体シミュレーションおよび流体制御に用いるパラメータ調整を特定のモーションデータに対応させた直接操作によって，直感的な流体制御を試みた．これにより，流体シミュレーションの知識を必要とせず，2 次元流体を簡易に形状設計することが可能となった．モーションデータの取得には，Leap Motion を用いた．特定のモーションデータをコマンドとして識別し，2次元空間上でコマンドに応じた流体シミュレーションを実行した．

3次元頭髪モデルにおけるブリーチのビジュアルシミュレーション

堀江康晃，藤代一成

NICOGRAPH2016 (芸術科学会) 117 - 118 2016.11

Research paper (conference, symposium, etc.), Joint Work, Accepted

頭髪の色を変えるヘアカラーリングは, 施術後の髪色を事前に見ることができないため, 想像していたものとはかけ離れた髪色になることが多いという問題が生じる. 本研究では, ヘアカラーリングのなかでも毛髪の色を脱色するブリーチという方法を対象とし, ユーザがブリーチを行う時間を指定することで, 施術後の髪色を3D頭髪モデルにより提示することを目的とする. 毛髪の色が2種類のメラニン色素の量により決定する事実に着目し, そのメラニン量を表すパラメタを物理ベースの頭髪シェーディングモデルに組み込み, このパラメタ値により頭髪の色を操作可能にした. そして, 実際の毛髪のブリーチ実験による髪色変化量データをもとにメラニンパラメタ値を変化させることで, ブリーチによる頭髪の色変化を写実的に表現するビジュアルシミュレーションを実現した.

Visual analysis of rugby matches: Pixel-oriented visualization and evaluation indices

ISHIKAWA Yusuke, FUJISHIRO Issei

Proceedings of IEEE VIS2016 Posters (IEEE Computer Society) 2016.10

Research paper (international conference proceedings), Joint Work, Accepted

SeeGroove2: An orbit metaphor for interactive groove visualization

JIN Norihiko, HAGA Naoki, FUJISHIRO Issei

Proceedings of 2016 International Conference on Cyberworlds (IEEE Commputer Society) 131 - 134 2016.09

Research paper (international conference proceedings), Joint Work, Accepted

Groove, the sense of rhythmic feel or musical swing, is one of the most essential factors of a good musical performance.
Groove visualization can help players/listeners acquire groove sensation and share impressive expressions of music, regardless of personal hearing ability or musical sense. In this paper, we present SeeGroove2 as an extension of our previous system SeeGroove, by featuring a new groove visualization scheme relying on an orbit metaphor. Rhythm patterns are visually interpreted as various orbital shapes by plotting each played note as an orbiting circle and smoothly interpolating them. Thanks to the adoption of a module-oriented and multi-threaded architecture, the system can change the orbit shapes interactively as the music performance progresses, and thereby the user can feel groove transitions in the music on the fly.

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An affective video generation system supporting impromptu musical performance

KOBAYASHI Anri, FUJISHIRO Issei

Proceedings of 2016 International Conference on Cyberworlds (IEEE Commputer Society) 17 - 24 2016.09

Research paper (international conference proceedings), Joint Work, Accepted

When a musical instrument player performs music, the accompanying visual information can have a significant effect on the performance. For example, several players in a
jam session may change their style of playing immediately by closely examining the co-players’ expressions and behaviors and predicting their emotion and intention on the fly. In this paper, we propose a system that generates videos in response to the impromptu performance of a single musical instrumental player. The system evaluates the input signals in an affective way and generates a corresponding video based on the results of the evaluation. The player tends to change his/her performance while being inspired by the generated video and giving further triggers for the system to modify the video. The system aims to establish such an affective loop, where it is expected to act as a “co-player” who continues having an influence on the performance of the real player. The final goal of this study is to improve the quality of the player’s performing experience through such interactions between the player and the system. By conducting a user evaluation, it was proven that we were able to inspire an amateur guitarist as the subject through the affective video generation and provide a cyberworld where he is allowed to experience a better performance than playing alone.

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ビジュアル情報処理のパイプラインと研究スパイラル再考

FUJISHIRO Issei

映像情報メディア学会技術報告 (映像情報メディア学会) 40 ( 7 ) 9 - 10 2016.08

Research paper (conference, symposium, etc.), Single Work, ISSN 1342-6893

本講演は，2016年8月26日に北海道函館市公立はこだて未来大学で開催された画像電子学会第278回研究会（共催：映像情報メディア学会映像表現&コンピュータグラフィックス研究会）の招待講演である．ここでは，具体的なビジュアル情報処理の研究事例を参照し，視覚データの生産から消費までパイプラインを拡大するとともに，20年周期の研究スパイラルを意識することの学術的意義について平易に解説した．

LMML: Describing injuries for forensic data visualization

BOUSSEJRA Malik Olivier, ADACHI Noboru, SHOJO Hideki, TAKAHASHI Ryohei, FUJISHIRO Issei

Proceedings of NICOGRAPH International 2016 (IEEE Computer Society) 153 - 153 2016.07

Research paper (international conference proceedings), Joint Work, Accepted

Justice needs efficient tools to exact an accurate and fair
judgment. Our research aims at developing a subset of those
tools for storage and utilization of autopsy data (autopsy
being the medical examination to identify the cause of death, through LMML, the Legal Medicine Mark-up Language,
a mark-up language whose syntax and semantics are designed
according to the operative procedure certified by the
Japanese Society of Legal Medicine. Using an interface we
developed, the user (i.e. a medical examiner, a prosecutor or a lawyer) can manage, create, edit LMML files and output
autopsy visualizations. The scope of this poster was focused on how injuries are described within the framework.

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TimeTubes: Design of a visualization tool for time-dependent, multivariate blazar dataset

XU Longyin, NAKAYAMA Masanori, WU Hsiang-Yun, WATANABE Kazuho, TAKAHASHI Shigeo, UEMURA Makoto, FUJISHIRO Issei

Proceedings of NICOGRAPH International 2016 (IEEE Computer Society) 15 - 21 2016.07

Research paper (international conference proceedings), Joint Work, Accepted

Blazars are active galactic nuclei whose relativistic jets ejected from the central black hole are pointing toward the Earth. Astronomers have attempted to classify blazars, but analyzing the time-dependent multivariate datasets with conventional visualization methods, such as scatter plot matrices, is difficult. This paper presents TimeTubes, a new visualization scheme that allows astronomers to analyze dynamic changes in and feature causality among the multiple time-varying variables. We target six representative time-varying variables from the originals, including two polarization-related parameters and their corresponding errors, intensity, and color. The four polarization parameters with a common time stamp are transformed to an ellipse, and a series of such ellipses are aligned in parallel along the time line to form a volumetric tube in 3D space. The resulting tube is then colorized by the
observed intensities and colors of the blazar. We designed a
designated interface with nine functions to control the view of the tube interactively. The usability of TimeTubes was discussed with feedback from astronomers.

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LMML: Initial developments of an integrated environment for forensic data visualization

BOUSSEJRA Malik Olivier, ADACHI Noboru, SHOJO Hideki, TAKAHASHI Ryohei, FUJISHIRO Issei

EuroVis 2016 - Short Papers (The Eurographics Association) 2016.06

Research paper (international conference proceedings), Joint Work, Accepted

Fighting against crime is paramount to any society, maybe more today than ever before. Tools to fight and elucidate crime are rooted in forensic science. Through the autopsy of a body, we can answer a whole range of questions as to how death happened and come up with explanations and counter-measures so that the same dire circumstance does not happen again. Now, because the reports collecting the data are written manually, the recording of the data collected through traditional autopsy still is a cumbersome, time-consuming task. Our framework, based on a mark-up language (that we dubbed ''LMML'') to store, describe and arrange forensic data, aims at overcoming those issues. Our contribution is twofold: the design of the syntax and semantics of LMML, and the conception of an interface to create, edit, analyse or query files written in that language. Thus, this framework allows quicker, smoother input of forensic data, for better automation and visualization thereof, so that they can be used by medical examiners, investigators, as well as judicial courts.

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Naked-eye 3D imaging through optical illusion using L-shaped display surfaces

ISAKA Takeru, FUJISHIRO Issei

The Journal of The Institute of Image Information and Television Engineers (The Institute of Image Information and Television Engineers) 70 ( 6 ) J143 - J146 2016.05

Research paper (scientific journal), Joint Work, Accepted, ISSN 1342-6907

安価ながら効果的な裸眼立体表示を可能にするディスプレイシステムの開発は，ビジュアルコンピューティング分野におけるきわめて重要な課題の一つである．ホログラフィに代表されるような，ハードウェアの描像原理を高度化することで発展してきた既存システムは，現時点では生成映像の品質を向上させにくいという課題がある．そこで本論文では，複数枚の汎用ディスプレイを直交に配置したL 字型の表示空間上で，陰影と運動視差を中心とする単眼性の奥行
き知覚要因を利用して，一般的な2D グラフィックスと同等の解像度と明度をもつ，個人向けの裸眼立体映像を手軽に生成する手法を提案する．ユーザの視線追跡により本手法の有効性を確認する予備的評価についても報告する．

複素パラメータによる平面曲線の解析的な延長についてとそのインタラクティブアートへの応用 —実世界は果たして高次元世界の断面になっているか？

宮澤篤，中山雅紀，藤代一成

日本図学会2016年度春季大会学術講演論文集 (日本図学会) 83 - 88 2016.05

Research paper (conference, symposium, etc.), Joint Work, ISSN 2189-0072

よく知られているように，方程式x^2+1=0は実数の範囲では解をもたない．そこで，関係式i^2+1= 0を満たすような虚数単位iを含むように数の次元を1つ上げて， a+ib の形の複素数を得たのであるが，たとえば交流回路のインピーダンス計算が複素数によって楽に行えることや，「虚数の光」ともよばれるエバネッセント（近接場）光が，マクスウェル方程式の平面波解（複素数で書かれる）として導かれることなど，「次元を上げると，こんなにいいことがある」例が数多く示されている．言い換えると，新しい理論やものの見方は，数理科学の視野を拡大するものでなければならないが，たとえそれらが合理的に有用なものとして受け入れられたとしても，そもそも2次元しか見えない3次元空間の住人が4次元以上の直積空間を理解しようとするのは容易なことではない．ここでは，4次元図形の直観像を得るための1つの方法として，複素初等関数の可視化と，その応用である「複素パラメータによる平面曲線の解析的な延長」について論じてみたい．

Asymmetric biclustering with constrained von Mises-Fisher models

WATANABE Kazuho, WU Hsiang-Yun, TAKAHASHI Shigeo, FUJISHIRO Issei

Jounal of Physics: Conference Series 1742-6596 (IOP Publishing) 699 ( 012018 ) 2016.04

Research paper (scientific journal), Joint Work, Accepted, ISSN 1742-6596

As a probability distribution on the high-dimensional sphere, the von Mises-Fisher (vMF) distribution is widely used for directional statistics and data analysis methods based on correlation. We considered a constrained vMF distribution for block modeling, which provides a probabilistic model of an asymmetric biclustering method that uses correlation as the similarity measure of data features. We derived the variational Bayesian inference algorithm for the mixture of the constrained vMF distributions. It was applied to a multivariate data visualization method implemented with enhanced parallel coordinate plots. This paper was presented at The International Meeting on High-Dimensional Data-Driven Science (HD3-2015), held in Kyoto in December 2015.

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Data-driven approach to Type Ia supernovae: Variable selection on the peak luminosity and clustering in visual analytics

UEMURA Makoto, KAWABATA Koji S., IKEDA Shiro, MAEDA Keiichi, WU Hsiang-Yun, WATANABE Kazuho, TAKAHASHI Shigeo, FUJISHIRO Issei

Journal of Physics: Conference Series (IOP Publishing) 699 ( 012009 ) 2016.04

Research paper (scientific journal), Joint Work, Accepted, ISSN 1742-6596

Type Ia supernovae (SNIa) have an almost uniform peak luminosity, so that they are used as "standard candle" to estimate distances to galaxies in cosmology. In this article, we introduced our two recent works on SNIa based on data-driven approach. The diversity in the peak luminosity of SNIa can be reduced by corrections in several variables. The color and decay rate have been used as the explanatory variables of the peak luminosity in past studies. However, it is proposed that their spectral data could give a better model of the peak luminosity. We use cross-validation in order to control the generalization error and a LASSO-type estimator in order to choose the set of variables. Using 78 samples and 276 candidates of variables, we confirmed that the peak luminosity depends on the color and decay rate. Our analysis does not support adding any other variables in order to have a better generalization error. On the other hand, this analysis is based on the assumption that SNIa originate in a single population, while it is not trivial. Indeed, several sub-types possibly having different nature have been proposed. We used a visual analytics tool for the asymmetric biclustering method to find both a good set of variables and samples at the same time. Using 14 variables and 132 samples, we found that SNIa can be divided into two categories by the expansion velocity of ejecta. Those examples demonstrate that the data-driven approach is useful for high-dimensional large-volume data which becomes common in modern astronomy. This paper was presented at The International Meeting on High-Dimensional Data-Driven Science (HD3-2015), held in Kyoto in December 2015.

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Enabling interactive scientific data visualization and analysis with see-through HMDs and a large tiled display

NAGAO Ken, YE Yucong, WANG Chuan, FUJISHIRO Issei, MA Kwan-Liu

Proceedings of IEEE VR2016 Workshop on Immersive Analytics (IEEE Computer Society) 2016.03

Research paper (international conference proceedings), Joint Work, Accepted

Validation and exploration of the data generated by large-scale scientific simulations rely on sophisticated visualization and analysis tasks. With the advancement of supercomputing, the growing scale and complexity of the data make some of these tasks challenging, which demands new hardware and software solutions. We believe it is possible to address some of the challenges by utilizing the increasingly affordable see-through head mounted display (HMD) devices together with a low-cost tiled HDTV display. With the tiled display to provide a high-resolution overview of the data, the user can freely choose a small area to explore and analyze using a see-through HMD in stereoscopic 3D with gesture input. During such local exploration and detail data analysis, the user can apply a newly derived visualization parameter setting to the large tiled display for a new overview. In this way, computational costs become more manageable because realtime rendering and response are only required to cover a small screen space and a subset of the data. In our current study, we focus on supporting immersive isosurface and streamline visualization and analysis of 3D flow field data. In this workshop paper, we presented our preliminary design and results, and we also discussed our further development and evaluation plan.

即興演奏に呼応するアフェクティブな映像生成システム

小林杏理，藤代一成

映像情報メディア学会技術報告 (映像情報メディア学会) 40 ( 11 ) 261 - 264 2016.03

Research paper (conference, symposium, etc.), Joint Work

本稿では, 即興演奏を行う楽器演奏者を対象ユーザとして, その演奏情報をリアルタイムに読み取り, それに呼応して映像生成を行うシステムを提案した. 提案システムでは, 演奏者の演奏をアフェクティブな評価基準をもって評価し, その結果に応じて映像生成を行い, 演奏者にインスピレーションを与えることを目指す. インスピレーションを得た演奏者が演奏を変化させ, またシステムはそれに呼応し映像を変化させるという, アフェクティブな表現のループを形成することで, 演奏者の「共演者」としての役割をシステムで再現することが, 本研究の目標である.

マルチスレッド設計によるインタラクティブなグルーヴ可視化

神展彦，芳賀直樹，藤代一成

映像情報メディア学会技術報告 (映像情報メディア学会) 40 ( 11 ) 1 - 4 2016.03

Research paper (conference, symposium, etc.), Joint Work

グルーヴとは，演奏における音のうねり，リズムのノリや⼀体感などを表す, よい演奏に必要不可欠な要素のひとつである．グルーヴ可視化は，音楽的センスや聴力の個人差によらないグルーヴの習得や音学経験に制限されない音楽の感動の共有など，さまざまな応用につながる．本稿では，MIDI 信号として入力された音楽をインタラクティブに図形に変換する，直感的なリズム可視化システムSeeGroove2を提案した．演奏された音符それぞれに対して点をプロットし，滑らかに補間することにより，リズムパターンを多様な形に表現する．演奏に対してインタラクティブに図形が変化するので，ユーザは音楽の移り変わりを視覚的に感じることができる．このインタラクティブ性は，1,920Hzで動作する入力系スレッドと60Hzで動作する計算・描画系スレッドのマルチスレッド設計によって実現されている．

薄膜と液状内容物との双方向連成を考慮した破裂のビジュアルシミュレーション

佐原淳允，藤代一成

映像情報メディア学会技術報告 (映像情報メディア学会) 40 ( 11 ) 37 - 40 2016.03

Research paper (conference, symposium, etc.), Joint Work

風船やクッションなどの薄膜で覆われたオブジェクトの破裂表現は，日常頻繁に見られる現象であるが，正確にモデリングされた例はまだ報告されていない．そこで本研究では，破裂を『薄膜に拘束されていた液状内容物が，薄膜の破壊によって流出し，飛沫を発生させながら飛び散る』現象と定義し，モデリングを試みた．特に，内容物から薄膜への影響だけでなく，薄膜から内容物への影響も正確に表現する双方向のモデルの構築を目指す．具体的なシミュレーション手法として，薄膜を三角形要素，内容物を四面体要素で記述し，応力の計算に有限要素法を使用する．本研究のモデルでは，メッシュの境界面が陽に構築されているため，衝突や摩擦などの表面の相互作用の計算を厳密に定義することができる．また，各タイムステップの最後には，計算精度の向上や，もっともらしい破片生成のために要素のリメッシングを行う．提案手法では，薄膜の破壊が引き金となり，破裂が発生するという，既存の数値計算モデルでは表現できない現象をシミュレーションすることが可能であることを，実物の高速撮影ビデオとの定性的比較により明らかにした．

作曲家の変奏特徴を理解するための変奏曲可視化システム

村岡遼太，藤代一成

映像情報メディア学会技術報告 (映像情報メディア学会) 40 ( 11 ) 89 - 92 2016.03

Research paper (conference, symposium, etc.), Joint Work

変奏曲とは，主題とよばれる簡単な旋律と主題を様々に変化させた変奏からなるクラシック音楽の楽曲形式の一つである．変奏曲を理解する際には，主題がどのように変化しているかを把握することが重要であるが，楽器経験者でも楽譜や音源のみから主題の変化の様子を読み取ることは困難である．そこで本研究では，楽器の演奏者や，音楽は聴くが演奏経験はないといった音楽愛好家に対して，変奏曲の構造を可視化するシステムを開発した．本システムは，入力をMIDI データとし，3 次元空間にオブジェクトを配置することで可視化する．その際，用いられている変奏様式によりオブジェクトの色や形状を変化させることでどのような変奏がなされてかを表現している．また，ユーザがより変奏曲の構造を理解しやすくするよう対話的視覚情報探索機能を提供する．システムの性能を評価するにあたり，マッピングのわかりやすさ，楽譜と本システムを用いた際の変奏曲の理解度についての実験を行い，本システムが変奏曲の構造理解に有効であることが示された．

非一様な密集度を考慮した群衆移動のモデリング

鈴木涼平，藤代一成

映像情報メディア学会技術報告 (映像情報メディア学会) 40 ( 11 ) 127 - 130 2016.03

Research paper (conference, symposium, etc.), Joint Work

群衆の動きに対する研究は，古くは人間の認知に関する研究から始まり，今日に至るまで発展を続けてきている．群衆の動きを自動生成するモデルに対する需要は幅広く，娯楽志向のものに目を向けると，多様なシーンに対して，尤もらしい人の動きを高速に計算できるモデルが求められている．本稿では，リアルタイム性が必要となる状況下で，人の動きに関してユーザが満足できる品質を達成するため，カット割りができない状況でも，シーンを占める群衆の密集度が大幅に変化しても，頑健かつ高速な動作を保証できる，群衆移動のモデルを提案した．このモデルでは，個人としての人の動きだけではなく，近しい関係の人によって形成される，2～3人の小集団の動きも扱うことで，より尤もらしい群衆移動を自動生成する．

An object space anti-aliasing method for shadows of hair-shaped objects

IKEDA Yasunari, MATSUOKA Toru, FUJISHIRO Issei

The IEICE Transactions on Information and Systems (IEICE) J99-D ( 3 ) 307 - 316 2016.03

Research paper (scientific journal), Joint Work, Accepted, ISSN 1881-0225

In this paper, we focus our attention to the shadow of hairs, which are vital to human animation, but are not easy to be accompanied by their stable shadows. Temporal-aliasing artifacts could be alleviated by image-space post-processing such as neighboring pixel averaging, though the quality depends strongly on the density of projected pixels. We therefore proposed an object-space anti-aliasing method by approximating the 3D shape of hair with a cloud of variable-size square splats with concentric opacity distribution. Empirical evaluation revealed that the proposed method outperforms the existing image-space
anti-aliasing with minimum loss of computational speed.

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Volume preserving viscoelastic fluids with large deformations using position-based velocity corrections

TETSUYA Takahashi, DOBASHI Yoshinori, FUJISHIRO Issei, NISHITA Tomoyuki

The Visual Computer (Springer-Verlag) 32 ( 1 ) 57 - 66 2016.01

Research paper (scientific journal), Joint Work, Accepted, ISSN 0178-2789

We proposed a particle-based hybrid method for simulating volume preserving viscoelastic fluids with large deformations. Our method combines smoothed particle hydrodynamics (SPH) and position-based dynamics (PBD) to approximate the dynamics of viscoelastic fluids. While preserving their volumes using SPH, we exploit an idea of PBD and correct particle velocities for viscoelastic effects not to negatively affect volume preservation of materials. To correct particle velocities and simulate viscoelastic fluids, we use connections between particles which are adaptively generated and deleted based on the positional relations of the particles. Additionally, we weaken the effect of velocity corrections to address plastic deformations of materials. For one-way and two-way fluid-solid coupling, we incorporate solid boundary particles into our algorithm. Several examples demonstrated that our hybrid method can sufficiently preserve fluid volumes and robustly and plausibly generate a variety of viscoelastic behaviors, such as splitting and merging, large deformations, and Barus effect.

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Development of a pants pattern design system based on 3D body data analysis

YAMAMOTO Takami, NAKAYAMA Masanori, KATSURA Rui, SAKAMOTO Akira, FUJISHIRO Issei

Transactions on Image Electronics and Visual Computing (IIEEJ) 3 ( 2 ) 114 - 124 2015.12

Research paper (scientific journal), Joint Work, Accepted

In this paper, we proposed a pants pattern design system covering its highly precise application to pattern making by analyzing human body measurement data acquired with a 3D scanner. This system is characterized by: (1) being able to analyze data required for the design of pants patterns using an improved 3D human body measurement analysis application, and (2) being provided with automatic pants drafting functions installed in an apparel CAD system using 3D human body measurement data. As a result, individual 3D human body measurement data can be analyzed both accurately and rapidly, thereby enabling pants patterns that comfortably and properly fit the physique of the wearer to be obtained in a short period of time.

Ontology-supported design of visualization workflows in fluid science

TAKESHIMA Yuriko, FUJISHIRO Issei

Proceedings of ACM SIGGRAPH Asia 2015 Visualization in High Performance Computing (ACM, New York, NY, USA) 2015.11

Research paper (international conference proceedings), Joint Work, Accepted

Modular visualization environments (MVEs) are commonly used in many disciplines including fluid science. However, it is difficult for scientists and engineers, who are not necessarily visualization experts, to make full use of many built-in modules on the basis of their usability and interdependency for constructing optimal visualization workflows. In this paper, we presented a novel MVE, called goal-oriented application design guidance for modular visualization environments/flow visualization (GADGET/FV), that is designed and built on an ontological framework to assist users to design their flow visualization workflows. The system relies primarily on an extended Wehrend Matrix that allows users to specify their goals and requirements, and to search the knowledge-base for appropriate visualization workflows on their behalf. In addition, users can browse successful examples maintained in a case repository to facilitate their workflow design further; this concept is referred to as "design by example." In this paper, examples of three practical fluid analyses were presented to illustrate the usefulness of a prototype system. Furthermore, the extensibility of the system to handle large-scale datasets was discussed.

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Adsorptive SPH for directable bleeding simulation

UEDa Kazuhide, FUJISHIRO Issei

Proceedings of the 14th ACM SIGGRAPH International Conference on Virtual-Reality Continuum and its Applications in Industry (VRCAI 2015) (ACM, New York, NY, USA) 9 - 16 2015.10

Research paper (international conference proceedings), Joint Work, Accepted

We built upon SPH to devise a directable scheme for bleeding simulation that realistically represents adherence onto and streak formation on the skin surface in real time. To ensure compatibility of expressiveness and space & time efficiency, we judiciously designed four specific types of particles and their interactions and incorporated these elements into the SPH scheme. In-vivo particles obey a simple in-vivo blood flow model that can reflect both hemorrhage volume and blood pressure. The particles flowing out through the wound, called flow particles, manifest the primary behaviors of bleeding, including blood coagulation, blood adherence onto the skin surface, and streak formation on the skin surface. The scheme then involves transforming the flow particles adhered onto the skin surface into relatively small adhered particles and representing a thin, flat layer of adhered blood with anisotropic kernels. Guiding particles generated along user-input strokes play a distinct role in giving gravity, biased slightly by the guiding force, to the remaining flow particles and thereby allow the users to control the overall bleeding so that it follows the desirable traces.

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SeeGroove: Supporting groove learning through visualization

FUJISHIRO Issei, HAGA Naoki, NAKAYAMA Masanori

Proceedings of 2015 International Conference on Cyberworlds (IEEE) 189 - 192 2015.10

Research paper (international conference proceedings), Joint Work, Accepted

Groove is a global feature of music performance that generalizes the surges, propulsive rhythmic feel, dynamics, and togetherness of sound to reflect overall rhythmic pleasure. Groove is vital to a good performance, though it is claimed that consierable experience is needed to be accumulated for the expression of groove at will. In this work, we proposed a general visualization system, called SeeGroove, that allows performers to efficiently comprehend groove in various music genres. For each genre, the standard MIDI dataset was extracted from actual performances of professional players in advance. The system then takes the difference between an input data of performance and the standard of a chosen genre to quantify the degree of groove of the performance. To visualize the differences, the user is allowed to rely on any combination of two modes and two views of designated visualization in accordance with his/her preferences and target information.

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IFWB: A simple image-based modeling approach to breaking the “fourth wall”

ISAKA Takeru, FUJISHIRO Issei

The Journal of the Society for Art and Science (The Society for Art and Science) 14 ( 4 ) 150 - 159 2015.09

Research paper (scientific journal), Joint Work, Accepted, ISSN 1347-2267

This paper proposed IFWB (Instant Fourth Wall Breaker) as a novel image-based modeling system that can provide a user with a feeling of presence in the world of image he/she is seeing. The user is required to input only a single image with a sense of depth, and then IFWB augments its depth without any further input and allows him/her to walk through the world of image freely. We mainly target at light and compact devices such as smartphones and tablets in order for the user to use the system readily just like a camera anytime and anywhere.

Axis contraction of parallel coordinates using spectral graph analysis

NOHNO Koto, WU Hsiang-Yun, WAYANABE Kazuho, TAKAHASHI Shigeo, FUJISHIRO Issei

Journal of IIEEJ (IIEEJ) 44 ( 3 ) 447 - 456 2015.08

Research paper (scientific journal), Joint Work, Accepted, ISSN 0285-9831

Parallel coordinates is well-known as a popular tool for visualizing the underlying relationships among variables in high-dimensional datasets. This visualization technique is useful for visually understanding the degree of correlation between data samples in terms of two adjacent axes. However, this representation still suffers from distracting visual clutter especially when the numbers of data samples and their associated dimension become high, because the associated polyline samples intricately overlap with each other within the limited screen space. This paper presented a method of alleviating such visual clutter by contracting multiple axes through the analysis of correlation between every pair of variables. In this method, we first define the similarity between a pair of dimensions as the value of the correlation coefficient, and construct a subgraph from the complete graph through eliminating all the edges in that their absolute correlation coefficients are less than some threshold, and then reorder the multiple axes by projecting the nodes onto the primary axis obtained using the spectral graph analysis. This allows us to compose a dendrogram tree by recursively merging a pair of the closest axes one by one. Smooth animation of the
associated axis contraction and expansion has also been implemented to enhance the visual readability of behavior inherent in the given high-dimensional datasets. We also conducted a user study to investigate how the correlations among coordinate axes are better visualized using our approach.

Glasses-free 3D imaging by optic illusion with orthogonally-arranged multi-displays

井阪　建，藤代一成

Visual Computing/グラフィクスとCAD合同シンポジウム2015 DVD予稿集 (画像電子学会) 2015.06

Research paper (conference, symposium, etc.), Joint Work, Accepted

Motion puppetry taking skeletal similarity into account

KANEKO Norihide, TAKAHASHI Reo, FUJISHIRO Issei

Proceedings of the 28th International Conference on Computer Animation and Social Agents (CASA2015) (Computer Graphics Society) 2015.05

Research paper (international conference proceedings), Joint Work, Accepted

Motion retargeting is a well-known method for generating character animations in computer graphics, where the original motion of an actor can be transferred to an avatar with a different skeletal structure and/or limbs' length. A specific type of retargeting for manipulating various avatars interactively is referred to as puppetry. However, previous learning-based works of puppetry cannot be said to be fully interactive, or require a large amount of metadata about the avatar's skeleton as well as training data of motions. Thus, we attempted to integrate existing methods by taking into account skeletal similarity between an actor and his/her avatar, to come up with an interactive and intuitive motion retargeting method that only requires a relatively small amount of training animations together with simple input metadata. Moreover, by classifying avatar's body parts in a procedural manner, a more flexible motion puppetry was realized, where the system user is allowed to specify desirable part-to-part correspondences.

Implicit formulation for SPH-based viscous fluids

TAKAHASHI Tetsuya, DOBASHI Yoshinori, FUJISHIRO Issei, NISHITA Tomoyuki, LIN Ming C.

Computer Graphics Forum (Eurographics) 34 ( 2 ) 493 - 502 2015.05

Research paper (scientific journal), Joint Work, Accepted, ISSN 1467-8659

We proposed a stable and efficient particle-based method for simulating highly viscous fluids that can generate coiling and buckling phenomena and handle variable viscosity. In contrast to previous methods that use explicit integration, our method uses an implicit formulation to improve the robustness of viscosity integration, therefore enabling use of larger time steps and higher viscosities. We use Smoothed Particle Hydrodynamics to solve the full form of viscosity, constructing a sparse linear system with a symmetric positive definite matrix, while exploiting the variational principle that automatically enforces the boundary condition on free surfaces. We also proposed a new method for extracting coefficients of the matrix contributed by second-ring neighbor particles to efficiently solve the linear system using a conjugate gradient solver. Several examples demonstrated the robustness and efficiency of our implicit formulation over previous methods and illustrated the versatility of our method.

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Biclustering multivariate data for correlated subspace mining

WATANABE Kazuho, WU Hsiang-Yun, NIIBE Yusuke, TAKAHASHI Shigeo, FUJISHIRO Issei

Proceedings of IEEE Pacific Visualization Symposium 2015 (IEEE Computer Society) 287 - 294 2015.04

Research paper (international conference proceedings), Joint Work, Accepted, ISSN 2165-8765

Exploring feature subspaces is one of promising approaches to analyzing and understanding the important patterns in multivariate data. If relying too much on effective enhancements in manual interventions, the associated results depend heavily on the knowledge and skills of users performing the data analysis. This paper presented a novel approach to extracting feature subspaces from multivariate data by incorporating biclustering techniques. The approach has been maximally automated in the sense that highly-correlated dimensions are automatically grouped to form subspaces, which effectively supports further exploration of them. A key idea behind our approach lies in a new mathematical formulation of asymmetric biclustering, by combining spherical k-means clustering for grouping highly-correlated dimensions, together with ordinary kmeans clustering for identifying subsets of data samples. Lower dimensional representations of data in feature subspaces are successfully visualized by parallel coordinate plot, where we project the data samples of correlated dimensions to one composite axis through dimensionality reduction schemes. Several experimental results of our data analysis together with discussions were provided to assess the capability of our approach.

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Development of a Skirt Pattern Design System Based on 3D Human Body Measurement Data Analysis

YAMAMOTO Takami, NAKAYAMA Masanori, KATSURA Rui, SAKAMOTO Akira, FUJISHIRO Issei

The Journal of the Society for Art and Science (The Society for Art and Science) 14 ( 1 ) 9 - 19 2015.03

Research paper (scientific journal), Joint Work, Accepted, ISSN 1347-2267

This paper presents a design system encompassing the process from high-precision design to the production of a skirt prototype based on the deployment of design by analysis of 3D body data gathered with a 3D scanner. This system is characterized in that (1) it allows the generation of accurate reference cross-sectional data from polygonal data of the body according to an intended design, (2) automatic drawing functions by the draping method using a reference cross-sectional data, and (3) production of patterns capable of accommodating various body types , As a result, individual 3D body data analysis can be performed rapidly and wear comfortable skirt patterns that fit the body contours can be obtained in a shorter period of time.

骨格の類似度を考慮したモーションパペトリー

KANEKO Norihide,TAKAHASHI Reo,FUJISHIRO Issei

映像表現・芸術科学フォーラム2015 (映像情報メディア学会・画像電子学会・芸術科学会) 2015.03

Joint Work

SeeGroove：可視化を介したグルーヴの学習支援

HAGA Naoki,NAKAYAMA Masanori,FUJISHIRO Issei

映像表現・芸術科学フォーラム2015 (映像情報メディア学会・画像電子学会・芸術科学会) 2015.03

Joint Work

位置ベース力学に基づく布の折り目シミュレーション

KITAMI Sho,FUJISHIRO Issei

映像表現・芸術科学フォーラム2015 (映像情報メディア学会・画像電子学会・芸術科学会) 2015.03

Joint Work

マルチスコピックビューアとその選択的時空間ブラウジングへの応用

SANO Takahiro,FUJISHIRO Issei

映像表現・芸術科学フォーラム 2015 (映像情報メディア学会・画像電子学会・芸術科学会) 2015.03

Joint Work

Splashing liquids with ambient gas pressure

UEDA Kazuhide, FUJISHIRO Issei

Proceedings of ACM SIGGRAPH Asia 2014 Technical Briefs (ACM) 2014.12

Research paper (international conference proceedings), Accepted

Splashing occurs when a liquid drop hits the solid or fluid surface at a high velocity. The drop after the impact spreads and forms a corona with a thickened rim, which first develops annular undulations and then breaks into secondary droplets. We have many chances to see splashes in our daily life, e.g., milk crown, splashing paint, and raindrops falling onto a pool, whose characteristics of deformation have a significant impact on the visual reality of the phenomena. Many experimental studies have been conducted to find criteria on when splashing would occur, but the physical mechanisms of splashing are still not completely understood. It was only recently discovered that ambient gas pressure is a principal factor for creating such a splash. In this paper, therefore, we newly incorporate the ambient gas pressure effect into the Navier-Stokes equations through SPH fluid simulation for representing more accurate splashing dynamics. Our experiments demonstrated that the new approach requires very little additional computing cost to capture realistic liquid behaviors like fingering, which have not previously been attained by SPH nor most schemes for fluid simulation.

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変奏様式に着目した変奏曲の可視化システムの構築

村岡遼太，藤代一成

音楽情報科学研究会第105回研究発表会 (情報処理学会) 2014.11

Joint Work

変奏曲とは，主題とよばれる素材を示して，その後主題を変化させた変奏を複数並べていくクラシック音楽の形式の一つである．変奏は主題の各要素に対して行われるが，変奏様式によって主題がどのように変化しているかを判別するには音楽理論の知識が不可欠である．そこで本研究では，音楽知識をもたないユーザにも，変奏様式による主題の変化をわかりやすく提示することを目的として，変奏曲の構造を可視化する手法を提案する．入力にはMIDI(Musical　Instrument Digital Interface) データを用いて，変奏曲を3次元空間内に可視化し，構造をより理解しやすくするための対話的機能を提供するシステムを開発した．そこでは，各変奏様式と3 次元空間内のオブジェクトを対応付ける独自のマッピングを用いている．さらに独自のマッピングに関するユーザテストを行い，提案したマッピングの有効性が示された．

IFWB：没入型映像インスタントメーカ

ISAKA Takeru, FUJISHIRO Issei

NICOGRAPH2014 (芸術科学会) 2014.11

Joint Work

本論文では, 奥行きのある構図をもつ画像を1枚入力すると，ユーザ入力を必要とすることなく即座に3次元情報を付与し, ユーザ頭部の位置変化に合わせて変化する没入型映像を生成するシステムIFWBを提案する．実際のターゲット環境としてスマートフォンやタブレット端末などの軽薄短小なデバイスを想定しており, カメラと同じような感覚で, いつでもどこでも使うことができる.

Development of a pants pattern design system based on 3D human body measurement data analysis

YAMAMOTO Takami, NAKAYAMA Masanori, KATSURA Rui, SAKAMOTO Akira, FUJISHIRO Issei

Proceedings of the 4th IIEEJ International Workshop on Image Electronics and Visual Computing Workshop 2014 (IIEEJ) 4B-2 2014.10

Accepted

In this paper, we propose a pants pattern design covering its highly precise design to pattern making by analyzing human body measurement data acquired with a 3D scanner. This system is characterized by: (1) being able to analyze data required for the design of pants patterns using an improved 3D human body measurement analysis application, and (2) being provided with automatic pants drafting functions installed in an apparel CAD system using 3D human body measurement data. As a result, individual 3D human body measurement data can be analyzed both accurately and rapidly, thereby enabling pants patterns that are comfortable and properly fit the physique of the wearer to be obtained in a short period of time.

画像電子学会誌ビジュアルコンピューティング特集号

藤代一成（ゲスト編集委員長）

(画像電子学会) 2014.08

Mood-Learning Public Display: Adapting content design evolutionarily through viewers' involuntary gestures and movements

NAGAO Ken, FUJISHIRO Issei

IEICE Transactions on Information and Systems (IEICE) E97-D ( 8 ) 1991 - 1999 2014.08

Research paper (scientific journal), Joint Work, Accepted, ISSN 1745-1361

Due to the recent development of underlying hardware
technology and improvement in installing environments, public display has been becoming more common and attracting more attention as a new type of signage. Any signage is required to make its content more attractive to its viewers by evaluating the current attractiveness on the fly, in order
to deliver the message from the sender more effectively. However, most previous methods for public display require time to reflect the viewers' evaluations. In this paper, we present a novel system, called Mood-Learning Public Display, which automatically adapts its content design. This system
utilizes viewers' involuntary behaviors as a sign of evaluation to make the content design more adapted to local viewers' tastes evolutionarily on site. The system removes the current gap between viewers' expectations and the content actually displayed on the display, and makes efficient mutual transmission of information between the cyberworld and the reality.

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Toplologically-Based Visual Data Mining for 2D Unsteady Flow Fields

TAKESHIMA Yuriko, FUJISHIRO Issei, TAKAHASHI Shigeo, HAYASE Toshiyuki

The Journal of the Institute of Image Electronics Engineers of Japan (The Institute of Image Electronics Engineers of Japan) 43 ( 3 ) 357 - 366 2014.07

Research paper (scientific journal), Joint Work, Accepted, ISSN 1348-0316

Vortices can be considered as one of the most fundamental features of a fluid, and play an indispensable role in the understanding of dynamics of underlying flows. However, it is difficult to capture time-varying, complex vortex structures consistently with traditional trial-and-error visualization methods because flow fields are changing drastically in unsteady fluid datasets. In this paper, we therefore propose a topologically-based approach to visual data mining of unsteady flow field datasets. Since it is well-known that the vortex centers are located at local minima in the 2D associated pressure field, we identify their locations by extracting critical points of the field, segmenting it into sub-regions each of vortices using topological information, and trace the vortices in the unsteady datasets. In addition, we propose a novel transfer function design which employs constant hue assignment and a stepwise brightness setting for timeseries datasets. The design of transfer function allows users to understand the global change in the flow fields from the hue value as well as the behavior of the vortices even if the flow fields are changing drastically. The feasibility of our approach is illustrated with an application to practical datasets for Karman vortex street, which are taken from measurement-integrated simulation of the Hybrid Wind Tunnel.

Spectral-based contractible parallel coordinates

NOHNO Koto, WU Hsiang-Yun, WATANABE Kazuho, TAKAHASHI Shigeo,FUJISHIRO Issei

Proceedings of iV2014 (IEEE Computer Society) 7 - 12 2014.07

Research paper (international conference proceedings), Joint Work, Accepted

This paper presents a method of alleviating such visual clutter by contracting multiple axes through the analysis of correlation between every pair of variables. In this method, we first construct a graph by connecting axis nodes with an edge weighted by data correlation between the corresponding pair of dimensions, and then reorder the multiple axes by projecting the nodes onto the primary axis obtained through the spectral graph analysis. This allows us to compose a dendrogram tree by recursively merging a pair of the closest axes one by one. Our visualization platform helps the visual interpretation of such axis contraction by plotting the principal component of each data sample along the composite axis. Smooth animation of the associated axis contraction and expansion has also been implemented to enhance the visual readability of behavior inherent in the given high-dimensional datasets.

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Fast simulation of viscous fluids with elasticity and thermal conductivity using position-based dynamics

TAKAHASHI Tetsuya, NISHITA Tomoyuki, FUJISHIRO Issei

Computers & Graphics (Elsevier) 43 21 - 30 2014.07

Research paper (scientific journal), Joint Work, ISSN 0097-8493

In this paper, we propose a novel particle-based Lagrangian method for efficiently simulating viscous fluids by adopting position-based constraints. Our method uses the geometric configuration of particles for the positional constraints to approximate the dynamics of viscous fluids using position-based dynamics; thus the method can plausibly generate their motions while allowing for the use of much larger time steps than those previously adopted in the viscous fluid simulations. We also propose an associated boundary-handling scheme for position-based fluids to precisely specify boundary conditions for the constraints. Additionally, we reproduce elastic deformations of materials by controlling the constraints and incorporate thermal conduction into our framework to simulate resultant changes in particle properties and phase transition in the materials. By adjusting parameters, our method can encompass complex motions of fluids with different properties in a unified framework. Several examples demonstrate the effectiveness as well as versatility of our method.

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頭髪状物体の描画に対応するアンチエイリアシング処理されたリアルタイムシャドウイング

ISAKA Takeru, FUJISHIRO Issei, MATSUOKA Toru

Visual Computing/グラフィクスとCAＤ合同シンポジウム2014 (画像電子学会・情報処理学会・映像情報メディア学会) 2014.06

Joint Work

単一画像からの運動視差立体視の実現

ISAKA Takeru, FUJISHIRO Issei

Visual Computing/グラフィクスとCAＤ合同シンポジウム2014 (画像電子学会・情報処理学会・映像情報メディア学会) 2014.06

Joint Work

Topological approach to multisensory realization of wake turbulence

TAKESHIMA Yuriko, MISAKA Takashi, OBAYASHI Shigeru, HOLZ'APFEL Frank, KATO Hiroshi, TAKAHASHI Shigeo, FUJISHIRO Issei

Aviation 2014 (AIAA) 2014.06

Research paper (international conference proceedings)

A velocity correcting method for volume preserving viscoelastic fluids

TAKAHASHI Tetsuya, FUJISHIRO Issei, NISHITA Tomoyuki

Proceedings of CG International 2014 (Computer Graphics Society) 2014.06

Research paper (international conference proceedings), Joint Work, Accepted

Visual simulation of compressible snow with friction and cohesion

TAKAHASHI Tetsuya, FUJISHIRO Issei, NISHITA Tomoyuki

Proceedings of NICOGRAPH International 2014 (The Society for Art and Science) 35 - 42 2014.05

Research paper (international conference proceedings), Joint Work, Accepted

Accelerated viscous fluid simulation using position based constraints

TAKAHASHI Tetsuya, FUJISHIRO Issei

Proceedings of CAD/Graphics 2013 (IEEE) 260 - 267 2013.11

Research paper (international conference proceedings), Joint Work, Accepted

In this paper, we present a novel particlebased method for efficiently simulating viscous fluids using position-based constraints. Our method utilizes the geometric configuration of particles for the positional constraints in the position-based dynamics, and thus can generate visually-plausible behavior of viscous fluids, while allowing for the use of much larger time steps than the ones previously adopted in the viscous fluid simulations. An associated boundary handling scheme for the position-based fluids is also proposed to properly address constraints for density and viscosity distributions on
boundaries. In addition, by adjusting parameters of particles, our method can produce complicated dynamics of threads, sheets, and volumes of different viscosity values in a unified framework. Several examples demonstrate the efficiency as well as robustness and versatility of our approach.

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みずみずしい果実の対話的なCG表現

TAKEDA Tomoko, FUJISHIRO Issei

NICOGRAPH2013 (芸術科学会) 2013.11

Research paper (conference, symposium, etc.), Joint Work

3Dボディデータ分析に基づくスカート原型デザインシステムの開発

YAMAMOTO Takami, NAKAYAMA MASANORI, FUJISHIRO Issei, KATSURA Rui, SAKAMOTO Akira

NICOGRAPH2013 (芸術科学会) 2013.11

Research paper (conference, symposium, etc.), Joint Work

本論文では，3D スキャナから採取した3D ボディデータを分析することで，スカートの高精度な設計から，その展開に基づいたスカート原型作製までカバーするデザインシステムを提案する．本システムは，（1）人体のポリゴンデータから意図するデザインに沿った正確な基準断面データ生成可能，（2）3D 分析データによる立体裁断方式の自動作図機能という2 点の特長をもつ．これにより，個々の3Dボディデータが高速に分析でき，体型にフィットした着心地の良いスカート原型を短時間に得ることが可能となった．

Improving structured content design of digital signage evolutionarily through utilizing viewers' involuntary behaviors

NAGAO Ken, FUJISHIRO Issei

Proceedings of Cyberworlds 2013 (IEEE) 108 - 115 2013.10

Research paper (international conference proceedings), Joint Work, Accepted

Digital signage has been getting more popularity due to the recent development of underlying hardware technology and improvement in installing environments. Any signage is required to make its content more attractive to viewers by evaluating the current attractiveness on the fly, in order to deliver the message from the sender more effectively. However, most previous methods for signage require time to reflect the viewers’ evaluations. In this paper, we present a novel, viewer-adaptive digital signage displaying academic conference posters, which automatically learns what structure and content are being attractive through the viewers’ involuntary behaviors, and makes them more adapted to the viewers. This system takes away the current gap between viewers’ evaluations and the content actually displayed on digital signage, and makes efficient mutual transmission of information between the cyberworld and the reality.

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Understanding viewers’ involuntary behaviors for adaptive digital signage

NAGAO Ken, FUJISHIRO Issei

Symposium on Applied Perception 2013 (ACM) 2013.08

Research paper (conference, symposium, etc.), Joint Work

Digital signage has been getting more popular due to the recent development of underlying hardware technology and improvement in installing environments. In order to deliver a message from a sender effectively, it is necessary to check up viewers’ evaluations towards the content actually displayed by the digital signage and utilize the evaluations to make it more adapted to the local viewers’ tastes. In our study, we have attempted to take advantage of viewers’ involuntary behaviors. In front of digital signage, viewers involuntarily behave in various ways, and these behaviors come directly from their minds. Therefore, if digital signage can recognize these behaviors, it can understand viewers’ actual feelings towards digital
signage. In order to prove the effectiveness of the method, we have developed a system which displays academic conference posters and automatically makes their content adapted to local viewers. The system utilizes viewers’ involuntary behaviors, and makes use of a genetic algorithm for automatic updates of the content.

Ontology-based support of visualization workflow design for structural analysis

TAKESHIMA Yuriko, FUJISHIRO Issei

Transactions of 22nd International Conference on Structural Mechanics in Reactor Technology (SMiRT-22) (International Association for Structural Mechanics in Reactor Technology (IASMiRT)) Paper ID: 816 2013.08

Research paper (international conference proceedings), Joint Work, Accepted

Computer visualization has become a crucial component of data analysis, and so-called Modular Visualization Environments (MVEs) have been used in a variety of analytical disciplines. Even so, scientists and engineers who are not visualization experts have some difficulty in selecting and applying visualization techniques that best suit their purposes. To address this problem, we have extended our visualization ontology to develop a visualization system that helps the users select and execute suitable visualization techniques. In this paper, we attempt to further extend our ontology towards a particularly important domain of visualization: structural analysis. The resulting system uses a refined Wehrend
Matrix to represent users’ goals and requirements, and to search the knowledge-base for appropriate visualization workflows. The system also allows the users to browse successful examples maintained in the case repository, thereby supporting “design by example”. Three practical structural analysis examples are presented to illustrate the usefulness of our prototype system.

A GPU-accelerated Visual Simulator of Whirlwind

NAKAJIMA Satoshi, FUJISHIRO Issei

The Journal of the Institute of Image Electronics Engineers of Japan (IIEEJ) 42 ( 4 ) 505 - 508 2013.07

Research paper (scientific journal), Joint Work, Accepted

In this short paper, we report how we accelerated a visual simulator of whirlwind with a GPU. In the simulation part, precise simulation can be carried out even with a coarse grid by adding smallscale turbulence on each particle to air flow roughly computed using a grid-based method. We decided to parallelize the grid-based method using CUDA. The rendering part was also accelerated by applying GLSL shader programming to a simplified variant of particle-based volume rendering to delineate changes in the translucency of the whirlwind. The accelerated visual simulator possesses its own user interface, which takes full advantage of the obtained fast performance, to allow the users to interactively control the whirlwind’s trajectory and interactions with other objects.

虫食い跡をもつ葉テクスチャの生成手法の提案

KANEKO Norihide, FUJISHIRO Issei

Visual Computing/グラフィクスとCAD合同シンポジウム2013 (画像電子学会，情報処理学会，映像情報メディア学会) 2013.06

Research paper (conference, symposium, etc.), Joint Work

本発表では葉の経時的変化として葉の虫食い跡に着目し, 主要な葉脈をユーザの入力に沿わせるようにして生成する一方, 細かな葉脈を手続き的に生成することで, テクスチャとして入力された葉の葉脈に一致する葉脈モデルを作成した. 昆虫はかたい箇所を避けるようにして摂食活動を行うことから, 作成した葉脈モデルに対して靱性分布を適用し, 昆虫の摂食行動に関係する各種化学因子の影響と葉脈の高靱性箇所の回避を考慮した昆虫の行動プロセスモデルを構築し, 作成した葉脈モデル上で昆虫の摂食行動を再現することを試みた.以上の処理で作成した食害を受けた葉のマップと葉身のテクスチャを用いてさらに虫食い跡周辺からの水分の蒸発を考慮した枯化の処理を行うことで, より現実に即した葉のテクスチャを作成することが可能となった.

布における折り目生成のビジュアルシミュレーション

KITAMI Sho, FUJISHIRO Issei

Visual Computing/グラフィクスとCAD合同シンポジウム2013 (画像電子学会，情報処理学会，映像情報メディア学会) 2013.06

Research paper (conference, symposium, etc.), Joint Work, Accepted

「衣・食・住」の「衣」を構成する布の表現は, CG の分野においてさまざまな研究が行われてきた. 映像作品に生活感を与える要素として, 布のシミュレーションはひじょうに重要な研究分野であるといえる. しかし, 既存研究の多くは, 「いかに写実的な布を表現するか」に焦点が当てられており, 加工された, または生活のなかで使い込まれたような布の研究はあまり報告されていない. そこで本論文では, 布の折り目の動的な生成モデルを提案する.

基礎的リズムパターンにおけるグルーヴの可視化

HAGA Naoki, NAKAYAMA Masanori, FUJISHIRO Issei

Visual Computing/グラフィクスとCAD合同シンポジウム2013 (画像電子学会，情報処理学会，映像情報メディア学会) 2013.06

Research paper (conference, symposium, etc.), Joint Work, Accepted

演奏の質にかかわる高次な音楽特徴であるグルーヴとは, 楽曲におけるリズムや音のうねり, 乗りなどを包括した概念であり, よい演奏には不可欠の要素とされる. しかし, 演奏において自在にグルーヴを表現するためには, ひじょうに多くの音楽経験を積む必要がある.そこで本研究では, グルーヴを可視化することで, ユーザのグルーヴ学習をより効率的にするための手法を提案する. 具体的には, グルーヴの要素となる音楽パラメータと超楕円体のパラメータとを対応付ける独自のマッピングを行った. また, そのマッピングに基づき,MIDI を入力として超楕円体のアニメーションとストロボ写真風の静止画像を生成した.

3×3パネル分割法を用いた環境可視化システム

SANO Takahiro, FUJISHIRO Issei

Visual Computing/グラフィクスとCAD合同シンポジウム2013 (画像電子学会，情報処理学会，映像情報メディア学会) 2013.06

Research paper (conference, symposium, etc.), Joint Work, Accepted

画像から得られる情報は時にかなり断片的である. そのような画像群から被写体の本質を誤解なく感得するには,被写体を取り巻く状況全体に対する理解が必要となる. 本研究では, 被写体同士の関係を抽象的に表現する層状グラフを構築し, 画像データに収められた被写体の状況を大局的に可視化する. また, この層状グラフによって半構造画像データを統一的に扱うことで, その半構造性を補う. 層状グラフに配置された画像データの閲覧には, 縦横3×3の矩形領域に区切られた表示インタフェースを用いる.

CosmicAI: Generating Sky Images Through Content-Based Search,Flexible Composition,and Work Sharing

MITANI Takanobu, FUJISHIRO Issei

The Journal of The Institute of Image Information and Television Engineers (ITE) 67 ( 6 ) J180 - J185 2013.05

Research paper (scientific journal), Joint Work, Accepted, ISSN 1881-6908

We propose a novel system, called CosmicAI, for providing an intuitive and efficient way to synthesize 2D sky images. The system utilizes a collection of high-quality proprietary sky part images for backgrounds, clouds, and the moon, and allows the users to generate their own sky images effectively through attribute-based retrieval of these sky parts images and their flexible layout and natural composition based on a new cloud extraction algorithm and an original filter for partly-overlapping pixels. Its one click search and active composition play an important role for realizing rapid image synthesis. Moreover, CosmicAI is capable of collecting via the Internet and searching for composite works. This function promotes group works by giving incentives to users with unclear design motives for generating a wide variety of sky images.

A topologically-enhanced juxtaposition tool for Hybrid Wind Tunnel

TAKESHIMA Yuriko, FUJISHIRO Issei, TAKAHASHI Shigeo, HAYASE Toshiyuki

Proceedngs of IEEE Pacific Visualization Symposium 2013 (IEEE Computer Society) 113-120 2013.02

Research paper (conference, symposium, etc.), Joint Work, Accepted

We have developed a hybrid wind tunnel, where 2D measurementintegrated (MI) simulation, which utilizes actual data acquired from real air flow behind a square cylinder, plays an important role in improving the accuracy of the numerical analysis. The wind tunnel
requires an accompanying visual analysis tool with which we
can effectively peer into the relationships between the actual and simulated flow fields. In this paper, we attempt to exploit an augmented reality display to that end. The basic idea is to superimpose the computationally-visualized MI simulated pressure field onto the actual flow velocity structure physically-visualized with oil misttraced streaklines instantaneously. Spatial registration of these two visual sources is rather straight-forward since the fixed cylinder of the wind tunnel is easily identified, whereas visualizing the MI
simulated pressure field can be characterized with a sophisticated scheme based on differential topology. Considering the fact that vortex centers are located at local minima in the pressure field, and each minimum is surrounded by a derived topological feature called
ridge cycle, we can colorize the field adaptively and keep track of Karman vortex streets robustly, regardless of drastic change in the Reynolds number of the flow field.

Making digital signage adaptive through a genetic algorithm - Utilizing viewers’ involuntary behaviors -

NAGAO Ken, FUJISHIRO Issei

Proceedings of the International Conference on Computer Vision Theory and Applications 2013 (INSTICC) 2 54-59 2013.02

Research paper (conference, symposium, etc.), Joint Work, Accepted

Digital signage has been becoming more popular due to the recent development of underlying hardware technology and improvement in installing environments. In digital signage, it is important to make the content more attractive to the viewers by evaluating its current attractiveness on the fly, in order to deliver the message from the sender more effectively. Most previous works for this evaluation do not take the viewers’ feeling towards the content into account, and the content is improved manually if needed in an off-line manner. In this paper, we present a novel method which does not rely on such manual evaluation and automatically makes the content more adapted to the viewers. To this end, we take advantage of the viewers’ involuntary behaviors in front of the digital signage for online updates through the usage of a genetic algorithm.

Research Group Introduction: Fujishiro Laboratory, Department of Information and Computer Science, Faculty of Science and Technology, Keio University

FUJISHIRO Issei

The Journal of the Institute of Image Electronics Engineers of Japan (IIEEJ) 41 ( 4 ) 428 - 429 2012.08

Research paper (scientific journal), Single Work, Lead author, Corresponding author

第17回計算工学講演会報告

NISHIWAKI Shinji, YAMADA Takayuki, ADACHI Taiji, OKAZAWA Shigenobu, FUJISHIRO Issei

計算工学 (日本計算工学会) 17 ( 3 ) 38-40 2012.07

Research paper (scientific journal), Joint Work, ISSN 1341-7622

Optimizing point cloud geometry for 3D aerial display

FUJISHIRO Issei

Microsoft Research CORE7 Project Summary Booklet (Microsoft Japan, Tokyo) 21 - 23 2012.06

Research paper (other academic), Single Work, Lead author, Corresponding author

Realizing a truly three-dimensional (3D) display environment has been an ultimate goal of visual computing communities. Laser-Plasma Scanning 3D Display (LPSD) is one of the most advanced 3D aerial display devices, which can plot a unicursal series of illuminants freely in the air. Though the LPSD device has been repeatedly updated, even the latest version is only capable of drawing a dynamic object at a rate of 5,000 illuminants per second, purely due to the hardware constraint. If we plotted the illuminants at a regular interval with a constant brightness, it might possibly lead to the loss of geometry and/or surface texture of a designed object. In this project, therefore, we attempt to seek a software-based solution to ameliorate this problem by the control of the brightness and density of plotted illuminants in accordance with existing surface descriptors, to convey salient features of 3D shapes with even a limited number of illuminants.

芸術科学フォーラム2012報告

FUJISHIRO Issei

DiVA（芸術科学会誌） 28 3-4 2012.04

Research paper (scientific journal), Single Work

計算美学のすゝめ

FUJISHIRO Issei

DiVA(Digital,Interactive and Visual Arts) (The Society for Art and Science) 28 2 - 2 2012.04

Research paper (scientific journal), Single Work

可視化による知識発見のライフサイクル管理とその流動応用評価

FUJISHIRO Issei, HAYASE Toshiyuki, TAKESHIMA Yuriko

平成22年度共同利用・共同研究拠点「流体科学研究拠点」活動報告書 (東北大学流体科学研究所) ( J10037 ) 79-80 2011.10

Research paper (other academic), Single Work

Previewing volume decomposition through optimal viewpoints

TAKAHASHI Shigeo, FUJISHIRO Issei, TAKESHIMA Yuriko, BI Chongke

Scientific Visualization: Interactions, Features, Metaphors, Dagstuhl Follow-Ups (Dagstuhl Publishing, Germany) 2 Chapter 23 (346-359) 2011.10

Research paper (conference, symposium, etc.), Joint Work, Accepted, ISSN 1868-8977

Understanding a volume dataset through a 2D display is a complex task because it usually contains multi-layered inner structures that inevitably cause undesirable overlaps when projected onto the display. This requires us to identify feature subvolumes embedded in the given volume
and then visualize them on the display so that we can clarify their relative positions. This article therefore introduces a new feature-driven approach to previewing volumes that respects both the 3D nested structures of the feature subvolumes and their 2D arrangement in the projection by minimizing their occlusions. The associated process begins with tracking the topological transitions of isosurfaces with respect to the scalar field, in order to decompose the given volume dataset into feature components called interval volumes while extracting their nested structures. The volume dataset is then projected from the optimal viewpoint that archives the best balanced
visibility of the decomposed components. The position of the optimal viewpoint is updated each time when we peel off an outer component with our interface by calculating the sum of the viewpoint optimality values for the remaining components. Several previewing examples are
demonstrated to illustrate that the present approach can offer an effective means of traversing volumetric inner structures both in an interactive and automatic fashion with the interface.

SPH-based method for interactive flame simulation - Implementation on CPU and GPU

MABUCHI Satoshi, OHNO Yoshio, FUJISHIRO Issei

Proceedings of ASIAGRAPH2011 (Virtual Reality Society of Japan) 41-46 2011.10

Research paper (conference, symposium, etc.), Joint Work

In this paper, we propose a novel, particle-based flame simulation method, which relies on SPH to simulate the dynamics of flames by introducing a buoyancy term as an external force to the Navier-Stokes equations. The buoyancy term is directly affected by heat generated from a simple chemical reaction model. For efficiency, we adaptively re-sample particles around a flame. We demonstrate that it is possible to execute three-dimensional flame simulations in real-time for typical cases including transition from initial to stable states, and one-way coupling with solid. Our method offers reasonable results on CPU, while more realistic results can be obtained using GPGPU.

Measurement-integrated simulation and visualization of Karman vortex streets in Hybrid Wind Tunnel

TAKESHIMA Yuriko, FUJISHIRO Issei, TAKAHASHI Shigeo, HAYASE Toshiyuki

Proceedings of ASIAGRAPH2011 (Virtual Reality Society of Japan) 35-40 2011.10

Research paper (conference, symposium, etc.), Joint Work

We have developed a hybrid wind tunnel, where 2D measurement-integrated (MI) simulation, which utilizes actual data acquired from real air flow behind a square cylinder, plays an important role in improving the accuracy of its numerical analysis. The wind tunnel requires an accompanying visual analysis tool with which we can effectively peer into the relationships between the actual and simulated flow fields. In this paper, we attempt to exploit the augmented reality-style display technique to that end. The basic idea is to instantaneously superimpose the computationally-visualized MI simulated pressure field onto the actual flow velocity structure physically-visualized with oil mist-traced streak lines. Space registration of these two visual sources is rather straight-forward since the fixed cylinder of the wind tunnel is easily identified, whereas visualizing the MI simulated pressure field can be characterized with its sophisticated scheme based on differential topology. Considering the facts that vortex centers are located at local minima in the pressure field, and each minimum is surrounded by a derived topological feature called ravine cycle, we can colorize the field adaptively and keep track of Karman vortex streets robustly, regardless of drastic change in the Reynolds number of the flow field.

SPH-based Real-time Flame Simulation

MABUCHI Satoshi, FUJISHIRO Issei, OHNO Yoshio

Journal of IPSJ (IPSJ) 52 ( 10 ) 2965-2972 2011.10

Research paper (scientific journal), Joint Work, Accepted, ISSN 1882-7764

In this paper, we propose a novel particle-based flame simulation method, which relies on SPH to simulate the dynamics of flame by introducing a buoyancy term as an external force to Navier-Stokes equation. The buoyancy term is directly affected by heat generated from a simple chemical reaction model. Good interchangeability allows us to easily couple our method with existing SPH source codes. For efficient execution, we adaptively re-sample particles around flame. We demonstrate three-dimensional simulations in real-time for typical cases including transition from initial to stable states, and one-way coupling with solid.

GPU-Based Adaptive Visualization for Particle Systems

ODAGAWA Masato, TAKESHIMA Yuriko, FUJISHIRO Issei, KIKUGAWA Gota, OHARA Taku

Transactions of the JSME (in Japanese) (JSME) 77 ( 781 ) 1767-1778 2011.09

Research paper (scientific journal), Joint Work, Accepted

When visualizing large-scale particle systems, it is difficult to maintain adequate framerates because we have to render dynamic scenes with a large number of small spheres. For the control of trade-offs between the overall image quality and total rendering speed, we propose a new rendering scheme which uses a fast method based on shaded texture mapping and a high-quality implicit surface method in a combined way. The shaded texture mapping, which generates a pseudo-texture through alpha-blending a proper portion of template texture for shade and highlight onto a base spherical texture, can render a particle faster than the implicit surface method. However, a weakness of the texture mapping lies in its poor shading quality. In contrast, the implicit surface method is accurate enough for analyzing particle systems visually. Actual method to render each particle is decided according to the viewing distance; the high-quality method is chosen only when the distance is smaller than a threshold, to allow the user to observe the region of interest closely. We use a molecular dynamics simulation dataset to evaluate the effectiveness of our scheme empirically. In addition to this, we also consider the extensibility of our scheme in terms of framerate stability, scalability, and expressiveness.

Particle-Based Real-Time Flame Rendering

MABUCHI Satoshi, FUJISHIRO Issei, OHNO Yoshio

The Journal of the Institute of Image Electronics Engineers of Japan (IIEEJ) 40 ( 4 ) 541-548 2011.07

Research paper (scientific journal), Joint Work, Accepted, ISSN 0285-9831

In this paper, we propose a particle-based method for real-time flame rendering. In the field of visualization, particle-based volume rendering has been introduced for the purpose of previewing. Our method is a reasonably-simplified version of the particle-based volume rendering. Compared with previous flame rendering methods, both detail representation and controllability are sufficiently improved. In addition to this, it is easily implemented using standard APIs, and its fast enough rendering speed allows us to adjust environmental settings on the fly. Moreover, our method requires a few standard parameters as particle attributes, and thus it would be used in conjunction with existing particle simulators.

Design of Surface Descriptor for Rendering Snow-Covered Terrain

NAKATANI Ayaka, FUJISHIRO Issei, OHNO Yoshio

The Journal of the Society for Art and Science (The Society for Art and Science) 10 ( 2 ) 79-86 2011.06

Research paper (scientific journal), Joint Work, Accepted, ISSN 1347-2267

Seasonally-transient contrast between snow and mountain surfaces makes a big appeal to every viewer. Generally, when deciding how much snow covers the mountain, we need to take many climatological factors into account, and it is likely to complicate the rendering process. In this paper, we present a phenomenological model which easily depicts snow-covered mountains. Our method relies on our own surface descriptor, which is based primarily on Tangent Sphere Accessibility of smoothed height field, and also considers geometric features like azimuth direction and altitudes to a limited extent. The feasibility of the proposed method is illustrated through application to a real height map dataset.

Interpolating 3D diffusion tensors in 2D planar domain by locating degenerate lines

BI Chongke, TAKAHASHI Shigeo, FUJISHIRO Issei

6th International Symposium, ISVC 2010, Las Vegas, NV, USA, November 29-December 1, 2010, Proceedings, Part I (Lecture Notes in Computer Science) (Springer-Verlag) 6453 328-337 2010.11

Research paper (conference, symposium, etc.), Joint Work, Accepted

Interpolating diffusion tensor fields is a key technique to visualize the continuous behaviors of biological tissues such as nerves and muscle fibers. However, this has been still a challenging task due to the difficulty to handle possible degeneracy, which means the rotational inconsistency caused by degenerate points. This paper presents an approach to interpolating 3D diffusion tensors in 2D planar domains by aggressively locating the possible degeneracy while fully respecting the underlying transition of tensor anisotropy. The primary idea behind
this approach is to identify the degeneracy using minimum spanning tree-based clustering algorithm, and resolve the degeneracy by optimizing the associated rotational
transformations. Degenerate lines are generated in this process to retain the smooth transitions of anisotropic features. Comparisons with existing interpolation
schemes will be also provided to demonstrate the technical advantages of the proposed approach.

山岳形状における積雪量を決定するサーフェス記述子の提案

NAKATANI Ayaka, FUJISHIRO Issei, OHNO Yoshio

第26回NICOGRAPH論文コンテスト (芸術科学会) 2010.09

Research paper (conference, symposium, etc.), Joint Work

本論文では，山岳形状における積雪の様子を再現する現象学的モデルを提案する．ここでは，積雪の時間変化や山肌とのコントラストなどの美しさを手軽に表現し，しかも制御可能にすることを目的としている．山肌における積雪の度合いを決めるためには，その場所での気候や気象，雪の密度・粘性・固さなど，一般的に現実世界の多くの物理的ファクタを考慮する必要があるが，本手法では独自のサーフェス記述子を介することで積雪の現象学的再現を試みる．そのサーフェス記述子は，平滑化された高さ場におけるTangent Sphere Accessibility をベースに，方角や高度などの幾何学的条件を限定的に考慮している．本論文ではさらに，実際の標高データを用いた山岳形状に適用し，提案手法の視覚的効果を検証する．

大野義夫先生（慶應義塾大学）第9回CG Japan Awardを受賞

FUJISHIRO Issei

芸術科学会誌 (芸術科学会) ( 21 ) 10-11 2010.08

Research paper (scientific journal), Single Work

Perceptually-guided design of nonperspectives through pictorial depth cues

YOSHIDA Kenichi, TAKAHASHI Shigeo, ONO Hiroaki, FUJISHIRO Issei, OKADA Masato

Proceedings of the Seventh International Conference on Computer Graphics, Imaging and Visualization 173-178 2010.08

Research paper (conference, symposium, etc.), Joint Work, Accepted

Introducing distortions into perspective views is a popular
technique to direct our visual attention to specific objects, as seen in hand-drawn illustrations and cartoon animations. This type of image expression, called nonperspective projection, is feasible in visual communication, because the human visual system can reconstruct the target three-dimensional (3D) scene correctly provided that the corresponding image distortions are within a certain perceptual tolerance. In this paper, we develop a perceptual approach to guiding the
design of such nonperspective images by referring to the 3D
perception induced by pictorial depth cues. We formulate an
acceptable tolerance by investigating how we perceive image
distortion according to the change in the configuration of
depth cues. The obtained formulation is then incorporated
into our new algorithm, with which we can automatically
control plausible image deformation by simply modifying
the positions and sizes of specific objects in a scene.

可視化による知識発見のライフサイクル管理とその流動応用評価

FUJISHIRO Issei, HAYASE Toshiyuki, OOBAYASHI Shigeru, TAKESHIMA Yuriko

平成21年度公募共同研究報告書 (東北大学流体科学研究所) ( J09038 ) 79-80 2010.08

Research paper (other academic), Single Work

自己組織化単分子膜のための粒子配置設計支援システム

TAKESHIMA Yuriko, NIIZAKA Takuma, KIKUGAWA Gota, OHARA Taku, FUJISHIRO Issei

第38回可視化情報シンポジウム講演論文集 (可視化情報学会) 30 ( 1 ) 277 - 280 2010.07

Research paper (conference, symposium, etc.), Joint Work

Topologically-based haptization and visualization of wake turbulence datasets

TAKESHIMA Yuriko, FUJISHIRO Issei, TAKAHASHI Shigeo, OOBAYASHI Shigeru

DVD Proceedings of Image Electronics and Visual Computng 2010 (Institute of Image Electronics Engineers of Japan) 2010.03

Research paper (conference, symposium, etc.), Joint Work, Accepted

VIDELICETにおけるEFD/CFDデータの並置化

FUJISHIRO Issei

宇宙航空研究開発機構特別資料，JAXA-SP-09-002 (宇宙航空研究開発機構) 71-83 2010.01

Research paper (bulletin of university, research institution), Single Work, ISSN 1349-113X

画像における不連続性に対する視覚注意の仕組みに関する研究

FUJISHIRO Issei, TAKESHIMA Yuriko, TAKAHASHI Shigeo, YOSHIDA Kenichi

次世代融合研究システム（スーパーコンピュータ）利用研究成果報告書 (東北大学流体科学研究所未来流体情報創造センター) 12 48 - 52 2009.07

Research paper (other academic), Joint Work

仙台空港における後方乱気流の計測融合シミュレーション

三坂孝志，大林茂，藤代一成，竹島由里子，山田泉，奥野善則

次世代スーパーコンピューティング・シンポジウム 2008 資料集 63 - 64 2008.09

Research paper (conference, symposium, etc.), Joint Work, Accepted

Guest editors' Introduction: Visualization research is growing and expanding

MA Kwan-Liu, FUJISHIRO Issei, LI Hua

IEEE Computer Graphics and Applications (IEEE Computer Society) 28 ( 5 ) 22-23 2008.09

Research paper (scientific journal), Joint Work, Accepted

GPUによる拡散トラクトグラフィ法の高速化

鈴木靖子，竹島由里子，藤代一成

第３６回可視化情報シンポジウム講演論文集 (可視化情報学会) 28 ( 1 ) 83 - 84 2008.07

Research paper (conference, symposium, etc.), Joint Work

2次元投影図上の見えの操作に基づいた非透視投影の設計

YOSHIDA Kenichi, TAKAHASHI Shigeo, FUJISHIRO Issei, OKADA Masato

画像電子学会誌 (東京・画像電子学会) 37 ( 4 ) 412-418 2008.07

Research paper (scientific journal), Joint Work, Accepted, ISSN 0285-9831

一般的に三次元コンピュータグラフィックスでは，透視投影が用いられている．これに対し，人間が描く絵では，複数の視点からの見えを混在させることにより，表現したい対象の特徴を強調した非透視投影が用いられている．本稿では，二次元投影図上の見えを介してユーザが非透視投影図のゆがみを編集することのできる新しい手法を提案する．この手法は，三次元格子点上に定義されたカメラパラメータ場をデータ構造として用いることにより，一つの投影図に複数の視点を混在させることができるようにする．更に，いくつかの基本操作を提供することで，ユーザが二次元投影面を介して，対象シーンを包含するカメラパラメータ場を編集できるようにする．我々の手法を用いることで，三次元シーンの投影図を手描きの絵に合わせるいくつかの設計例を示す．

Guidelines for LoD control in volume visualization

MIYAMURA Hiroko, FUJISHIRO Issei, TAKESHIMA Yuriko, Takeshima, TAKAHASHI Shigeo, SAITO Takafumi

画像電子学会誌 (東京・画像電子学会) 37 ( 4 ) 461 - 468 2008.07

Research paper (scientific journal), Joint Work, Accepted, ISSN 0285-9831

For exploring the inner structures of large scale volume datasets, it is general to use LoD control methods. In order to achieve effective large-scale volume visualization, we propose visualization guidelines to adaptively select appropriate Level of Detail (LoD) control methods according to the predetermined visualization techniques and the setting of parameter values. Our contribution lies in the automatic selection of LoD control methods for visualizing large-scale volume datasets so that even novices can effectively take advantage of the LoD control methods.

Optimization strategies using hybrid MPI+OpenMP parallelization for large-scale data visualization on Earth Simulator

CHEN Li, FUJISHIRO Issei

A Practical Programming Model for the Multi-Core Era (Lecture Notes in Computer Science) (Springer-Verlag) 4935 112-124 2008.07

Research paper (conference, symposium, etc.), Joint Work, Accepted

2次元投影図上の見えの操作に基づいた非透視投影の設計

吉田謙一，高橋成雄，藤代一成，岡田真人

画像電子学会誌 37 ( 4 ) 412 - 418 2008.07

Research paper (scientific journal), Joint Work, Accepted

数万オーダ粒子系のイメージベース可視化

小田川雅人，竹島由里子，藤代一成，菊川豪太，小原拓

第３６回可視化情報シンポジウム講演論文集 (可視化情報学会) 28 ( 1 ) 73 - 74 2008.07

Research paper (conference, symposium, etc.), Joint Work

ハイブリッドボリューム

千葉鉄也，藤代一成，竹島由里子

第３６回可視化情報シンポジウム講演論文集 (可視化情報学会) 28 ( 1 ) 79 - 82 2008.07

Research paper (conference, symposium, etc.), Joint Work

Optimizing parallel performance of streamline visualization for large distributed flow datasets

CHEN Li, FUJISHIRO Issei

Proceedings of IEEE Pacific Visualization Symposium 2008 (IEEE/Eurographics) 87-94 2008.03

Research paper (conference, symposium, etc.), Joint Work, Accepted

Parallel performance has been a challenging topic in streamline visualization for large unstructured flow datasets on parallel distributed-memory computers. It depends strongly on domain partitions. Unsuitable partitions often lead to severe load imbalance and high frequent communications among the domain partitions. To address the problem, we present an approach to flow data partitioning taking account of flow directions and features. Multilevel spectral graph bisection method is employed to reduce communication and synchronization overhead among distributed domains. Edge weights in the corresponding adjacent matrix is defined based on an anisotropic local diffusion operator which assigns strong coupling along flow direction and weak coupling orthogonal to flow. Meanwhile, the distributions of seed points and flow features such as vortex structure are also considered in partitioning so as to obtain good load balance. The
experimental results are given to show the feasibility and
effectiveness of our method.

T-Map: A topological approach to visual exploration of time-varying volume data

FUJISHIRO Issei, OTSUKA Rieko, TAKAHSHI Shigeo, TAKESHIMA Yuriko

High-Performance Computing - 6th International Symposium, ISHPC 2005, Nara, Japan, September 7-9, 2005, First International Workshop on Advanced Low Power Systems, ALPS 2006, Revised Selected Papers (Lecture Notes in Computer Sceince) (Springer-Verlag) 4759 176-190 2008.01

Research paper (conference, symposium, etc.), Joint Work, Accepted

The rapid advance in high performance computing and measurement technologies has recently made it possible to produce a stupendous amount of time-varying volume datasets in a variety of disciplines. However, there exist a few known visual exploration tools that allow us to
investigate the core of their complex dynamics effectively. In this paper, our previous approach to topological volume skeletonization is extended to capture the topological features of large-scale time-varying volume
datasets. A visual exploration tool, termed T-map, is presented, where pixel-oriented information visualization techniques are deployed so that the user can identify partial 4D spatiotemporal domains with characteristic
changes in a topological sense, prior to detailed and comprehensible volume visualization. A case study with datasets from atomic collision research is performed to illustrate the feasibility of the proposed tool.

Locating an optimal light source for volume rendering

NARAOKA Ryota, FUJISHIRO Issei, TAKAHASHI Shigeo, TAKESHIMA Yuriko

Proceedings of Image Elecrtonics and Visual Computing Workshop 2007 (Institute of Image Electronics Engineers of Japan) 2007.11

Research paper (conference, symposium, etc.), Joint Work, Accepted

Locating optimal light sources is an important task for
image synthesis because it significantly influences the
spatial perception of rendered objects. Several methods
have been proposed, which search for the optimal
location of light sources for 3D surfaces, but none has
been done for volumes. This paper presents a novel
method for finding an optimal location of a single parallel
light source for volumetric ray-casting. The method
computes the entropy of brightness distribution of
topologically-significant isosurfaces, and then utilizes a
topologically-enhanced opacity transfer function to assign
a distinct weight to each of the entropy values for the
isosurfaces to evaluate the plausible illumination entropy
for the entire volume. The light with the maximum
entropy value facilitates the observers realizing the
volume features with enriched 3D cues. Empirical
evaluation of the present method with a simple analytic
volume is also included.

GADGET/FV：流れ場の可視化アプリケーション設計支援システム

TAKESHIMA Yuriko, FUJISHIRO Issei

画像電子学会誌 (東京・画像電子学会) 36 ( 5 ) 796 - 806 2007.09

Research paper (scientific journal), Joint Work, Accepted, ISSN 0285-9831

本論文では，可視化目的から有効な可視化技法を特定する目的指向分類であるWehrendマトリックスを拡張した知識ベースを援用することによって，流れ場の可視化アプリケーション設計を支援し，既存のモジュール型可視化環境の利用を促進するシステムGADGET/FVを提案する．GADGET/FVは，ユーザの可視化スキルレベルに応じて支援内容を変化させる適応性だけでなく，作業過程の保存・再利用や，研究メモを可視化結果にリンクさせる機能をもつことによって，ユーザの視覚解析の進捗に合わせた，よりきめの細かい支援を実現している．流体解析の実例を用いて本システムの有効性を示すとともに，Robertsonらが提案する可視化システムの性能を定義する6つの要素にしたがって，本システムの性能を総合的に評価する．

可視化情報

FUJISHIRO Issei

日本機械学会誌 (日本機械学会) 110 ( 1065 ) 595 2007.08

Research paper (scientific journal), Single Work, Accepted

拡散テンソル量の力覚化

小川雄太，藤代一成，竹島由里子

第３５回可視化情報シンポジウム講演論文集 (可視化情報学会) 27 ( 1 ) 47 - 48 2007.07

Research paper (conference, symposium, etc.), Joint Work

情報科学的に美しい可視化アプローチの探求

TAKESHIMA Yuriko, TAKAHASHI Shigeo, FUJISHIRO Issei

情報処理 (東京・情報処理学会) 48 ( 7 ) 766 2007.07

Research paper (scientific journal), Joint Work

協調的可視化環境：(1) 基本コンセプトとアーキテクチャ

藤代一成，竹島由里子

第３５回可視化情報シンポジウム講演論文集 (可視化情報学会) 27 ( 1 ) 39 - 40 2007.07

Research paper (conference, symposium, etc.), Joint Work

協調的可視化環境：(2) 流体融合研究におけるケーススタディ

藤代一成，竹島由里子

第３５回可視化情報シンポジウム講演論文集 (可視化情報学会) 27 ( 1 ) 41 - 42 2007.07

Research paper (conference, symposium, etc.), Joint Work

ボリュームレンダリングおける照明の最適配置

奈良岡亮太，藤代一成，竹島由里子，高橋成雄

第３５回可視化情報シンポジウム講演論文集 (可視化情報学会) 27 ( 1 ) 45 - 46 2007.07

Research paper (conference, symposium, etc.), Joint Work

Optimization strategies using hybrid MPI+OpenMP parallelization for large-scale data visualization on Earth Simulator

Li Chen,FUJISHIRO Issei

Proceedings of International Workshop on OpenMP 2007 Beijing 104 - 115 2007.06

Research paper (international conference proceedings), Joint Work, Accepted

見せない可視化

FUJISHIRO Issei

画像電子学会誌 (東京・画像電子学会) 36 ( 3 ) 193 2007.05

Research paper (scientific journal), Single Work, Accepted, ISSN 0285-9831

協調的可視化の役割 - 応用設計とパラメタ調整のソフトウェア支援 -

FUJISHIRO Issei, TAKESHIMA Yuriko, TAKAHASHI Shigeo

画像電子学会誌 (東京・画像電子学会) 36 ( 2 ) 146-155 2007.03

Research paper (scientific journal), Joint Work, Accepted, ISSN 0285-9831

等値面の罠

FUJISHIRO Issei

画像電子学会誌 (東京・画像電子学会) 35 ( 6 ) 963-964 2006.11

Research paper (scientific journal), Single Work, Accepted, ISSN 0285-9831

ビジュアリゼーション

FUJISHIRO Issei

画像電子学会誌 (東京・画像電子学会) 35 ( 6 ) 706-708 2006.11

Research paper (scientific journal), Single Work, Accepted, ISSN 0285-9831

Collaborative Visualization: Topological approaches to parameter tweaking for informative volume rendering

FUJISHIRO Issei, TAKAHASHI Shigeo, TAKESHIMA Yuriko

Systems Modeling and Simulation: Theory and Applications, Asia Simulation Conference 2006 (Springer-Verlag, Tokyo) 1-5 2006.10

Research paper (conference, symposium, etc.), Joint Work, Accepted

Data crisis frequently arises in solving complex scientific/engineering problems. It has motivated us to develop a collaborative visualization environment which provides the users with the "serendipity" with the aid of effective data-centric parameter tweaking. To this end, we have proposed the concept of volume data mining (VDM), which takes full advantage of knowledge in the field of differential topology to explore the global structure and local features of a target 4D volume. The current VDM tools include critical point histogram; critical/representative isosurface and cross-section extractors; isosurface embedding locator; multi-dimensional transfer function designer with topological attributes; interval volume decomposer; optimal viewpoint locator; and critical timing finder. In this talk, we illustrate the effectiveness of the VDM tools with applications to real datasets from many disciplines.

Collaborative Visualization: Topological approaches to parameter tweaking for informative volume rendering

FUJISHIRO Issei,TAKAHASHI Shigeo,TAKESHIMA Yuriko

Systems Modeling and Simulation 1 - 5 2006.10

Research paper (international conference proceedings), Joint Work, Accepted

協調的可視化：応用設計とパラメタ調整のソフトウェア支援

FUJISHIRO Issei, TAKESHIMA Yuriko

京都大学学術情報メディアセンター全国共同利用版[広報] (京都大学学術情報メディアセンター) 5 ( 2 ) 11-18 2006.10

Research paper (bulletin of university, research institution), Single Work, ISSN 1347-3581

新時代のCGエンジニア向けテキストとその思想

NOMA Tsukasa, FUJISHIRO Issei, SAITO Takafumi

図学研究（日本図学会誌） (日本図学会) 40 ( 3 ) 27-28 2006.09

Research paper (scientific journal), Joint Work

財団法人画像情報教育振興協会（CG―ARTS 協会）では，平成１６年に新しいCG 教育用テキストを発行し，平成１７年秋からこれらのテキストに基づく新しい検定試験の実施を開始した．新しいテキストと検定試験は，エン
ジニア向けとクリエイター向けに分かれているが，本研究会では，編集者を代表して乃万が，エンジニア向けのテキストの概要と考え方を紹介した．

Diffusion-Based Tractography: Visualizing dense white matter connectivity from 3D tensor fields

MURAKI Shigeru, FUJISHIRO Issei, SUZUKI Yasuko, TAKESHIMA Yuriko

Proceedings of Volume Graphics 2006 (IEEE/Eurographics) 119-126., 146 2006.07

Research paper (conference, symposium, etc.), Joint Work, Accepted

In this paper, we present a novel method, called diffusion-based tractography (DBT), for visualizing diffusion tensor magnetic resonance imaging datasets. The DBT method generates 3D textures similar to the line integral convolution (LIC) by smearing 3D random dot textures. In contrast to the LIC method, which only traces a single
direction, the DBT method takes into account both linear and planar diffusion components, and suppresses excessive
blur by an analysis of three decomposed components. We will demonstrate that the DBT method is effective for visualizing dense white matter connectivity from 3D diffusion tensor fields and that it is suitable for hardware acceleration using commodity graphics processors.

GADGET/FV：ビジュアルフローデータマイニングのためのユーザ支援環境

竹島由里子，藤代一成

第３４回可視化情報シンポジウム講演論文集 (可視化情報学会) 26 ( 1 ) 31 - 34 2006.07

Research paper (conference, symposium, etc.), Joint Work

ボリュームデータの位相構造に基づく自動断面生成

MORI Yuki, TAKAHASHI Shigeo, IGARASHI Takeo, TAKESHIMA Yuriko, FUJISHIRO Issei

画像電子学会誌 (東京・画像電子学会) 35 ( 4 ) 252 - 260 2006.07

Research paper (scientific journal), Joint Work, Accepted, ISSN 0285-9831

ボリュームデータの複雑な内部構造を視覚的に解析する手法の一つに断面の表示がある．内部構造を理解するためには，対象の特徴をよくとらえた断面を抽出することが必要である．しかし，既存システムの断面生成機能では，ユーザが経験や知識をもとに試行錯誤を繰り返して断面を指定するため，必ずしも特徴的な断面が得られているとはいえなかった．そこで本稿では，複数の特徴的な断面を自動的に提示する手法を提案する．本提案手法は，ボリュームデータにおける等値面の位相的な振る舞いに着目することで，その特徴をとらえる断面を自動抽出し，その断面をユーザに効果的に提示する．更に，実データに適用することで，提案手法の有効性を示す．

拡散トラクトグラフィ法による脳内神経繊維の可視化

鈴木靖子，村木茂，藤代一成，竹島由里子

第３４回可視化情報シンポジウム講演論文集 (可視化情報学会) 26 ( 1 ) 29 - 30 2006.07

Research paper (conference, symposium, etc.), Joint Work

ボリュームグラフィックス研究の最前線

FUJISHIRO Issei

日本医用画像工学会誌 24 ( 2 ) 82-87 2006.03

Research paper (scientific journal), Single Work, Accepted

ボリュームグラフィックスは，解析的手法，スキャナ＆センサ計測，数値シミュレーション，統計的観測などから得られる3 次元の空間充填型データに関するモデリング，操作，レンダリングを統合的に取り扱う新しい学問分野である．本稿では，その中核的技術であるボリューム可視化にとくに焦点を当てて，ボリュームグラフィックス研究開発の最新動向を紹介する．

位相的ボリューム骨格化アルゴリズムの改良

TAKESHIMA Yuriko, TAKAHASHI Shigeo, FUJISHIRO Issei

情報処理学会論文誌 (東京・情報処理学会) 47 ( 1 ) 250-261 2006.01

Research paper (scientific journal), Joint Work, Accepted, ISSN 0387-5806

位相的ボリューム骨格化は，スカラ値に関する等値面の位相的な遷移を，ボリューム骨格木とよばれるグラフとして抽出する手法である．ボリューム骨格木は，入力スカラ場に潜在する大局的な構造を効果的に表現するが，逆にスカラ場の量子化や高周波ノイズの影響を受けやすく，大局的な構造の抽出に時間を要するケースが頻繁に生じていた．そこで，本論文ではこれらの計算に必要な時間を大幅に短縮するように位相的ボリューム骨格化アルゴリズムを改良する．具体的には，ボリューム骨格木抽出の計算アルゴリズムの改良それ自体に加え，スカラ値補間のための位相的な誤差基準を考慮した適応的四面体分割の基本アイデアに基づいて改良を行う．シミュレーションなどによるボリュームデータの解析例を通じて，本手法が大幅に計算時間を短縮できることを示し，さらに，得られたボリューム骨格木を用いて大規模なボリュームデータも効果的に可視化できることを示す．

Hierarchical Causality Explorer: Making complemental use of 3D/2D visualizations

AZUMA Shizuka, FUJISHIRO Issei, HORII Hideoyuki

Visualization and Data Analysis 2006, Proceedings of SPIE-IS&T Electronic Imaging (SPIE) 6060 ( 60600H ) 2006.01

Research paper (conference, symposium, etc.), Joint Work, Accepted

Hierarchical causality relationships reside ubiquitously in the reality. Since the relationships take intricate forms with two kinds of links – hierarchical abstraction and causal association, there exists no single visualization style that allows the user to comprehend them effectively. This paper introduces a novel information visualization framework which can change existing 3D and 2D display styles interactively according to the user’s visual analysis demands. The two visualization styles play a complementary role, and the change in the style relies on morphing so as to maintain the user’s cognitive map. Based on this framework, we have developed a general-purpose prototype system, which provides the user with an enriched set of functions not only for supporting fundamental information seeking, but bridging analytic gaps to accomplishing high-level analytic tasks such as knowledge discovery and decision making. The effectiveness of the system is illustrated with an application to the analysis of a nuclear-hazard cover-up problem.

Development of pants slopers with automatic drafting functions and human body measurement for use in apparel CAD education

YAMAMOTO Takami,DOI Misuzu,FUJISHIRO Issei

Proceedings of CAD/Graphics 2005 193 - 198 2005.12

Research paper (international conference proceedings), Joint Work, Accepted

A feature-driven approach to locating optimal viewpoints for volume visualization

TAKAHASHI Shigeo,FUJISHIRO Issei,TAKESHIMA Yuriko,NISHITA Tomoyuki

Proceedings of IEEE Visualization 2005 495 - 502 2005.10

Research paper (international conference proceedings), Joint Work, Accepted

位相属性を用いた多次元伝達関数設計

竹島由里子，高橋成雄，藤代一成

情報処理学会論文誌 46 ( 10 ) 2566 - 2575 2005.10

Research paper (scientific journal), Joint Work, Accepted

対話型再進化計算に基づくアパレルデザイン支援におけるブラウジング手法

土井美鈴，山本高美，藤代一成

情報科学技術レターズ 4 173 - 176 2005.09

Research paper (scientific journal), Joint Work, Accepted

Automatic cross-sectioning based on topological volume skeletonization

MORI Yuki,TAKAHASHI Shigeo,TAKESHIMA Yuriko,IGARASHI Takeo,FUJISHIRO Issei

Smart Graphics: 5th Inter- national Symposium, SG 2005, Frauenw¨orth Cloister 3638 175 - 184 2005.08

Research paper (international conference proceedings), Joint Work, Accepted

Access to Document (DOI)

Emphasizing isosurface embeddings in direct volume rendering

TAKAHASHI Shigeo,TAKESHIMA Yuriko,FUJISHIRO Issei, NIELSON Gregory M.

Scientiﬁc Visualization 185 - 206 2005.08

Research paper (international conference proceedings), Joint Work, Accepted

レーザ核融合における爆縮現象の位相解析と可視化

竹島由里子，高橋成雄，藤代一成，坂上仁志

第３３回可視化情報シンポジウム講演論文集 (可視化情報学会) 25 ( 1 ) 139 - 142 2005.07

Research paper (conference, symposium, etc.), Joint Work

Introducing topological attributes for objective-based visualization of simulated datasets

TAKESHIMA Yuriko,TAKAHASHI Shigeo,FUJISHIRO Issei,Gregory M. Nielson

Proceedings of International Workshop on Volume Graphics 2005 137 - 145 2005.06

Research paper (international conference proceedings), Joint Work, Accepted

Point-based uniﬁcation of complex data visualization

FUJISHIRO Issei,TAKESHIMA Yuriko,ONO Kaori,KOSHIZUKA Seiichi

Proceedings of NICOGRAPH International 2005 147 - 148 2005.05

Research paper (international conference proceedings), Joint Work, Accepted

パンツスローパ自動作図機能の開発とその授業実践

山本高美，土井美鈴，藤代一成

お茶の水女子大学論叢 7 473 - 481 2005.03

Research paper (scientific journal), Joint Work, Accepted

Extraction and LOD control of colored interval volume

NAKAMURA Hiroko,TAKESHIMA Yuriko,FUJISHIRO Issei,SAITO Takafumi

Proceedings of Visualization and Data Analysis 2005 5669 95 - 102 2005.01

Research paper (international conference proceedings), Joint Work, Accepted

Interval Volume Decomposer: A topological approach to volume traversal

TAKAHASHI Shigeo,FUJISHIRO Issei,TAKESHIMA Yuriko

Proceedings of Visualization and Data Analysis 2005 5669 103 - 114 2005.01

Research paper (international conference proceedings), Joint Work, Accepted

Parallel visualization of large-scale unstructured geo- physical data for the Earth Simulator

Li Chen,FUJISHIRO Issei,NAKAJIMA Kengo

Pure and Applied Geophysics (Springer-Verlag) 161 ( 11 ) 2245 - 2263 2004.12

Research paper (scientific journal), Joint Work, Accepted

Volumetric computing graphics cluster — A successful result of cooperative research between private companies and national institutions —

OGATA Masato,KAJIHARA Kagenori,KURITA Takio,FUJISHIRO Issei

Proceedings of Tenth International Conference on Virtual Systems and Multimedia 220 - 224 2004.11

Research paper (international conference proceedings), Joint Work, Accepted

comp-i: A system for visual exploration and editing of MIDI datasets

MIYAZAKI Reiko,FUJISHIRO Issei,HIRAGA Rumi

Proceedings of 2004 International Computer Music Conference 157 - 164 2004.11

Research paper (international conference proceedings), Joint Work, Accepted

原子力発電所トラブル隠し問題の解析に向けた階層的因果関係の対話的可視化

我妻静香，藤代一成，堀井秀之

社会技術研究論文集 2 406 - 413 2004.10

Research paper (conference, symposium, etc.), Joint Work, Accepted

アパレルCAD教育のための自動作図機能に基づいたブラウス用ディテールパターンのアーカイブ

山本高美，土井美鈴，藤代一成

画像電子学会誌 33 ( 5 ) 696 - 704 2004.09

Research paper (scientific journal), Joint Work, Accepted

Detail-preserving regular resampling for parallel volume rendering large unstructured data on Earth Simulator

CHEN Li,FUJISHIRO Issei,NAKAJIMA Kengo

Proceedings of IASTED Interna- tional Conference on Computer Graphics and Imaging 2004 242 - 247 2004.08

Research paper (international conference proceedings), Joint Work, Accepted

位相的特徴解析に基づく数値標高モデルの詳細度制御

中村浩子，高橋成雄，藤代一成

可視化情報学会論文集 24 ( 7 ) 23 - 30 2004.07

Research paper (scientific journal), Joint Work, Accepted

Automatic enhancement of human character animation based on psychophysical measures

FUJISIMA Tomoko,FUJISHIRO Issei

Proceedings of NICOGRAPH International 2004 12 - 15 2004.05

Research paper (international conference proceedings), Joint Work, Accepted

Topological volume skeletonization using adaptive tetrahedralization

TAKAHASHI Shigeo,NIELSON Gregory M.,TAKESHIMA Yuriko,FUJISHIRO Issei

Proceedings of Geometric Modeling and Processing 2004 (IEEE Computer Society Press) 227 - 236 2004.04

Research paper (international conference proceedings), Joint Work, Accepted

可視化パラメタを考慮した四面体ボリュームの適応的詳細度制御

中村浩子，藤代一成，竹島由里子

画像電子学会誌 33 ( 2 ) 171 - 179 2004.03

Research paper (scientific journal), Joint Work, Accepted

デジタルスコアによる楽曲学習支援インタフェース

渡辺ふみ子，藤代一成，平賀瑠美

情報処理学会論文誌 45 ( 3 ) 710 - 718 2004.03

Research paper (scientific journal), Joint Work, Accepted

comp-i：MIDI データの視覚探索システム

宮崎麗子，藤代一成，平賀瑠美

情報処理学会論文誌 45 ( 3 ) 739 - 742 2004.03

Research paper (scientific journal), Joint Work, Accepted

Topological volume skeletonization and its application to transfer function design

TAKAHASHI Shigeo,TAKESHIMA Yuriko,FUJISHIRO Issei

Graphical Models 66 ( 1 ) 24 - 49 2004.01

Research paper (scientific journal), Joint Work, Accepted

社会問題の解決に資する事実の明示化手法の構築

山口健太郎，船戸康徳，藤代一成，堀井秀之

社会技術研究論文集 1 9 - 15 2003.10

Research paper (conference, symposium, etc.), Joint Work, Accepted

BRASS: Visualizing scores for assisting music learning

WATANABE Fumiko,HIRAGA Rumi,FUJISHIRO Issei

Proceedings of 2003 International Computer Music Conference 107 - 114 2003.09

Research paper (international conference proceedings), Joint Work, Accepted

ヒトの視覚特性を考慮した心象風景レンダリング

河島修生，藤代一成

芸術科学会論文誌 2 ( 3 ) 101 - 104 2003.09

Research paper (scientific journal), Joint Work, Accepted

社会問題の解決に資する問題の構造化手法の確立に関する基礎的研究

山口健太郎，船戸康徳，藤代一成，堀井秀之

第３１回可視化情報シンポジウム講演論文集 (可視化情報学会) 23 ( 1 ) 395 - 398 2003.07

Research paper (conference, symposium, etc.), Joint Work

位相解析に基づくボリュームビジュアリゼーションの高度化

徳永百重，竹島由里子，高橋成雄，藤代一成

画像電子学会誌, 32 ( 4 ) 418 - 427 2003.07

Research paper (scientific journal), Joint Work, Accepted

時系列ボリュームの位相骨格抽出とその応用

濱岡史，藤代一成，高橋成雄，竹島由里子

第３１回可視化情報シンポジウム講演論文集 (可視化情報学会) 23 ( 1 ) 391 - 394 2003.07

Research paper (conference, symposium, etc.), Joint Work

Applying volume-topology-based control of visualization parameters to ﬂuid data,

TAKESHIMA Yuriko,TERASAKA H.,SHIMIZU S.,TAKAHASHI Shigeo,FUJISHIRO Issei

CD-ROM Proceedings of Fourth Paciﬁc Symposium on Flow Visualization and Image Processing 2003.06

Research paper (international conference proceedings), Joint Work, Accepted

Optimizing parallel performance of unstructured volume rendering for the Earth Simulator

Li Chen,FUJISHIRO Issei,NAKAJIMA Kengo

Parallel Computing 29 ( 3 ) 355 - 371 2003.03

Research paper (scientific journal), Joint Work, Accepted

Topologically-accentuated volume rendering

FUJISHIRO Issei,TAKESHIMA Yuriko,TAKAHASHI Shigeo,YAMAGUCHI Yumi

Data Visualization 95 - 108 2003

Research paper (international conference proceedings), Joint Work, Accepted

Performance visualization — A new challenge to music through visualization

HIRAGA Rumi,MIYAZAKI Reiko,FUJISHIRO Issei

Proceedings of Tenth ACM International Conference on Multimedia 239 - 242 2002.12

Research paper (international conference proceedings), Joint Work, Accepted

Parallel performance optimization of large-scale unstructured data visualization for the Earth Simulator

Li Chen,FUJISHIRO Issei,NAKAJIMA Kengo

Parallel Visualization and Graphics 2002 Eurographics Workshop Proceedings 113 - 140 2002.09

Research paper (international conference proceedings), Joint Work, Accepted

Modeling surperspective projection of landscapes for geographical guide-map generation

TAKAHASHI Shigeo,OHTA Naoya,NAKAMURA Hiroko,TAKESHIMA Yuriko,FUJISHIRO Issei

Computer Graphics Forum(Proceedings of Eurographics 2002) 21 ( 3 ) 259 - 268 2002.09

Research paper (scientific journal), Joint Work, Accepted

A visualization environment for multiple daytime stock predictions

ICHIKAWA Yoshihiko,TSUNAWAKI Tomoko,FUJISHIRO Issei,Hiwon Yoon

Proceedings of Second IASTED International Conference Visualization 693 - 698 2002.09

Research paper (international conference proceedings), Joint Work, Accepted

T-Project：位相解析に基づくボリュームデータマイニング

藤代一成，高橋成雄，竹島由里子，大塚理恵子，徳永百重，安藤祥子

第３０回可視化情報シンポジウム講演論文集 (可視化情報学会) 22 ( 1 ) 101 - 104 2002.07

Research paper (conference, symposium, etc.), Joint Work

T-map：位相的特徴解析に基づく時系列ボリュームデータマイニング手法

大塚理恵子，藤代一成，高橋成雄，竹島由里子

画像電子学会誌 31 ( 4 ) 504 - 513 2002.07

Research paper (scientific journal), Joint Work, Accepted

ボリュームデータマイニングのための伝達関数の合成

山口裕美，藤代一成，竹島由里子，高橋成雄，伊藤貴之

映像情報メディア学会誌 56 ( 6 ) 79 - 84 2002.06

Research paper (scientific journal), Joint Work, Accepted

Coherence-sensitive solid ﬁtting

FUJISHIRO Issei,TAKESHIMA Yuriko

Computers & Graphics 26 ( 3 ) 417 - 427 2002.06

Research paper (scientific journal), Joint Work, Accepted

Volume modeling of gas dispersion systems — Representing visual deliciousness of chiﬀon cakes —

ABE Yuko,FUJISHIRO Issei

Proceedings of NICOGRAPH International 2002 47 - 50 2002.05

Research paper (international conference proceedings), Joint Work, Accepted

A volume graphics approach to weathering of stones with moss eﬀects

MIYAKE Yoko,FUJISHIRO Issei

Proceedings of NICOGRAPH International 2002 51 - 54 2002.05

Research paper (international conference proceedings), Joint Work, Accepted

異なる力覚呈示装置による形状知覚の比較

韓恵栄，山下樹里，藤代一成

Interaction 2002 79 - 80 2002.03

Research paper (conference, symposium, etc.), Joint Work, Accepted

Volume graphics modeling of ice thawing

FUJISHIRO Issei,AOKI Etsuko

Volume Graphics 2001 69 - 80 2001.12

Research paper (international conference proceedings), Joint Work, Accepted

tutti:音楽データのブラウジング・編集のための3次元インタラクティブインタフェース

渡辺綾子，藤代一成

インタラクティブシステムとソフトウェアIX（レクチャーノート/ソフトウェア学27） (近代科学社) 33 - 38 2001.12

Research paper (conference, symposium, etc.), Joint Work, Accepted

雲のモデリング／アニメーション制作支援システム

黒宮寧，藤代一成

第17回NICOGRAPH 論文コンテスト論文集 (芸術科学会) 45 - 50 2001.11

Research paper (conference, symposium, etc.), Joint Work, Accepted

Coherence-sensitive solid ﬁtting

FUJISHIRO Issei,TAKESHIMA Yuriko

Proceedings of Seventh International Conference on Computer Aided Design and Computer Graphics 1 379 - 386 2001.09

Research paper (international conference proceedings), Joint Work, Accepted

重要度マップと流線照明モデルに基づく選択的3次元LICボリュームレンダリング

鈴木靖子，藤代一成，陳莉

画像電子学会誌 30 ( 4 ) 379 - 387 2001.07

Research paper (scientific journal), Joint Work, Accepted

ボリュームの骨格化と肉付け

藤代一成，高橋成雄，竹島由里子，大塚理恵子

第２９回可視化情報シンポジウム講演論文集 (可視化情報学会) 21 ( 1 ) 145 - 146 2001.07

Research paper (conference, symposium, etc.), Joint Work

色属性をもつ区間型ボリューム抽出および詳細度制御

中村浩子，竹島由里子，藤代一成

第２９回可視化情報シンポジウム講演論文集 (可視化情報学会) 21 ( 1 ) 147 - 150 2001.07

Research paper (conference, symposium, etc.), Joint Work

形状/色分布特徴を考慮した区間型ボリュームの半自動詳細度制御

中村浩子，竹島由里子，藤代一成，奥田洋司

情報処理学会論文誌 42 ( 5 ) 1115 - 1123 2001.05

Research paper (scientific journal), Joint Work, Accepted

デイトレーディング用の株取引可視化システム

山下陽子，市川哲彦，藤代一成，尹熙元

電子情報通信学会第 12 回データ工学ワークショップ (DEWS2001) 2001.03

Research paper (conference, symposium, etc.), Joint Work, Accepted

PCベースの記録可能な複合現実感環境の実現を目指して

瀬川真智子，藤代一成

インタラクティブシステムとソフトウェアVIII（レクチャーノート/ソフトウェア学24） (近代科学社) 241 - 242 2000.12

Research paper (conference, symposium, etc.), Joint Work, Accepted

Feather:大量パターン複製のためのストロークベース変形ツール

原田あす香，藤代一成

第16 回 NICOGRAPH/MULTIMEDIA 論文コンテスト論文集 105 - 110 2000.11

Research paper (conference, symposium, etc.), Joint Work, Accepted

Parallel visualization utilities for solid earth simulation platform GeoFEM

FUJISHIRO Issei,TAKESHIMA Yuriko,NAKAMURA Hiroko,SUZUKI Yasuko

CD-ROM Proceedings of Fourth Inter- national Conference on Supercomputing in Nuclear Applications(SNA2000) 2000.09

Research paper (international conference proceedings), Joint Work, Accepted

時系列ボリュームデータマイニングのための位相解析アプローチ

竹島由里子，藤代一成，山口裕美，高橋成雄

第２８回可視化情報シンポジウム講演論文集 (可視化情報学会) 20 ( 1 ) 163 - 166 2000.07

Research paper (conference, symposium, etc.), Joint Work

3方向の平行粗断像列を用いた高品質ボリューム補間

立野玲子,山口裕美,藤代一成,東多恵子,桜庭均

画像電子学会誌 29 ( 4 ) 292 - 301 2000.07

Research paper (scientific journal), Joint Work, Accepted

色えんぴつ画の周辺技法のボリュームモデリング

高木佐恵子，藤代一成，中嶋正之

情報処理学会論文誌 41 ( 3 ) 616 - 624 2000.03

Research paper (scientific journal), Joint Work, Accepted

A morphological approach to volume synthesis of weathered stones

OZAWA Nao,FUJISHIRO Issei

Volume Graphics 367 - 378 2000.03

Research paper (international conference proceedings), Joint Work, Accepted

GADGET/IV：情報可視化の半自動設計支援環境

古畑理香，藤代一成，市川哲彦，竹島由里子

電子情報通信学会第 11 回データ工学ワークショップ (DEWS2000) 2000.03

Research paper (conference, symposium, etc.), Joint Work, Accepted

Fast LIC image generation based on signiﬁcance map

Li Chen,FUJISHIRO Issei,Qunsheng Peng

High Performance Computing — Third International Symposium ( 1940 ) 537 - 546 2000

Research paper (international conference proceedings), Joint Work, Accepted

Volumetric modeling of colored pencil drawing

TAKAGI Saeko,FUJISHIRO Issei,NAKAJIMA Masayuki

Proceedings of Paciﬁc Graphics ’99 (Seventh Paciﬁc Conference on Computer Graphics and Applications) (IEEE Computer Society Press) 250 - 258 1999.10

Research paper (international conference proceedings), Joint Work, Accepted

ビルボードを用いた大規模球群可視化アニメーションの高速化

北山暁子,藤代一成,平野恒夫，奥田洋司

Computer Visualization Symposium ’99論文集, (日経サイエンス社) 61 - 64 1999.06

Research paper (conference, symposium, etc.), Joint Work, Accepted

ボリュームモデリングによる色えんぴつ画の表現

高木佐恵子,藤代一成,中嶋正之

Computer Visualization Symposium ’99論文集 (日経サイエンス社) 17 - 20 1999.06

Research paper (conference, symposium, etc.), Joint Work, Accepted

学内LAN データの視覚化とナビゲーションによる利用者支援：情報可視化支援システム構築に向けて

稲本実保子，市川哲彦，藤代一成

電子情報通信学会第10回データ工学ワークショップ (DEWS’99) 1999.03

Research paper (conference, symposium, etc.), Joint Work, Accepted

色えんぴつ画のボリュームモデリング

高木佐恵子，藤代一成，中嶋正之

情報処理学会論文誌 40 ( 3 ) 1177 - 1187 1999.03

Research paper (scientific journal), Joint Work, Accepted

共感覚を用いた擬似ハプタイゼーション

杉本美香，藤代一成

情報処理学会インタラクション’99 論文集 193 - 200 1999.03

Research paper (conference, symposium, etc.), Joint Work, Accepted

仮想社会におけるユーザ行動の検索と再現

倉持陽子，藤代一成，内藤剛人

インタラクティブシステムとソフトウェア VI（レクチャーノート/ソフトウェア学 21） (近代科学社) 67 - 72 1998.12

Research paper (conference, symposium, etc.), Joint Work, Accepted

タイムクリティカルレンダリング：人間行動モデルに基づく適応的テクスチャマッピング

田中利果，藤代一成

日本バーチャルリアリティ学会論文誌 3 ( 3 ) 159 - 166 1998.09

Research paper (scientific journal), Joint Work, Accepted

低から中程度のエネルギーによる陽子・水素原子衝突の可視化

渡部亜矢子，佐藤浩史，藤代一成，市川哲彦

可視化情報（可視化情報学会誌） 18 ( 68 ) 23 - 28 1998.01

Research paper (scientific journal), Joint Work, Accepted

階層的空間索引構造を用いた区間型ボリュームの高速抽出

藤代一成，竹島由里子，前田裕治

情報処理学会論文誌 38 ( 8 ) 1593 - 1602 1997.08

Research paper (scientific journal), Joint Work, Accepted

Visualizing liquid-gas two-phase ﬂow

SHIRAI Izuru,OHASHI Hirotada,AKIYAMA Minoru,FUJISHIRO Issei,EHIRO Masumi,MORI Michitsugu

Proceedings of Eurographics Workshop on Implicit Surfaces ’96 153 - 162 1996.10

Research paper (international conference proceedings), Joint Work, Accepted

Three-dimensional brain visualization for metachromatic leukodystrophy

TACHINO M.Reiko,MAEDA Yuji,FUJISHIRO Issei,ITOH Koji,SATAKE Akira,AOKI Shigeki,YAMADA Hideo,SUZUKI Yoshiyuki,SAKURABA Hitoshi

Brain & Development(Oﬃcial Journal of the Japanese Society of Child Neurology) 18 ( 5 ) 394 - 399 1996.09

Research paper (scientific journal), Joint Work, Accepted

C2IMA: A classiﬁcation and case based instruction system for visualization network design

NAKAMURA Kyoko,FUJISHIRO Issei,ICHIKAWA Yoshihiko

Proceedings of First International Conference on Virtual Systems and Multimedia(VSMM)’95 118 - 123 1995.09

Research paper (international conference proceedings), Joint Work, Accepted

L-reps: 2次元ディスプレイ上で3次元ピンポイントを可能にする2次元指向幾何変換モデル

高山毅，藤代一成，蔡東生，池辺八洲彦

図学研究（日本図学会論文誌） ( 67 ) 3 - 15 1995.03

Research paper (scientific journal), Joint Work, Accepted

L-Reps: A drafting- oriented approach to unambiguous and precise design of 3D mechanical products

TAKAYAMA Tsuyoshi,FUJISHIRO Issei,IKEBE Yasuhiko,Dong-Sheng Cai

Proceedings of Sixth International Conference on Engineering Computer Graphics and Descriptive Geometry 177 - 181 1994.08

Research paper (international conference proceedings), Joint Work, Accepted

非負実数階第1種ベッセル関数の零点計算アルゴリズム

菊池靖，浅井信吉，宮崎佳典，蔡東生，藤代一成，池辺八洲彦

日本応用数理学会論文誌 3 ( 4 ) 147 - 159 1993.12

Research paper (scientific journal), Joint Work, Accepted

The eigenvalue problem for inﬁnite compact complex symmetric matrices with appli- cation to the numerical computation of complex zeros of J0(z)−ıJ1(z) and of Bessel functions Jm(z) of any real order m

IKEBE Yasuhiko,KIKUCHI Yasushi,:FUJISHIRO Issei, ASAI Nobuyoshi,TAKANASHI Kokichi,HARADA Minoru

Linear Algebra and its Applications 194 35 - 70 1993

Research paper (scientific journal), Joint Work, Accepted

GIDBS: A database system for hierarchically represented gray-scale images

Xiaoyang Mao,FUJISHIRO Issei,KUNII Tosiyasu L.,SHIMIZU Akira

Three-Dimensional Modeling with Geoscientiﬁc Information Systems 259 - 281 1992

Research paper (international conference proceedings), Joint Work, Accepted

個別化されたファジィデータ管理のためのグラフスキーマ設計

藤代一成，白井靖人，池辺八洲彦，國井利泰

日本ファジィ学会論文誌 3 ( 1 ) 86 - 97 1991.01

Research paper (scientific journal), Joint Work, Accepted

Computing zeros and orders of Bessel functions

IKEBE Yasuhiko,KIKUCHI Yasushi,FUJISHIRO Issei

Journal of Computational and Applied Mathematics 38 169 - 184 1991

Research paper (scientific journal), Joint Work, Accepted

A translucent display algorithm for G-octree represented gray-scale images

Xiaoyang Mao,FUJISHIRO Issei,KUNII Tosiyasu L.

Journal of Visualization and Computer Animation 1 ( 1 ) 22 - 25 1990.08

Research paper (scientific journal), Joint Work, Accepted

Graph-based formulation of fuzzy data

SHIRAI Yasuto,FUJISHIRO Issei,KUNII Tosiyasu L.

Progress in Fuzzy Sets and Systems 147 - 160 1990

Research paper (international conference proceedings), Joint Work, Accepted

The divided diﬀerence table from a matrix viewpoint

IKEBE Yasuhiko,FUJISHIRO Issei,ASAYAMA Yusuke

Journal of Information Processing 12 ( 4 ) 404 - 405 1989.05

Research paper (scientific journal), Joint Work, Accepted

Graph-based representation of fuzzy data

SHIRAI Yasuto,FUJISHIRO Issei,KUNII Tosiyasu L.

Proceedings of Second Joint IFSA-EC EURO-WG Workshop on Progress in Fuzzy Sets in Europe 66 - 69 1989.04

Research paper (international conference proceedings), Joint Work, Accepted

Extending external views on a link-oriented data model

FUJISHIRO Issei,SHIRAI Yasuto,KUNII Hideko S.,KUNII Tosiyasu L.

Proceedings of IEEE Eleventh Annual International Computer Software and Applications Conference(COMPSAC) 87 (IEEE Computer Society) 397 - 403 1987.10

Research paper (international conference proceedings), Joint Work, Accepted

Reconstruction and cross-section generation of hierarchically represented 3D gray-scale digital images

Xiaoyang Mao,KUNII Tosiyasu L.,FUJISHIRO Issei,NOMA Tsukasa

Computer Graphics 1987 461 - 481 1987.06

Research paper (international conference proceedings), Joint Work, Accepted

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