Papers - Fujishiro, Issei

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

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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

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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

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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

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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

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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

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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

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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

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© 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

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© 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

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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

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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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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

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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