Details of a Researcher - Fujishiro, Issei

Papers - Fujishiro, Issei

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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.

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