Details of a Researcher - Fujishiro, Issei

Papers - Fujishiro, Issei

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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.

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