Performance information

• Two-Stage Optimization for Fitting Parameters of Measured Isotropic Spectral BRDFs
  Mahiro Sato; Kei Iwasaki
  2024 Nicograph International (NicoInt), First page：36, Last page：40, Jun. 2024, [Reviewed], [Last, Corresponding]
  IEEE, International conference proceedings
  DOI：https://doi.org/10.1109/nicoint62634.2024.00016
  DOI ID：10.1109/nicoint62634.2024.00016, 共同研究・競争的資金等ID：45500430;45251333;44577530
• Separation of Reflection Components for Measured Spectral BRDFs.　　　　　　　　　　　　　　　
  Masahiro Hikichi; Kei Iwasaki
  Graphics Interface, First page：20:1, Last page：20:9, May 2024, [Reviewed], [Last, Corresponding]
  International conference proceedings
  DOI：https://doi.org/10.1145/3670947.3670953
  DOI ID：10.1145/3670947.3670953, DBLP ID：conf/graphicsinterface/HikichiI24, 共同研究・競争的資金等ID：45500430;45251333;44577530
• A Non-parametric Factor Representation and Editing for Measured Anisotropic Spectral BRDFs.　　　　　　　　　　　　　　　
  Kei Iwasaki; Yoshinori Dobashi
  Graphics Interface, First page：18:1, Last page：18:10, May 2024, [Reviewed], [Lead, Corresponding]
  International conference proceedings
  DOI：https://doi.org/10.1145/3670947.3670951
  DOI ID：10.1145/3670947.3670951, DBLP ID：conf/graphicsinterface/IwasakiD24, 共同研究・競争的資金等ID：45251333;44577530;26367727
• Efficient Visualization of Light Pollution for the Night Sky
  Yoshinori Dobashi; Naoto Ishikawa; Kei Iwasaki
  ACM Transactions on Graphics, Volume：42, Number：6, First page：1, Last page：11, Dec. 2023, [Reviewed]
  Artificial light sources make our daily life convenient, but cause a severe problem called light pollution. We propose a novel system for efficient visualization of light pollution in the night sky. Numerous methods have been proposed for rendering the sky, but most of these focus on rendering of the daytime or the sunset sky where the sun is the only, or dominant light source. For the visualization of the light pollution, however, we must consider many city light sources on the ground, resulting in excessive computational cost. We address this problem by precomputing a set of intensity distributions for the sky illuminated by city light at various locations and with different atmospheric conditions. We apply a principal component analysis and fast Fourier transform to the precomputed distributions, allowing us to efficiently visualize the extent of the light pollution. Using this method, we can achieve one to two orders of magnitudes faster computation compared to a naive approach that simply accumulates the scattered intensity for each viewing ray. Furthermore, the fast computation allows us to interactively solve the inverse problem that determines the city light intensity needed to reduce light pollution. Our system provides the user with both a forward and inverse investigation tool for the study and minimization of light pollution.
  Association for Computing Machinery (ACM), English, Scientific journal
  DOI：https://doi.org/10.1145/3618337
  DOI ID：10.1145/3618337, ISSN：0730-0301, eISSN：1557-7368
• Optical Parameter Estimation for Hair and Fur using Differentiable Rendering.　　　　　　　　　　　　　　　
  Yusei Shibaike; Kei Iwasaki
  SIGGRAPH Asia Technical Communications, First page：3, Last page：4, Dec. 2022, [Reviewed], [Last, Corresponding]
  International conference proceedings
  DOI：https://doi.org/10.1145/3550340.3564221
  DOI ID：10.1145/3550340.3564221, DBLP ID：conf/siggrapha/ShibaikeI22
• Adaptive Irradiance Sampling for Many-Light Rendering of Subsurface Scattering.　　　　　　　　　　　　　　　
  Kosuke Nabata; Kei Iwasaki
  IEEE Transactions on Visualization and Computer Graphics, Volume：28, Number：10, First page：3324, Last page：3335, Oct. 2022, [Reviewed], [Last, Corresponding]
  Scientific journal
  DOI：https://doi.org/10.1109/TVCG.2021.3066640
  DOI ID：10.1109/TVCG.2021.3066640, DBLP ID：journals/tvcg/NabataI22
• Rendering of Scratched Transparent Materials using Precomputed SV-BSDFs.　　　　　　　　　　　　　　　
  Shintaro Fuji; Syuhei Sato; Kei Iwasaki; Yoshinori Dobashi; Shangce Gao; Zheng Tang
  SIGGRAPH Posters, First page：42, Last page：2, Aug. 2022, [Reviewed]
  International conference proceedings
  DOI：https://doi.org/10.1145/3532719.3543207
  DOI ID：10.1145/3532719.3543207, DBLP ID：conf/siggraph/FujiSIDGT22
• Binary space partitioning visibility tree for polygonal and environment light rendering.　　　　　　　　　　　　　　　
  Hiroki Okuno; Kei Iwasaki
  The Visual Computer, Volume：37, Number：9-11, First page：2499, Last page：2511, Jun. 2021, [Reviewed], [Last, Corresponding]
  English, Scientific journal
  DOI：https://doi.org/10.1007/s00371-021-02181-8
  DOI ID：10.1007/s00371-021-02181-8, DBLP ID：journals/vc/OkunoI21
• Temporal and spatial anti-aliasing for rendering reflections on water waves.　　　　　　　　　　　　　　　
  Namo Podee; Nelson Max; Kei Iwasaki; Yoshinori Dobashi
  Comput. Vis. Media, Volume：7, Number：2, First page：201, Last page：215, Mar. 2021, [Reviewed]
  English, Scientific journal
  DOI：https://doi.org/10.1007/s41095-021-0204-1
  DOI ID：10.1007/s41095-021-0204-1, DBLP ID：journals/cvm/PodeeMID21, 共同研究・競争的資金等ID：14229597;26367727
• Two-stage Resampling for Bidirectional Path Tracing with Multiple Light Sub-paths.　　　　　　　　　　　　　　　
  Kosuke Nabata; Kei Iwasaki; Yoshinori Dobashi
  Computer Graphics Forum, Volume：39, Number：7, First page：219, Last page：230, Nov. 2020, [Reviewed], [Corresponding]
  English, Scientific journal
  DOI：https://doi.org/10.1111/cgf.14139
  DOI ID：10.1111/cgf.14139, DBLP ID：journals/cgf/NabataID20, 共同研究・競争的資金等ID：14229597;26367727
• Resampling-aware Weighting Functions for Bidirectional Path Tracing Using Multiple Light Sub-Paths　　　　　　　　　　　　　　　
  Kosuke Nabata; Kei Iwasaki; Yoshinori Dobashi
  ACM Transactions on Graphics, Volume：39, Number：2, First page：15:1, Last page：15:11, Mar. 2020, [Reviewed], [Corresponding]
  English, Scientific journal
  共同研究・競争的資金等ID：14229597;26367727
• Binary Space Partitioning Visibility Tree for Polygonal Light Rendering.　　　　　　　　　　　　　　　
  Hiroki Okuno; Kei Iwasaki
  SIGGRAPH Asia 2019 Technical Briefs, SA 2019, Brisbane, QLD, Australia, November 17-20, 2019, First page：79, Last page：82, Nov. 2019, [Reviewed], [Last, Corresponding]
  ACM, English, International conference proceedings
  DOI：https://doi.org/10.1145/3355088.3365153
  DOI ID：10.1145/3355088.3365153, DBLP ID：conf/siggrapha/OkunoI19
• Temporal and spatial anti-aliasing for rendering reflection on a water surface.　　　　　　　　　　　　　　　
  Namo Podee; Nelson Max; Kei Iwasaki; Yoshinori Dobashi
  Special Interest Group on Computer Graphics and Interactive Techniques Conference, SIGGRAPH 2019, Posters, Los Angeles, California, USA, July 28 - August 1, 2019., First page：50:1-50:2, Jul. 2019, [Reviewed]
  ACM, English, International conference proceedings
  DOI：https://doi.org/10.1145/3306214.3338599
  DOI ID：10.1145/3306214.3338599, DBLP ID：conf/siggraph/PodeeMID19
• A method for estimating the errors in many-light rendering with supersampling.
  Hirokazu Sakai; Kosuke Nabata; Shinya Yasuaki; Kei Iwasaki
  Computational Visual Media, Volume：5, Number：2, First page：151, Last page：160, Apr. 2019, [Reviewed], [Last, Corresponding]
  English, Scientific journal
  DBLP ID：journals/cvm/SakaiNYI19
• Sawtooth cycle revisited　　　　　　　　　　　　　　　
  Junki Tsuruga; Kei Iwasaki
  Computer Animation and Virtual Worlds, Volume：29, Number：3-4, First page：4.59‐4.60, May 2018, [Reviewed], [Last, Corresponding]
  Solving the pressure Poisson equation dominates a large portion of computational time for incompressible fluid flow simulations. To solve the pressure Poisson equation efficiently, geometric multigrid methods are used directly or used as the preconditioner for the conjugate gradient (CG) method. Conventionally, the V-cycle multigrid method is widely employed, and little attention has been paid to other cycles. In this paper, we introduce the sawtooth cycle multigrid method and its simple extension called N-cycle, which provides better convergence in equal time comparison with the V-cycle as a direct solver of the pressure Poisson equation. We also apply the N-cycle to the preconditioner of the CG method and show that the N-cycle multigrid CG method can provide better convergence than the V-cycle multigrid CG method.
  John Wiley and Sons Ltd, English, Scientific journal
  DOI：https://doi.org/10.1002/cav.1836
  DOI ID：10.1002/cav.1836, ISSN：1546-427X, DBLP ID：journals/jvca/TsurugaI18, J-Global ID：201702290122667042, SCOPUS ID：85047834195
• Error estimation for many-light rendering with supersampling.　　　　　　　　　　　　　　　
  Hirokazu Sakai; Kosuke Nabata; Shinya Yasuaki; Kei Iwasaki
  SIGGRAPH Asia 2018 Technical Briefs, Tokyo, Japan, December 04-07, 2018, First page：17:1-17:4, 2018, [Reviewed], [Last, Corresponding]
  ACM, English, International conference proceedings
  DOI：https://doi.org/10.1145/3283254.3283264
  DOI ID：10.1145/3283254.3283264, DBLP ID：conf/siggrapha/SakaiNYI18
• Fabricating reflectors for displaying multiple images.　　　　　　　　　　　　　　　
  Kaisei Sakurai; Yoshinori Dobashi; Kei Iwasaki; Tomoyuki Nishita
  ACM Transactions on Graphics, Volume：37, Number：4, First page：158:1-158:10, 2018, [Reviewed]
  A great deal of attention has been devoted to the fabrication of reflectors that can display different color images when viewed from different directions not only in industry but also for the arts. Although such reflectors have previously been successfully fabricated, the number of images displayed has been limited to two or they suffer from ghosting artifacts where mixed images appear. Furthermore, the previous methods need special hardware and/or materials to fabricate the reflectors. Thus, those techniques are not suitable for printing reflectors on everyday personal objects made of different materials, such as name cards, letter sheets, envelopes, and plastic cases. To overcome these limitations, we propose a method for fabricating reflectors using a standard ultraviolet printer (UV printer). UV printer can render a specified 2D color pattern on an arbitrary material and by overprinting the printed pattern can be raised, that is, the printed pattern becomes a microstructure having color and height. We propose using these microstructures to formulate a method for designing spatially varying reflections that can display different target images when viewed from different directions. The microstructure is calculated by minimizing an objective function that measures the differences between the intensities of the light reflected from the reflector and that of the target image. We show several fabricated reflectors to demonstrate the usefulness of the proposed method.
  English, Scientific journal
  DOI：https://doi.org/10.1145/3197517.3201400
  Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85056650065&origin=inward
  Scopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=85056650065&origin=inward
  DOI ID：10.1145/3197517.3201400, ISSN：0730-0301, eISSN：1557-7368, DBLP ID：journals/tog/SakuraiDIN18, SCOPUS ID：85056650065
• Inverse appearance modeling of interwoven cloth　　　　　　　　　　　　　　　
  Yoshinori Dobashi; Kei Iwasaki; Makoto Okabe; Takashi Ijiri; Hideki Todo
  Visual Computer, Volume：35, Number：2, First page：1, Last page：16, Dec. 2017, [Reviewed]
  This paper proposes an inverse approach for modeling the appearance of interwoven cloth. Creating the desired appearance in cloth is difficult because many factors, such as the type of thread and the weaving pattern, have to be considered. Design tools that enable the desired visual appearance of the cloth to be replicated are therefore beneficial for many computer graphics applications. In this paper, we focus on the design of the appearance of interwoven cloth whose reflectance properties are significantly affected by the weaving patterns. Although there are several systems that support editing of weaving patterns, they lack an inverse design tool that automatically determines the spatially varying bidirectional reflectance distribution function (BRDF) from the weaving patterns required to make the cloth display the desired appearance. We propose a method for computing the cloth BRDFs that can be used to display the desired image provided by the user. We formulate this problem as a cost minimization and solve it by computing the shortest path of a graph. We demonstrate the effectiveness of the method with several examples.
  Springer Verlag, English, Scientific journal
  DOI：https://doi.org/10.1007/s00371-017-1455-9
  DOI ID：10.1007/s00371-017-1455-9, ISSN：0178-2789, DBLP ID：journals/vc/DobashiIOIT19, SCOPUS ID：85036552122
• Example-based synthesis of three-dimensional clouds from photographs.
  Kei Iwasaki; Yoshinori Dobashi; Makoto Okabe
  Proceedings of the Computer Graphics International Conference, CGI 2017, Yokohama, Japan, June 27 - 30, 2017, First page：28:1-28:6, Jun. 2017, [Reviewed], [Lead]
  ACM, English, International conference proceedings
  DBLP ID：conf/cgi/IwasakiDO17
• Computer simulation of furniture layout when moving from one house to another　　　　　　　　　　　　　　　
  Takuya Yamakawa; Yoshinori Dobashi; Makoto Okabe; Kei Iwasaki; Tsuyoshi Yamamoto
  Proceedings - SCCG 2017: 33rd Spring Conference on Computer Graphics, Volume：2017-, First page：4:1-4:8, May 2017, [Reviewed]
  We present a system that automatically suggests the furniture layout when one moves into a new house, taking into account the furniture layout in the previous house. In our method, the input to our system comprises the floor plans of the previous and new houses, and the furniture layout in the previous house. The furniture layout for the whole house is suggested. This method builds on a previous furniture layout method with which the furniture layout for a single room only is computed. In this paper, we propose a new method that can suggest the furniture layout for multiple rooms in the new house. To deal with this problem, we took a heuristic approach in developing a cost function by adding some new cost functions to the previous method. We show various layouts computed using our method, which demonstrates the effectiveness of it.
  Association for Computing Machinery, Inc, English, International conference proceedings
  DOI：https://doi.org/10.1145/3154353.3154356
  DOI ID：10.1145/3154353.3154356, DBLP ID：conf/sccg/YamakawaDOIY17, SCOPUS ID：85044282465
• Visual simulation of clouds.　　　　　　　　　　　　　　　
  Yoshinori Dobashi; Kei Iwasaki; Yonghao Yue; Tomoyuki Nishita
  Visual Informatics, Volume：1, Number：1, First page：1, Last page：8, 2017, [Reviewed]
  English, Scientific journal
  DOI：https://doi.org/10.1016/j.visinf.2017.01.001
  DOI ID：10.1016/j.visinf.2017.01.001, DBLP ID：journals/vi/DobashiIYN17
• An Error Estimation Framework for Many-Light Rendering　　　　　　　　　　　　　　　
  K. Nabata; K. Iwasaki; Y. Dobashi; T. Nishita
  Computer Graphics Forum, Volume：35, Number：7, First page：431, Last page：439, Oct. 2016, [Reviewed], [Corresponding]
  Wiley, English, Scientific journal
  DOI：https://doi.org/10.1111/cgf.13040
  DOI ID：10.1111/cgf.13040, ISSN：0167-7055, eISSN：1467-8659, DBLP ID：journals/cgf/NabataIDN16, Web of Science ID：WOS:000388497400044
• Measuring microstructures using confocal laser scanning microscopy for estimating surface roughness　　　　　　　　　　　　　　　
  Yoshinori Dobashi; Takashi Ijiri; Hideki Todo; Kei Iwasaki; Makoto Okabe; Satoshi Nishimura
  SIGGRAPH 2016 - ACM SIGGRAPH 2016 Posters, First page：28:1, Jul. 2016, [Reviewed]
  Realistic image synthesis is an important research goal in computer graphics. One important factor to achieve this goal is a bidirectional reflectance distribution function (BRDF) that mainly governs an appearance of an object. Many BRDF models have therefore been developed. A physically-based BRDF based on microfacet theory [Cook and Torrance 1982] is widely used in many applications since it can produce highly realistic images. The microfacetbased BRDF consists of three terms
  a Fresnel, a normal distribution, and a geometric functions. There are many analytical and approximate models for each of these terms.
  Association for Computing Machinery, Inc, English, International conference proceedings
  DOI：https://doi.org/10.1145/2945078.2945106
  DOI ID：10.1145/2945078.2945106, DBLP ID：conf/siggraph/DobashiITION16, SCOPUS ID：84986000707
• Adaptive importance caching for many-light rendering　　　　　　　　　　　　　　　
  Hiroshi Yoshida; Kosuke Nabata; Kei Iwasaki; Yoshinori Dobashi; Tomoyuki Nishita
  Journal of WSCG, Volume：23, Number：1, First page：65, Last page：72, Aug. 2015, [Reviewed], [Corresponding]
  Importance sampling of virtual point lights (VPLs) is an efficient method for computing global illumination. The key to importance sampling is to construct the probability function, which is used to sample the VPLs, such that it is proportional to the distribution of contributions from all the VPLs. Importance caching records the contributions of all the VPLs at sparsely distributed cache points on the surfaces and the probability function is calculated by interpolating the cached data. Importance caching, however, distributes cache points randomly, which makes it difficult to obtain probability functions proportional to the contributions of VPLs where the variation in the VPL contribution at nearby cache points is large. This paper proposes an adaptive cache insertion method for VPL sampling. Our method exploits the spatial and directional correlations of shading points and surface normals to enhance the proportionality. The method detects cache points that have large variations in their contribution from VPLs and inserts additional cache points with a small overhead. In equal-time comparisons including cache point generation and rendering, we demonstrate that the images rendered with our method are less noisy compared to importance caching.
  Vaclav Skala Union Agency, English, Scientific journal
  ISSN：1213-6964, SCOPUS ID：84938220273
• Incompressibility-preserving deformation for fluid flows using vector potentials　　　　　　　　　　　　　　　
  Syuhei Sato; Yoshinori Dobashi; Yonghao Yue; Kei Iwasaki; Tomoyuki Nishita
  VISUAL COMPUTER, Volume：31, Number：6-8, First page：959, Last page：965, Jun. 2015, [Reviewed]
  Physically based fluid simulations usually require expensive computation cost for creating realistic animations. We present a technique that allows the user to create various fluid animations from an input fluid animation sequence, without the need for repeatedly performing simulations. Our system allows the user to deform the flow field in order to edit the overall fluid behavior. In order to maintain plausible physical behavior, we ensure the incompressibility to guarantee the mass conservation. We use a vector potential for representing the flowfields to realize such incompressibility-preserving deformations. Our method first computes (time-varying) vector potentials from the input velocity field sequence. Then, the user deforms the vector potential, and the system computes the deformed velocity field by taking the curl operator on the vector potential. The incompressibility is thus obtained by construction. We show various examples to demonstrate the usefulness of our method.
  SPRINGER, English, Scientific journal
  DOI：https://doi.org/10.1007/s00371-015-1122-y
  DOI ID：10.1007/s00371-015-1122-y, ISSN：0178-2789, eISSN：1432-2315, DBLP ID：journals/vc/SatoDYIN15, Web of Science ID：WOS:000357487500021
• An Interactive Editing System for Visual Appearances of Fire and Explosions.　　　　　　　　　　　　　　　
  Yoshinori Dobashi; Yuhei Shibukawa; Munehiro Tada; Syuhei Sato; Kei Iwasaki; Tsuyoshi Yamamoto
  Eurographics 2015 - Short Papers, Zurich, Switzerland, May 4-8, 2015., First page：49, Last page：52, 2015, [Reviewed]
  Eurographics Association, International conference proceedings
  DOI：https://doi.org/10.2312/egsh.20151012
  DOI ID：10.2312/egsh.20151012, DBLP ID：conf/eurographics/DobashiSTSIY15
• Deformation of 2D flow fields using stream functions　　　　　　　　　　　　　　　
  Syuhei Sato; Yoshinori Dobashi; Kei Iwasaki; Tsuyoshi Yamamoto; Tomoyuki Nishita
  SIGGRAPH Asia 2014 Technical Briefs, SA 2014, First page：4:1-4:4, Nov. 2014, [Reviewed]
  Recently, visual simulation of fluids has become an important element in many applications, such as movies and computer games. These fluid animations are usually created by physically-based fluid simulation. However, the simulation often requires very expensive computational cost for creating realistic fluid animations. Therefore, when the user tries to create various fluid animations, he or she must execute fluid simulation repeatedly, which requires a prohibitive computational time. To address this problem, this paper proposes a method for deforming velocity fields of fluids while preserving the divergence-free condition. In this paper, we focus on grid-based 2D fluid simulations. Our system allows the user to interactively create various fluid animations from a single set of velocity fields generated by the fluid simulation. In a preprocess, our method converts the input velocity fields into scalar fields representing the stream functions. At run-time, the user deforms the grid representing the scalar stream functions and the deformed velocity fields are then obtained by applying a curl operator to the deformed scalar stream functions. The velocity fields obtained by this process naturally perseveres the divergence-free condition. For the deformation of the grid, we use a method based on Moving Least Squares. The usefulness of our method is demonstrated by several examples.
  Association for Computing Machinery, Inc, English, International conference proceedings
  DOI：https://doi.org/10.1145/2669024.2669039
  DOI ID：10.1145/2669024.2669039, DBLP ID：conf/siggraph/SatoDIYN14, SCOPUS ID：84926117841
• An Optimization Approach for Designing Fluid Flow Fields　　　　　　　　　　　　　　　
  Syuhei Sato; Yoshinori Dobashi; Kei Iwasaki; Hiroyuki Ochiai; Tsuyoshi Yamamoto; Tomoyuki Nishita
  Computer Graphics International 2014 short paper, Jun. 2014, [Reviewed]
  English, International conference proceedings
• Poisson-Based Continuous Surface Generation for Goal-Based Caustics　　　　　　　　　　　　　　　
  Yonghao Yue; Kei Iwasaki; Bing-Yu Chen; Yoshinori Dobashi; Tomoyuki Nishita
  ACM Transactions on Graphics, Volume：33, Number：3, First page：31:1-31:7, May 2014, [Reviewed]
  We present a technique for computing the shape of a transparent object that can generate user-defined caustic patterns. The surface of the object generated using our method is smooth. Thanks to this property, the resulting caustic pattern is smooth, natural, and highly detailed compared to the results obtained using previous methods. Our method consists of two processes. First, we use a differential geometry approach to compute a smooth mapping between the distributions of the incident light and the light reaching the screen. Second, we utilize this mapping to compute the surface of the object. We solve Poisson's equation to compute both the mapping and the surface of the object.
  ASSOC COMPUTING MACHINERY, English, Scientific journal
  DOI：https://doi.org/10.1145/2580946
  DOI ID：10.1145/2580946, ISSN：0730-0301, eISSN：1557-7368, DBLP ID：journals/tog/YueICDN14, Web of Science ID：WOS:000337057200010
• Interactive cloth rendering of microcylinder appearance model under environment lighting　　　　　　　　　　　　　　　
  K. Iwasaki; K. Mizutani; Y. Dobasbi; T. Nisbita
  Computer Graphics Forum, Volume：33, Number：2, First page：333, Last page：340, 2014, [Reviewed]
  This paper proposes an interactive rendering method of cloth fabrics under environment lighting. The outgoing radiance from cloth fabrics in the microcylinder model is calculated by integrating the product of the distant environment lighting, the visibility function, the weighting function that includes shadowing/masking effects of threads, and the light scattering function of threads. The radiance calculation at each shading point of the cloth fabrics is simplified to a linear combination of triple product integrals of two circular Gaussians and the visibility function, multiplied by precomputed spherical Gaussian convolutions of the weighting function. We propose an efficient calculation method of the triple product of two circular Gaussians and the visibility function by using the gradient of signed distance function to the visibility boundary where the binary visibility changes in the angular domain of the hemisphere. Our GPU implementation enables interactive rendering of static cloth fabrics with dynamic viewpoints and lighting. In addition, interactive editing of parameters for the scattering function (e.g. thread's albedo) that controls the visual appearances of cloth fabrics can be achieved. © 2014 The Author(s) Computer Graphics Forum © 2014 The Eurographics Association and John Wiley &
  Sons Ltd. Published by John Wiley &
  Sons Ltd.
  Blackwell Publishing Ltd, English, Scientific journal
  DOI：https://doi.org/10.1111/cgf.12302
  DOI ID：10.1111/cgf.12302, ISSN：1467-8659, SCOPUS ID：84901851048
• Generating various flow fields using principal component analysis　　　　　　　　　　　　　　　
  Syuhei Sato; Yoshinori Dobashi; Kei Iwasaki; Hiroyuki Ochiai; Tsuyoshi Yamamoto; Tomoyuki Nishita
  ACM SIGGRAPH 2014 Posters, SIGGRAPH 2014, First page：9:1, 2014, [Reviewed]
  Association for Computing Machinery, English, International conference proceedings
  DOI：https://doi.org/10.1145/2614217.2630575
  DOI ID：10.1145/2614217.2630575, DBLP ID：conf/siggraph/SatoDIOYN14, SCOPUS ID：84905687695
• A simplified plane-parallel scattering model for rendering densely distributed objects such as foliage　　　　　　　　　　　　　　　
  Mikio Shinya; Yoshinori Dobashi; Kei Iwasaki; Michio Shiraishi; Tomoyuki Nishita
  Journal of Information Processing, Volume：21, Number：2, First page：349, Last page：357, Apr. 2013, [Reviewed]
  Fast computation of multiple reflections and scattering among complex objects is very important in photorealistic rendering. This paper applies the plane-parallel scattering theory to the rendering of densely distributed objects such as trees. We propose a simplified plane-parallel scattering model that has very simple analytic solutions, allowing efficient evaluation of multiple scattering. A geometric compensation method is also introduced to cope with the infinite plane condition, required by the plane-parallel model. The scattering model was successfully applied to tree rendering. Comparison with a Monte Carlo method was made and reasonable agreement was confirmed. A rendering system based on the model was implemented and multiple inter-reflections were effectively obtained. The view-independent feature of the model allows fast display of scenes. The pre-computation is also modest, permitting interactive control of lighting conditions. © 2013 Information Processing Society of Japan.
  English, Scientific journal
  DOI：https://doi.org/10.2197/ipsjjip.21.349
  DOI ID：10.2197/ipsjjip.21.349, ISSN：0387-5806, DBLP ID：journals/jip/ShinyaDISN13, SCOPUS ID：84876255558
• A Simplified Plane-parallel Scattering Model for Rendering Densely Distributed Objects such as Foliage　　　　　　　　　　　　　　　
  Shinya Mikio; Dobashi Yoshinori; Iwasaki Kei; Shiraishi Michio; Nishita Tomoyuki
  IMT, Volume：8, Number：2, First page：380, Last page：388, 2013, [Reviewed]
  Fast computation of multiple reflections and scattering among complex objects is very important in photorealistic rendering. This paper applies the plane-parallel scattering theory to the rendering of densely distributed objects such as trees. We propose a simplified plane-parallel scattering model that has very simple analytic solutions, allowing efficient evaluation of multiple scattering. A geometric compensation method is also introduced to cope with the infinite plane condition, required by the plane-parallel model. The scattering model was successfully applied to tree rendering. Comparison with a Monte Carlo method was made and reasonable agreement was confirmed. A rendering system based on the model was implemented and multiple inter-reflections were effectively obtained. The view-independent feature of the model allows fast display of scenes. The pre-computation is also modest, permitting interactive control of lighting conditions.
  Information and Media Technologies Editorial Board, English
  DOI：https://doi.org/10.11185/imt.8.380
  DOI ID：10.11185/imt.8.380, ISSN：1881-0896, CiNii Articles ID：130003366955
• Replica exchange light transport on relaxed distributions　　　　　　　　　　　　　　　
  Hisanari Otsu; Yonghao Yue; Qiming Hou; Kei Iwasaki; Yoshinori Dobashi; Tomoyuki Nishita
  ACM SIGGRAPH 2013 Posters, SIGGRAPH 2013, First page：106, 2013, [Reviewed]
  Developing a robust method for computing global illumination is a challenging problem. A Markov chain Monte Carlo (MCMC) method, like [Jakob and Marschner 2012], samples the light path space with a probability proportional to the per-path contribution, by successively mutating path samples (e.g., perturbing a reflection direction). In practice, a path sample could get stuck in a high energy peak for multiple mutations, resulting in a bright spot artifact. To resolve this problem, we present a new unbiased rendering framework based on a replica exchange technique [Kitaoka et al. 2009], a variant of MCMC technique. A replica exchange technique incorporates a set of different distributions. We propose to introduce a set of relaxed distributions, which are beneficial for reducing the chance of getting stuck.
  ACM, English, International conference proceedings
  DOI：https://doi.org/10.1145/2503385.2503501
  DOI ID：10.1145/2503385.2503501, DBLP ID：conf/siggraph/OtsuYHIDN13, SCOPUS ID：84881594784
• Visual simulation of glazed frost.　　　　　　　　　　　　　　　
  Tomokazu Ishikawa; Yoshinori Dobashi; Yonghao Yue; Masanori Kakimoto; Taichi Watanabe; Kunio Kondo; Kei Iwasaki; Tomoyuki Nishita
  Special Interest Group on Computer Graphics and Interactive Techniques Conference, SIGGRAPH '13, Anaheim, CA, USA, July 21-25, 2013, Poster Proceedings, First page：14, Last page：14, 2013, [Reviewed]
  ACM, International conference proceedings
  DOI：https://doi.org/10.1145/2503385.2503400
  Dblp：https://dblp.uni-trier.de/db/conf/siggraph/siggraph2013posters.html#IshikawaDYKWKIN13
  Dblp Cross Ref：https://dblp.uni-trier.de/conf/siggraph/2013posters
  DOI ID：10.1145/2503385.2503400, DBLP ID：conf/siggraph/IshikawaDYKWKIN13
• Generating flow fields variations by modulating amplitude and resizing simulation space　　　　　　　　　　　　　　　
  Syuhei Sato; Yoshinori Dobashi; Kei Iwasaki; Hiroyuki Ochiai; Tsuyoshi Yamamoto
  SIGGRAPH Asia 2013 Technical Briefs, SA 2013, First page：13:1-13:4, 2013, [Reviewed]
  The visual simulation of fluids has become an important element in many applications, such as movies and computer games. In these applications, large-scale fluid scenes, such as fire in a village, are often simulated by repeatedly rendering multiple small-scale fluid flows. In these cases, animators are requested to generate many variations of a small-scale fluid flow. This paper presents a method to help animators meet such requirements. Our method enables the user to generate flow field variations from a single simulated dataset obtained by fluid simulation. The variations are generated in both the frequency and spatial domains. Fluid velocity fields are represented using Laplacian eigenfunctions which ensure that the flow field is always incompressible. In generating the variations in the frequency domain, we modulate the coefficients (amplitudes) of the basis functions. To generate variations in the spatial domain, our system expands or contracts the simulation space, then the flow is calculated by solving a minimization problem subject to the resized velocity field. Using our method, the user can easily create various animations from a single dataset calculated by fluid simulation. 2013 Copyright held by the Owner/Author.
  ACM, English, International conference proceedings
  DOI：https://doi.org/10.1145/2542355.2542371
  DOI ID：10.1145/2542355.2542371, DBLP ID：conf/siggraph/SatoDIOY13, SCOPUS ID：84890906421
• Efficient Divide-And-Conquer Ray Tracing using Ray Sampling.
  Kosuke Nabata; Kei Iwasaki; Yoshinori Dobashi; Tomoyuki Nishita
  High-Performance Graphics 2013, Anaheim, California, USA, July 19-21, 2013. Proceedings, First page：129, Last page：136, 2013, [Reviewed]
  ACM
  DBLP ID：conf/egh/NabataIDN13
• Interactive Bi-scale Editing of Highly Glossy Materials　　　　　　　　　　　　　　　
  Kei Iwasaki; Yoshinori Dobashi; Tomoyuki Nishita
  ACM Transactions on Graphics, Volume：31, Number：6, First page：144:1-144:7, Nov. 2012, [Reviewed]
  We present a new technique for bi-scale material editing using Spherical Gaussians (SGs). To represent large-scale appearances, an effective BRDF that is the average reflectance of small-scale details is used. The effective BRDF is calculated from the integral of the product of the Bidirectional Visible Normal Distribution (BVNDF) and BRDFs of small-scale geometry. Our method represents the BVNDF with a sum of SGs, which can be calculated on-the-fly, enabling interactive editing of small-scale geometry. By representing small-scale BRDFs with a sum of SGs, effective BRDFs can be calculated analytically by convolving the SGs for BVNDF and BRDF. We propose a new SG representation based on convolution of two SGs, which allows real-time rendering of effective BRDFs under all-frequency environment lighting and real-time editing of small-scale BRDFs. In contrast to the previous method, our method does not require extensive precomputation time and large volume of precomputed data per single BRDF, which makes it possible to implement our method on a GPU, resulting in real-time rendering.
  ASSOC COMPUTING MACHINERY, English, Scientific journal
  DOI：https://doi.org/10.1145/2366145.2366163
  DOI ID：10.1145/2366145.2366163, ISSN：0730-0301, eISSN：1557-7368, DBLP ID：journals/tog/IwasakiDN12, Web of Science ID：WOS:000311298900018
• Real-time Rendering of Dynamic Scenes Using Sphere Set Approximation and Spherical Signed Distance Function　　　　　　　　　　　　　　　
  Wataru Furuya; Kei Iwasaki; Yoshinori Dobashi; Tomoyuki Nishita
  IPSJ Journal, Volume：53, Number：7, First page：1905, Last page：1914, Jul. 2012, [Reviewed], [Corresponding]
  We propose a real-time rendering method for dynamic scenes under all-frequency environmental lighting. To render the object surfaces illuminated by environmental lighting, the product of the environmental lighting, the visibility function at each shading point on the object surfaces, and the BRDF is integrated. Our method represents the environmental lighting and the BRDFs with spherical Gaussians and represents the visibility functions with spherical signed distance functions (SSDFs). Although these representations enable us to render scenes under all-frequency lighting in real-time, the p...
  Information Processing Society of Japan (IPSJ), Japanese
  ISSN：0387-5806, CiNii Articles ID：110009423560, CiNii Books ID：AN00116647
• Real-time Rendering of Dynamic Scenes under All-frequency Lighting using Integral Spherical Gaussian　　　　　　　　　　　　　　　
  Kei Iwasaki; Wataru Furuya; Yoshinori Dobashi; Tomoyuki Nishita
  Computer Graphics Forum, Volume：31, Number：2, First page：727, Last page：734, May 2012, [Reviewed], [Lead, Corresponding]
  We propose an efficient rendering method for dynamic scenes under all-frequency environmental lighting. To render the surfaces of objects illuminated by distant environmental lighting, the triple product of the lighting, the visibility function and the BRDF is integrated at each shading point on the surfaces. Our method represents the environmental lighting and the BRDF with a linear combination of spherical Gaussians, replacing the integral of the triple product with the sum of the integrals of spherical Gaussians over the visible region of the hemisphere. We propose a new form of spherical Gaussian, the integral spherical Gaussian, that enables the fast and accurate integration of spherical Gaussians with various sharpness over the visible region on the hemisphere. The integral spherical Gaussian simplifies the integration to a sum of four pre-integrated values, which are easily evaluated on-the-fly. With a combination of a set of spheres to approximate object geometries and the integral spherical Gaussian, our method can render object surfaces very efficiently. Our GPU implementation demonstrates real-time rendering of dynamic scenes with dynamic viewpoints, lighting, and BRDFs.
  WILEY-BLACKWELL, English, Scientific journal
  DOI：https://doi.org/10.1111/j.1467-8659.2012.03052.x
  DOI ID：10.1111/j.1467-8659.2012.03052.x, ISSN：0167-7055, DBLP ID：journals/cgf/IwasakiFDN12, Web of Science ID：WOS:000306181700022
• Pixel Art with Refracted Light by Rearrangeable Sticks　　　　　　　　　　　　　　　
  Yonghao Yue; Kei Iwasaki; Bing-Yu Chen; Yoshinori Dobashi; Tomoyuki Nishita
  Computer Graphics Forum, Volume：31, Number：2, First page：575, Last page：582, May 2012, [Reviewed]
  Pixel art is a kind of digital art that through per-pixel manipulation enables production of a diverse array of artistic images. In this paper, we present a new way for people to experience and express pixel art. Our digital art consists of a set of sticks made of acrylate resin, each of which refracts light from a parallel light source, in certain directions. Artistic users are able to easily rearrange these sticks and view their digital art through the refracted light projection on any planar surface. As we demonstrate in this paper, a user can generate various artistic images using only a single set of sticks. We additionally envision that our pixel art with rearrangeable sticks would have great entertainment appeal, e. g., as an art puzzle.
  WILEY-BLACKWELL, English, Scientific journal
  DOI：https://doi.org/10.1111/j.1467-8659.2012.03036.x
  DOI ID：10.1111/j.1467-8659.2012.03036.x, ISSN：0167-7055, DBLP ID：journals/cgf/YueICDN12, Web of Science ID：WOS:000306181700006
• Visual simulation of freezing ice with air bubbles　　　　　　　　　　　　　　　
  Takanori Nishino; Kei Iwasaki; Yoshinori Dobashi; Tomoyuki Nishita
  SIGGRAPH Asia 2012 Technical Briefs, SA 2012, 2012, [Reviewed], [Corresponding]
  Ice often contains small air bubbles that are dissolved air exhausted from water-ice interface. Depicting these air bubbles with various sizes enhances the realism of ice. This paper proposes a fast simulation method of freezing ice taking into account air bubbles. Our method introduces a physically-based calculation method of the sizes of air bubbles based on the freezing velocity and pressure. In contrast to the previous method, our method can represent numerous small bubbles that cannot be represented by using the resolutions of simulation grids. The computations of heat transfer, tracking of water-ice interface, and generation of bubbles are accelerated by implementing our method using CUDA. Our method achieves the freezing simulation and bubble generation at interactive frame-rates. © 2012 ACM.
  English, International conference proceedings
  DOI：https://doi.org/10.1145/2407746.2407747
  DOI ID：10.1145/2407746.2407747, SCOPUS ID：84871773889
• Visual Simulation of Magnetic Fluid Using a Procedural Approach for Spikes Shape.　　　　　　　　　　　　　　　
  Tomokazu Ishikawa; Yonghao Yue; Kei Iwasaki; Yoshinori Dobashi; Tomoyuki Nishita
  Computer Vision, Imaging and Computer Graphics. Theory and Application - 7th International Joint Conference, VISIGRAPP 2012, Rome, Italy, February 24-26, 2012, Revised Selected Papers, First page：112, Last page：126, 2012, [Reviewed]
  Springer, International conference proceedings
  DOI：https://doi.org/10.1007/978-3-642-38241-3_8
  Dblp：https://dblp.uni-trier.de/db/conf/visapp/visigrapp2012.html#IshikawaYIDN12
  Dblp Cross Ref：https://dblp.uni-trier.de/conf/visapp/2012-s
  DOI ID：10.1007/978-3-642-38241-3_8, DBLP ID：conf/visapp/IshikawaYIDN12
• Visual Simulation of Magnetic Fluids.　　　　　　　　　　　　　　　
  Tomokazu Ishikawa; Yonghao Yue; Kei Iwasaki; Yoshinori Dobashi; Tomoyuki Nishita
  GRAPP & IVAPP 2012: Proceedings of the International Conference on Computer Graphics Theory and Applications and International Conference on Information Visualization Theory and Applications, Rome, Italy, 24-26 February, 2012, First page：319, Last page：327, 2012, [Reviewed]
  SciTePress, International conference proceedings
  Dblp：https://dblp.uni-trier.de/db/conf/grapp/grapp2012.html#IshikawaYIDN12
  Dblp Cross Ref：https://dblp.uni-trier.de/conf/grapp/2012
  DBLP ID：conf/grapp/IshikawaYIDN12
• Toward Optimal Space Partitioning for Unbiased, Adaptive Free Path Sampling of Inhomogeneous Participating Media　　　　　　　　　　　　　　　
  Yonghao Yue; Kei Iwasaki; Bing-Yu Chen; Yoshinori Dobashi; Tomoyuki Nishita
  Computer Graphics Forum, Volume：30, Number：7, First page：1911, Last page：1919, Sep. 2011, [Reviewed]
  Photo-realistic rendering of inhomogeneous participating media with light scattering in consideration is important in computer graphics, and is typically computed using Monte Carlo based methods. The key technique in such methods is the free path sampling, which is used for determining the distance (free path) between successive scattering events. Recently, it has been shown that efficient and unbiased free path sampling methods can be constructed based on Woodcock tracking. The key concept for improving the efficiency is to utilize space partitioning (e.g., kd-tree or uniform grid), and a better space partitioning scheme is important for better sampling efficiency. Thus, an estimation framework for investigating the gain in sampling efficiency is important for determining how to partition the space. However, currently, there is no estimation framework that works in 3D space. In this paper, we propose a new estimation framework to overcome this problem. Using our framework, we can analytically estimate the sampling efficiency for any typical partitioned space. Conversely, we can also use this estimation framework for determining the optimal space partitioning. As an application, we show that new space partitioning schemes can be constructed using our estimation framework. Moreover, we show that the differences in the performances using different schemes can be predicted fairly well using our estimation framework.
  WILEY-BLACKWELL, English, Scientific journal
  DOI：https://doi.org/10.1111/j.1467-8659.2011.02049.x
  DOI ID：10.1111/j.1467-8659.2011.02049.x, ISSN：0167-7055, DBLP ID：journals/cgf/YueICDN11, Web of Science ID：WOS:000296915400006
• Efficient calculation method of spherical signed distance function for real-time rendering of dynamic scenes　　　　　　　　　　　　　　　
  Wataru Furuya; Kei Iwasaki; Yoshinori Dobashi; Tomoyuki Nishita
  SIGGRAPH Asia 2011 Sketches, SA'11, 2011, [Reviewed]
  Real-time rendering of dynamic scenes illuminated by complex, all-frequency lighting with highly glossy BRDFs remains a challenging problem. Although several methods have been proposed to render dynamic scenes, these methods can not handle deformable objects [Zhou et al. 2005], all-frequency lighting [Ren et al. 2006
  Nowrouzezahrai et al. 2009], or highly glossy BRDFs [Annen et al. 2008].
  English, International conference proceedings
  DOI：https://doi.org/10.1145/2077378.2077393
  DOI ID：10.1145/2077378.2077393, SCOPUS ID：84855474622
• Modeling of aurora borealis using the observed data.　　　　　　　　　　　　　　　
  Tomokazu Ishikawa; Yonghao Yue; Kei Iwasaki; Yoshinori Dobashi; Tomoyuki Nishita
  Spring Conference on Computer Graphics, SCCG '11, Vininé, Slovakia, April 28-30, 2011, First page：13, Last page：16, 2011, [Reviewed]
  ACM, International conference proceedings
  DOI：https://doi.org/10.1145/2461217.2461220
  Dblp：https://dblp.uni-trier.de/db/conf/sccg/sccg2011.html#IshikawaYIDN11
  Dblp Cross Ref：https://dblp.uni-trier.de/conf/sccg/2011
  DOI ID：10.1145/2461217.2461220, DBLP ID：conf/sccg/IshikawaYIDN11
• Unbiased, Adaptive Stochastic Sampling for Rendering Inhomogeneous Participating Media　　　　　　　　　　　　　　　
  Yonghao Yue; Kei Iwasaki; Bing-Yu Chen; Yoshinori Dobashi; Tomoyuki Nishita
  ACM Transactions on Graphics, Volume：29, Number：6, First page：177, Dec. 2010, [Reviewed]
  Realistic rendering of participating media is one of the major subjects in computer graphics. Monte Carlo techniques are widely used for realistic rendering because they provide unbiased solutions, which converge to exact solutions. Methods based on Monte Carlo techniques generate a number of light paths, each of which consists of a set of randomly selected scattering events. Finding a new scattering event requires free path sampling to determine the distance from the previous scattering event, and is usually a time-consuming process for inhomogeneous participating media. To address this problem, we propose an adaptive and unbiased sampling technique using kd-tree based space partitioning. A key contribution of our method is an automatic scheme that partitions the spatial domain into sub-spaces (partitions) based on a cost model that evaluates the expected sampling cost. The magnitude of performance gain obtained by our method becomes larger for more inhomogeneous media, and rises to two orders compared to traditional free path sampling techniques.
  ASSOC COMPUTING MACHINERY, English, Scientific journal
  DOI：https://doi.org/10.1145/1866158.1866199
  DOI ID：10.1145/1866158.1866199, ISSN：0730-0301, DBLP ID：journals/tog/YueICDN10, Web of Science ID：WOS:000284943000041
• A simplified plane-parallel scattering model and its application to hair rendering　　　　　　　　　　　　　　　
  Mikio Shinya; Mishio Shiraishi; Yoshinori Dobashi; Kei Iwasaki; Tomoyuki Nishita
  Proceedings - Pacific Conference on Computer Graphics and Applications, First page：85, Last page：92, 2010, [Reviewed]
  Fast computation of multiple light reflections and scattering among complex objects is very important in photorealistic rendering. This paper applies the plane-parallel scattering theory to the rendering of densely distributed objects such as hairs. We propose a simplified plane-parallel model that has very simple analytic solutions. This allows us to deal with multiple scattering phenomena in hair under ambient and area light illumination. The model was successfully applied to hair rendering, and experiments demonstrated the efficiency of the proposed method. © 2010 IEEE.
  English, International conference proceedings
  DOI：https://doi.org/10.1109/PacificGraphics.2010.19
  DOI ID：10.1109/PacificGraphics.2010.19, ISSN：1550-4085, SCOPUS ID：79951714468
• Interactive Lighting and Material Design System for Cyber Worlds　　　　　　　　　　　　　　　
  Kei Iwasaki; Yoshinori Dobashi; Tomoyuki Nishita
  2010 INTERNATIONAL CONFERENCE ON CYBERWORLDS (CW 2010), First page：331, Last page：337, 2010, [Reviewed], [Lead]
  Interactive rendering under complex real world illumination is essential for many applications such as material design, lighting design, and virtual realities. For such applications, interactive manipulations of viewpoints, lighting, BRDFs, and positions of objects are beneficial to designers and users. This paper proposes a system that acquires complex, all-frequency lighting environments and renders dynamic scenes under captured illumination, for lighting and material design applications in cyber worlds. To capture real world lighting environments easily, our method uses a camera equipped with a cellular phone. To handle dynamic scenes of rigid objects and dynamic BRDFs, our method decomposes the visibility function at each vertex of each object into the occlusion due to the object itself and occlusions due to other objects, which are represented by a nonlinear piecewise constant approximation, called cuts. Our method proposes a compact cut representation and efficient algorithm for cut operations. By using our system, interactive manipulation of positions of objects and realtime rendering with dynamic viewpoints, lighting, and BRDFs can be achieved.
  IEEE, English, International conference proceedings
  DOI：https://doi.org/10.1109/CW.2010.54
  DOI ID：10.1109/CW.2010.54, DBLP ID：conf/cw/IwasakiDN10, Web of Science ID：WOS:000291875400049
• Fast Particle-based Visual Simulation of Ice Melting　　　　　　　　　　　　　　　
  K. Iwasaki; H. Uchida; Y. Dobashi; T. Nishita
  Computer Graphics Forum, Volume：29, Number：7, First page：2215, Last page：2223, 2010, [Reviewed], [Lead, Corresponding]
  The visual simulation of natural phenomena has been widely studied. Although several methods have been proposed to simulate melting, the flows of meltwater drops on the surfaces of objects are not taken into account. In this paper, we propose a particle-based method for the simulation of the melting and freezing of ice objects and the interactions between ice and fluids. To simulate the flow of meltwater on ice and the formation of water droplets, a simple interfacial tension is proposed, which can be easily incorporated into common particle-based simulation methods such as Smoothed Particle Hydrodynamics. The computations of heat transfer, the phase transition between ice and water, the interactions between ice and fluids, and the separation of ice due to melting are further accelerated by implementing our method using CUDA. We demonstrate our simulation and rendering method for depicting melting ice at interactive frame-rates.
  WILEY-BLACKWELL, English, Scientific journal
  DOI：https://doi.org/10.1111/j.1467-8659.2010.01810.x
  DOI ID：10.1111/j.1467-8659.2010.01810.x, ISSN：0167-7055, eISSN：1467-8659, DBLP ID：journals/cgf/IwasakiUDN10, Web of Science ID：WOS:000283159400024
• Interactive Rendering of Interior Scenes with Dynamic Environment Illumination　　　　　　　　　　　　　　　
  Yonghao Yue; Kei Iwasaki; Bing-Yu Chen; Yoshinori Dobashi; Tomoyuki Nishita
  Computer Graphics Forum, Volume：28, Number：7, First page：1935, Last page：1944, Oct. 2009, [Reviewed]
  A rendering system for interior scenes is proposed in this paper The light reaches the interior scene, usually through small regions, such as windows or abat-jours, which we call portals. To provide a solution, suitable for rendering interior scenes with portals, we extend the traditional precomputed radiance transfer approaches. In our approach, a bounding sphere, which we call a shell, of the interior centered at each portal, is created and the light transferred from the shell towards the interior through the portal is precomputed. Each shell acts as an environment light source and its intensity distribution is determined by, rendering images of the scene, viewed from the center of the shell. By updating the intensity, distribution of the shell at each frame, we are able to handle dynamic objects outside the shells. The material of the portals can also be modified at run time (e.g. changing front transparent glass to frosted glass). Several applications are shown, including the illumination of a cathedral, lit by skylight at different times of a day, and a car, running in a town, at interactive frame rates, with a dynamic viewpoint.
  WILEY-BLACKWELL, English, Scientific journal
  DOI：https://doi.org/10.1111/j.1467-8659.2009.01572.x
  DOI ID：10.1111/j.1467-8659.2009.01572.x, ISSN：0167-7055, DBLP ID：journals/cgf/YueICDN09, Web of Science ID：WOS:000270778100023
• Inverse Problem Approach for BRDF Modeling　　　　　　　　　　　　　　　
  Kei Iwasaki; Yoshinori Dobashi; Tomoyuki Nishita
  IPSJ Journal, Volume：50, Number：8, First page：1917, Last page：1925, Aug. 2009
  This paper presents a BRDF modeling method, based on an inverse problem approach. Our method calculates BRDFs to match the appearance of the object specified by the user. By representing BRDFs by a linear combination of basis functions, outgoing radiances of the object surface can be represented using basis functions. The calculation of the desired BRDF results from calculating the corresponding coefficients of basis functions that minimize the sum of differences between the outgoing radiances, represented using basis functions and user specified radiances. The properties that BRDFs must sa...
  Information Processing Society of Japan (IPSJ), Japanese
  ISSN：0387-5806, CiNii Articles ID：110007970480
• Rendering Translucent Materials with Plane-parallel Solution　　　　　　　　　　　　　　　
  Mikio Shinya; Michio Shiraishi; Yoshinori Dobashi; Kei Iwasaki; Tomoyuki Nishita
  IPSJ Journal, Volume：50, Number：6, First page：1668, Last page：1678, Jun. 2009
  Lighting simulation is very important in realistic image synthesis, and the simulation of subsurface scattering has recently attracted much attention. Although the dipole/multipole model has succeeded in creating realistic images, it is still difficult to deal with volumetric features in subsurface scattering, which is important when rendering optically thin objects. This paper proposes a novel rendering method that utilizes the plane-parallel solution and the ray-marching method. The ray-marching method has been used to calculate single scattering solutions, and the plane-parallel solution...
  Information Processing Society of Japan (IPSJ), English
  ISSN：0387-5806, CiNii Articles ID：110007970456
• Rendering Translucent Materials with Plane-parallel Solution　　　　　　　　　　　　　　　
  Shinya Mikio; Shiraishi Michio; Dobashi Yoshinori; Iwasaki Kei; Nishita Tomoyuki
  Information and Media Technologies, Volume：4, Number：3, First page：655, Last page：665, 2009
  Lighting simulation is very important in realistic image synthesis, and the simulation of subsurface scattering has recently attracted much attention. Although the dipole/multipole model has succeeded in creating realistic images, it is still difficult to deal with volumetric features in subsurface scattering, which is important when rendering optically thin objects. This paper proposes a novel rendering method that utilizes the plane-parallel solution and the ray-marching method. The ray-marching method has been used to calculate single scattering solutions, and the plane-parallel solution has been adopted to calculate BRDFs. By combining these techniques, the proposed method efficiently captures volumetric features in multiple subsurface scattering events. In our experiments, the proposed method demonstrated a performance superior to that of previous methods in terms of accuracy.
  Information and Media Technologies Editorial Board, English
  DOI：https://doi.org/10.11185/imt.4.655
  DOI ID：10.11185/imt.4.655, CiNii Articles ID：130000120701
• AN INVERSE PROBLEM APPROACH TO BRDF MODELING　　　　　　　　　　　　　　　
  Kei Iwasaki; Yoshinori Dobashi; Fujiichi Yoshimoto; Tomoyuki Nishita
  GRAPP 2009: PROCEEDINGS OF THE FOURTH INTERNATIONAL CONFERENCE ON COMPUTER GRAPHICS THEORY AND APPLICATIONS, First page：129, Last page：+, 2009, [Reviewed]
  This paper presents a BRDF modeling method, based on an inverse problem approach. Our method calculates BRDFs to match the appearance of the object specified by the user. By representing BRDFs by a linear combination of basis functions, outgoing radiances of the object surface can be represented using basis functions. The calculation of the desired BRDF results from calculating the corresponding coefficients of basis functions that minimize the sum of differences between the outgoing radiances, represented using basis functions and user specified radiances. The properties that BRDFs must satisfy are described by linear constraint conditions. This minimization problem can be solved, interactively, using a linearly constrained least squares approach. Thus, our method allows the user to design BRDFs directly, under fixed complex lighting and viewpoint, and to view the rendering results interactively, under dynamic lighting and viewpoint.
  INSTICC-INST SYST TECHNOLOGIES INFORMATION CONTROL & COMMUNICATION, English, International conference proceedings
  DBLP ID：conf/grapp/IwasakiDYN09, Web of Science ID：WOS:000267137900020
• Rendering translucent materials with plane-parallel solution　　　　　　　　　　　　　　　
  Mikio Shinya; Michio Shiraishi; Yoshinori Dobashi; Kei Iwasaki; Tomoyuki Nishita
  Journal of Information Processing, Volume：17, First page：180, Last page：190, 2009, [Reviewed]
  Lighting simulation is very important in realistic image synthesis, and the simulation of subsurface scattering has recently attracted much attention. Although the dipole/multipole model has succeeded in creating realistic images, it is still difficult to deal with volumetric features in subsurface scattering, which is important when rendering optically thin objects. This paper proposes a novel rendering method that utilizes the plane-parallel solution and the ray-marching method. The ray-marching method has been used to calculate single scattering solutions, and the plane-parallel solution has been adopted to calculate BRDFs. By combining these techniques, the proposed method efficiently captures volumetric features in multiple subsurface scattering events. In our experiments, the proposed method demonstrated a performance superior to that of previous methods in terms of accuracy.
  Information Processing Society of Japan, English, Scientific journal
  DOI：https://doi.org/10.2197/ipsjjip.17.180
  DOI ID：10.2197/ipsjjip.17.180, ISSN：1882-6652, DBLP ID：journals/jip/ShinyaSDIN09, SCOPUS ID：79951709044
• GPU-based rendering of point-sampled water surfaces　　　　　　　　　　　　　　　
  Kei Iwasaki; Yoshinori Dobashi; Fujiichi Yoshimoto; Tomoyuki Nishita
  VISUAL COMPUTER, Volume：24, Number：2, First page：77, Last page：84, Feb. 2008, [Reviewed]
  Particle-based simulations are widely used to simulate fluids. We present a real-time rendering method for the results of particle-based simulations of water. Traditional approaches to visualize the results of particle-based simulations construct water surfaces that are usually represented by polygons. To construct water surfaces from the results of particle-based simulations, a density function is assigned to each particle and a density field is computed by accumulating the values of the density functions of all particles. However, the computation of the density field is time consuming. To address this problem, we propose an efficient calculation of density field using a graphics processing unit (GPU). We present a rendering method for water surfaces sampled by points. The use of the GPU permits efficient simulation of optical effects, such as refraction, reflection, and caustics.
  SPRINGER, English, Scientific journal
  DOI：https://doi.org/10.1007/s00371-007-0186-8
  DOI ID：10.1007/s00371-007-0186-8, ISSN：0178-2789, eISSN：1432-2315, DBLP ID：journals/vc/IwasakiDYN08, Web of Science ID：WOS:000252486200001
• Global illumination using precomputed light paths for interactive light condition manipulation　　　　　　　　　　　　　　　
  Yonghao Yue; Kei Iwasaki; Yoshinori Dobashi; Tomoyuki Nishita
  ACM SIGGRAPH 2007 Sketches, SIGGRAPH'07, 2007, [Reviewed]
  English, International conference proceedings
  DOI：https://doi.org/10.1145/1278780.1278850
  DOI ID：10.1145/1278780.1278850, SCOPUS ID：64249151104
• Precomputed Radiance Transfer for Dynamic Scenes Taking into Account Light Interreflection.　　　　　　　　　　　　　　　
  Kei Iwasaki; Yoshinori Dobashi; Fujiichi Yoshimoto; Tomoyuki Nishita
  Proceedings of the Eurographics Symposium on Rendering Techniques, Grenoble, France, 2007, First page：35, Last page：44, 2007, [Reviewed]
  Eurographics Association
  DOI：https://doi.org/10.2312/EGWR/EGSR07/035-044
  DOI ID：10.2312/EGWR/EGSR07/035-044, DBLP ID：conf/rt/IwasakiDYN07
• Global illumination for interactive lighting design using light path pre-computation and hierarchical histogram estimation　　　　　　　　　　　　　　　
  Yonghao Yue; Kei Iwasaki; Yoshinori Dobashi; Tornoyuki Nishita
  PACIFIC GRAPHICS 2007: 15TH PACIFIC CONFERENCE ON COMPUTER GRAPHICS AND APPLICATIONS, First page：87, Last page：+, 2007, [Reviewed]
  In this paper we propose a fast global illumination solution for interactive lighting design. Using our method, light sources and the viewpoint are movable, and the characteristics of materials can be modified (assuming low-frequency BRDF) during rendering. Our solution is based on particle tracing (a variation of photon mapping) and final gathering. We assume that objects in the input scene are static, and pre-compute potential light paths for particle tracing and final gathering. To perfom final gathering fast, we propose an efficient technique called Hierarchical Histogram Estimation for rapid estimation of radiances from the distribution of the particles. The rendering process of our method can be fully implemented on the GPU and our method achieves interactive frame rates for rendering scenes with even more than 100, 000 triangles.
  IEEE, English, International conference proceedings
  DOI：https://doi.org/10.1109/PG.2007.60
  DOI ID：10.1109/PG.2007.60, DBLP ID：conf/pg/YueIDN07, Web of Science ID：WOS:000252141200013
• Precomputed radiance transfer for dynamic scenes with diffuse interreflection　　　　　　　　　　　　　　　
  Kei Iwasaki; Yoshinori Dobashi; Naoki Tamura; Henry Johan; Fujiichi Yoshimoto; Tomoyuki Nishita
  ACM SIGGRAPH 2006: Sketches, SIGGRAPH '06, 2006, [Reviewed]
  English, International conference proceedings
  DOI：https://doi.org/10.1145/1179849.1180065
  DOI ID：10.1145/1179849.1180065, SCOPUS ID：77951517735
• Real-time rendering of point based water surfaces　　　　　　　　　　　　　　　
  Kei Iwasaki; Yoshinori Dobashi; Fujiichi Yoshimotol; Tomoyuki Nishita
  ADVANCES IN COMPUTER GRAPHICS, PROCEEDINGS, Volume：4035, First page：102, Last page：114, 2006, [Reviewed]
  In recent years, attention has been paid to particle-based fluid simulation, with several methods being developed to incorporate particle-based simulation into CG animations. These methods reconstruct water surfaces that are usually represented by polygons. However, the computational cost of the surface reconstruction is quite high. Therefore, it is difficult to render the result of the particle-based simulation at interactive frame rates. To address this, we present a real-time method for rendering water surfaces resulting from particle-based simulation. We present an efficient GPU accelerated surface reconstruction method from particles, sampling the water surface point by point. In addition to rendering the point based water surfaces, the use of the GPU permits efficient simulation of optical effects such as refraction, reflection, and caustics.
  SPRINGER-VERLAG BERLIN, English, Scientific journal
  DOI：https://doi.org/10.1007/11784203_9
  DOI ID：10.1007/11784203_9, ISSN：0302-9743, DBLP ID：conf/cgi/IwasakiDYN06, Web of Science ID：WOS:000239486600009
• A method for fast rendering of caustics from refraction by transparent objects　　　　　　　　　　　　　　　
  K Iwasaki; F Yoshimoto; Y Dobashi; T Nishita
  IEICE TRANSACTIONS ON INFORMATION AND SYSTEMS, Volume：E88D, Number：5, First page：904, Last page：911, May 2005, [Reviewed]
  Caustics are patterns of light focused by reflective or refractive objects. Because of their visually fascinating patterns, several methods have been developed to render caustics. We propose a method for the quick rendering of caustics formed by refracted and converged light through transparent objects. First, in the preprocess, we calculate sampling rays incident on each vertex of the object, and trace the rays until they leave the object taking refraction into account. The position and direction of each ray that finally transmits the transparent object are obtained and stored in a lookup table. Next, in the rendering process, when the object is illuminated, the positions and directions of the rays leaving the object are calculated using the lookup table. This makes it possible to render refractive caustics due to transparent objects at interactive frame rates, allowing us to change the light position and direction, and translate and rotate the object.
  IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, English, Scientific journal
  DOI ID：10.1093/ietisy/e88-d.5.904, ISSN：1745-1361, DBLP ID：journals/ieicet/IwasakiYDN05, CiNii Articles ID：110003214263, Web of Science ID：WOS:000229253200017
• InCom: Support system for informal communication in 3D virtual worlds generated from HTML documents　　　　　　　　　　　　　　　
  Yuusuke Nakano; Koji Tsukada; Saeko Takagi; Kei Iwasaki; Fujiichi Yoshimoto
  IEICE Transactions on Information and Systems, Volume：E88-D, Number：5, First page：872, Last page：879, 2005, [Reviewed]
  The importance of informal communication on the Internet has been increasing in recent years. Several systems for informal communication have been developed. These systems, however, require a particular server and/or specialized 3D contents. In this paper, we propose a system, named InCom, for informal communication in a 3D virtual environment. Browsers which are component of InCom generate 3D virtual worlds from existing common 2D HTML documents. Browsers communicate in a peer-to-peer manner. Using avatars makes gaze awareness smooth. Our results show that users shared interests by gaze awareness. Copyright © 2005 The Institute of Electronics Information and Communication Engineers.
  Institute of Electronics, Information and Communication, Engineers, IEICE, English, International conference proceedings
  DOI：https://doi.org/10.1093/ietisy/e88-d.5.872
  DOI ID：10.1093/ietisy/e88-d.5.872, ISSN：0916-8532, SCOPUS ID：24144471888
• A method for fast rendering of caustics from refraction by transparent objects　　　　　　　　　　　　　　　
  Kei Iwasaki; Fujiichi Yoshimoto; Yoshinori Dobashi; Tomoyuki Nishita
  IEICE Transactions on Information and Systems, Volume：E88-D, Number：5, First page：904, Last page：910, 2005, [Reviewed]
  Caustics are patterns of light focused by reflective or refractive objects. Because of their visually fascinating patterns, several methods have been developed to render caustics. We propose a method for the quick rendering of caustics formed by refracted and converged light through transparent objects. First, in the preprocess, we calculate sampling rays incident on each vertex of the object, and trace the rays until they leave the object taking refraction into account. The position and direction of each ray that finally transmits the transparent object are obtained and stored in a lookup table. Next, in the rendering process, when the object is illuminated, the positions and directions of the rays leaving the object are calculated using the lookup table. This makes it possible to render refractive caustics due to transparent objects at interactive frame rates, allowing us to change the light position and direction, and translate and rotate the object. Copyright © 2005 The Institute of Electronics, Information and Communication Engineers.
  Institute of Electronics, Information and Communication, Engineers, IEICE, English, International conference proceedings
  DOI：https://doi.org/10.1093/ietisy/e88-d.5.904
  DOI ID：10.1093/ietisy/e88-d.5.904, ISSN：0916-8532, SCOPUS ID：24144442750
• Support system for informal communication in 3D web world　　　　　　　　　　　　　　　
  Yuusuke Nakano; Koji Tsukada; Saeko Takagi; Kei Iwasaki; Fujiichi Yoshimoto
  Proceedings - 2004 International Conference on Cyberworlds, CW 2004, First page：439, Last page：446, 2004, [Reviewed]
  The importance of informal communication on the Internet has been increasing in recent years. Several systems for informal communication are currently available to the public. These systems, however, require a particular server and/or specialized 3D content. In this paper, we propose a system for informal communication in a 3D virtual environment. The system makes 3D virtual worlds from existing common 2D HTML documents. Browsers communicate in a peer-to-peer manner. Construction and management of the system can be achieved with ease and at low cost in contrast with existing 3D virtual communication systems. Our results show that users shared interests by gaze awareness. © 2004 IEEE.
  English, International conference proceedings
  DOI：https://doi.org/10.1109/CW.2004.58
  DOI ID：10.1109/CW.2004.58, SCOPUS ID：19544394400
• Real-time rendering of soap bubbles taking into account light interference　　　　　　　　　　　　　　　
  Kei Iwasaki; Keichi Matsuzawa; Tomoyuki Nishita
  Proceedings of Computer Graphics International Conference, CGI, First page：344, Last page：348, 2004, [Reviewed]
  In the field of computer graphics, simulation of physical phenomena is of great interest. We focus on the optical effects of soap bubbles. Soap bubbles have fascinating coloration and interesting physical properties. Therefore they are useful for the entertainment such as movies and games. Soap bubbles change their shapes by surface tension and external forces, and therefore their surface thickness also changes. Since the thickness of the soap bubble is several hundred nanometers, interference of the light occurs. This paper proposes a fast rendering method for the soap bubbles taking into account light interference and dynamics. In our method, the reflectivities of the thin film that is the cause of the light interference are calculated in advance and stored as textures. This makes it possible to render the deformable soap bubbles in real-time.
  English, International conference proceedings
  DOI：https://doi.org/10.1109/CGI.2004.1309231
  DOI ID：10.1109/CGI.2004.1309231, ISSN：1530-1052, SCOPUS ID：5444237537
• A rapid rendering method for caustics arising from refraction by transparent objects　　　　　　　　　　　　　　　
  K Iwasaki; F Yoshimoto; Y Dobashi; T Nishita
  2004 INTERNATIONAL CONFERENCE ON CYBERWORLDS, PROCEEDINGS, First page：39, Last page：44, 2004, [Reviewed]
  Caustics are patterns of light formed by reflection or refraction of light from objects, and several methods have been developed to render caustics because of their visually beautiful patterns. This paper proposes a method for the rapid rendering of caustics formed by refracted light through transparent objects. First, a preprocess is used to generate sampling rays incident on each vertex of the object, and, taking refraction into account, to trace the rays until they leave the object. The position and direction of each ray that finally leaves the transparent object are obtained and stored in a lookup table. Next, in the rendering process, when the object is illuminated, the position and direction of the rays leaving the object are calculated using the lookup table. This makes it possible to render refractive caustics due to transparent objects at interactive frame rates even if the direction of the light changes and the object is translated or rotated.
  IEEE COMPUTER SOC, English, International conference proceedings
  DOI：https://doi.org/10.1109/CW.2004.12
  DOI ID：10.1109/CW.2004.12, DBLP ID：conf/cw/IwasakiYND04, Web of Science ID：WOS:000225591700005
• A volume rendering approach for sea surfaces taking into account second order scattering using scattering maps　　　　　　　　　　　　　　　
  Kei Iwasaki; Yoshinori Dobashi; Tomoyuki Nishita
  ACM International Conference Proceeding Series, Volume：45, First page：129, Last page：171, 2003, [Reviewed]
  We present a fast volume rendering technique for sea surfaces taking into account second order scattering using graphics hardware. To generate realistic images of the sea surfaces, accurate simulation of light transport within water is necessary. In particular, multiple scattering due to particles in the water plays an important role in creating realistic images. In this paper, we introduce the concept of a scattering map for efficient computation of light scattering within water volume. In order to calculate second order scattering of light, we slice the water volume into virtual horizontal planes and calculate the radiance from second order scattering of light at sampling points on these planes. The radiance on the virtual planes can be treated as a texture map. This makes it possible to accelerate the computation using graphics hardware. © The Eurographics Association 2003.
  Eurographics Association, English, International conference proceedings
  DOI：https://doi.org/10.1145/827051.827071
  DOI ID：10.1145/827051.827071, DBLP ID：conf/vg/IwasakiDN03, SCOPUS ID：77953775728
• A fast rendering method for refractive and reflective caustics due to water surfaces　　　　　　　　　　　　　　　
  K Iwasaki; Y Dobashi; T Nishita
  Computer Graphics Forum, Volume：22, Number：3, First page：601, Last page：609, 2003, [Reviewed]
  In order to synthesize realistic images of scenes that include water surfaces, the rendering of optical affects caused by waves on the water surface, such as caustics and reflection, is necessary. However, rendering caustics is quite complex and time-consuming. In recent years, the performance of graphics hardware has made significant progress. This fact encourages researchers to study the acceleration of realistic image synthesis. We present here a method for the fast rendering of refractive and reflective caustics due to water surfaces. In the proposed method, an object is expressed by a set of texture mapped slices. We calculate the intensities of the caustics on the object by using the slices and store the intensities as textures. This makes it possible to render caustics at interactive rate by using graphics hardware. Moreover, we render objects that are reflected and refracted due to the water surface by using reflection/refraction mapping of these slices.
  WILEY-BLACKWELL, English, Scientific journal
  DOI：https://doi.org/10.1111/1467-8659.t01-2-00708
  DOI ID：10.1111/1467-8659.t01-2-00708, ISSN：0167-7055, eISSN：1467-8659, DBLP ID：journals/cgf/IwasakiDN03, Web of Science ID：WOS:000185322200044
• An efficient method for rendering underwater optical effects using graphics hardware　　　　　　　　　　　　　　　
  Kei Iwasaki; Yoshinori Dobashi; Tomoyuki Nishita
  Computer Graphics Forum, Volume：21, Number：4, First page：701, Last page：711, 2002, [Reviewed]
  The display of realistic natural scenes is one of the most important research areas in computer graphics. The rendering of water is one of the essential components. This paper proposes an efficient method for rendering images of scenes within water. For underwater scenery, the shafts of light and caustics are attractive and important elements. However, computing these effects is difficult and time-consuming since light refracts when passing through waves. To address the problem, our method makes use of graphics hardware to accelerate the computation. Our method displays the shafts of light by accumulating the intensities of streaks of light by using hardware color blending functions. Making use of a Z-buffer and a stencil buffer accelerates the rendering of caustics. Moreover, by using a shadow mapping technique, our method can display shafts of light and caustics taking account of shadows due to objects.
  Blackwell Publishing Ltd., English, International conference proceedings
  DOI：https://doi.org/10.1111/1467-8659.00628
  DOI ID：10.1111/1467-8659.00628, ISSN：0167-7055, SCOPUS ID：0036919724
• Efficient rendering of optical effects within water using graphics hardware　　　　　　　　　　　　　　　
  K Iwasaki; Y Dobashi; T Nishita
  NINTH PACIFIC CONFERENCE ON COMPUTER GRAPHICS AND APPLICATIONS, PROCEEDINGS, First page：374, Last page：383, 2001, [Reviewed]
  The display of realistic natural scenes is one of the most important research areas in computer graphics. The rendering of water is one of the essential components. This paper proposes an efficient method for rendering images of scenes within water For underwater scenery, the shafts of light and caustics are attractive and important elements. However computing these effects is difficult and time-consuming since light refracts when passing through waves. To address the problem, our method makes use of graphics hardware to accelerate the computation. Our method displays the shafts of light by accumulating the intensities of streaks of light by using hardware color blending functions. The rendering of caustics is accelerated by making use of a Z-buffer and a stencil buffer. Moreover, by using a shadow mapping technique, our method can display shafts of light and caustics taking account of shadows due to objects.
  IEEE COMPUTER SOC, English, International conference proceedings
  DOI：https://doi.org/10.1109/PCCGA.2001.962894
  DOI ID：10.1109/PCCGA.2001.962894, DBLP ID：conf/pg/IwasakiND01, Web of Science ID：WOS:000172028900042

• 3D Gaussian Splattingにおける透明材質への編集手法　　　　　　　　　　　　　　　
  鏑木嘉人; 岩崎 慶
  Mar. 2025, [Last]
  Summary national conference
• 糸手続き型モデルを用いたSGGXパラメータの推定　　　　　　　　　　　　　　　
  松田理沙; 岩崎 慶
  Mar. 2025, [Last]
  Japanese, Summary national conference
• 2種類の基底を用いた複数画像を入力とするSVBRDF予測モデルの提案　　　　　　　　　　　　　　　
  小築知弥; 岩崎 慶
  Mar. 2025, [Last]
  Summary national conference
• 球面調和関数を用いた環境マップ下における織物の糸レベルレンダリング　　　　　　　　　　　　　　　
  奥野 健一郎; 岩崎 慶
  Mar. 2024, [Last]
  Summary national conference
• ニューラル基底関数の精度向上に関する検討　　　　　　　　　　　　　　　
  中 滉季; 岩崎 慶
  Mar. 2024
  Summary national conference
• 異方性フィルタを用いたテクスチャ光源のシェーディング　　　　　　　　　　　　　　　
  高尾 秀太; 岩崎 慶
  Sep. 2023
  Summary national conference
• 異方性計測スペクトラルBRDFのノンパラメトリック表現　　　　　　　　　　　　　　　
  岩崎 慶
  Jun. 2023, [Lead, Last, Corresponding]
  Summary national conference
• 帯域調和関数分解を用いた球光源の球面調和係数の解析的勾配計算　　　　　　　　　　　　　　　
  萬谷 響; 岩崎 慶
  Jun. 2023, [Last]
  Summary national conference
• 2次元のBRDF分布の補間による金属表面上の傷のデザインシステム　　　　　　　　　　　　　　　
  藤真太郎; 佐藤周平; 岩崎慶; 土橋宜典
  Volume：2023, Number：CG-191, 2023
  J-Global ID：202302259574958647
• 板状透明物体のための屈折を考慮したモーションベクトルの一検　　　　　　　　　　　　　　　
  山下大智; 岩崎慶
  Oct. 2022, [Last]
  Summary national conference
• 計測スペクトラルBRDFの解析モデル近似　　　　　　　　　　　　　　　
  佐藤 眞宏; 岩崎 慶
  Sep. 2022, [Last]
  Summary national conference
• 微分可能レンダリングによるガウシアンフィルタリングのパラメータ推定　　　　　　　　　　　　　　　
  北林 悠河; 岩崎 慶
  Jun. 2022, [Last]
  Summary national conference
• 微分可能レンダリングを用いた髪の毛・毛皮の散乱パラメータ推定　　　　　　　　　　　　　　　
  芝池 祐星; 岩崎 慶
  First page：1, Last page：2, Mar. 2022, [Last, Corresponding]
  Summary national conference
• 計測BRDFを考慮した多角形光源のレンダリング　　　　　　　　　　　　　　　
  田中 剣樹; 岩崎 慶
  First page：1, Last page：2, Mar. 2022, [Last, Corresponding]
  Summary national conference
• SV-BRDFを用いた透明物体表面上の傷のレンダリング　　　　　　　　　　　　　　　
  藤 真太郎; 佐藤 周平; 岩崎 慶
  Volume：2021, Number：CG-184, Nov. 2021
  Summary national conference
  J-Global ID：202102241518117860
• SV-BRDFを用いた傷のある透明物体のレンダリング　　　　　　　　　　　　　　　
  藤 真太郎; 佐藤 周平; 岩崎 慶; 高 尚策; 唐 政
  Sep. 2021
  Summary national conference
• 表面凹凸を考慮した光沢反射のためのモーションベクトルに関する一検討　　　　　　　　　　　　　　　
  藤田 龍也; 岩崎 慶
  Sep. 2021, [Last, Corresponding]
  Japanese, Summary national conference
• DeepBRDFによる計測スペクトラルBRDFの圧縮の検討　　　　　　　　　　　　　　　
  岡田 実生; 岩崎 慶
  Sep. 2021, [Last, Corresponding]
  Summary national conference
• 計測スペクトラルBRDFの成分分離による編集　　　　　　　　　　　　　　　
  引地 将大; 岩崎 慶
  First page：1, Last page：6, Sep. 2021, [Reviewed], [Last, Corresponding]
  Summary national conference
• スペクトルを考慮した計測BRDFの圧縮表現　　　　　　　　　　　　　　　
  大西和輝; 岩崎慶
  First page：1, Last page：1, Mar. 2021, [Last, Corresponding]
  Summary national conference
• 多重散乱を考慮したCook-TorranceBRDFの球面調和関数近似　　　　　　　　　　　　　　　
  今入一博; 岩崎慶
  First page：1, Last page：1, Mar. 2021, [Last]
  Summary national conference
• Micro-specular-highlight real-time rendering　　　　　　　　　　　　　　　
  N. Podee; N. Max; K. Iwasaki; Y. Dobashi
  Feb. 2021
  Summary national conference
• Realistic Appearance Representation Using Computer Graphics　　　　　　　　　　　　　　　
  岩崎慶
  光学, Volume：50, Number：8, 2021, [Invited]
  Report scientific journal
  ISSN：0389-6625, J-Global ID：202102282174067059
• 毛のレンダリングのための効率的な重点的サンプリング　　　　　　　　　　　　　　　
  芝池 祐星; 岩崎 慶
  Dec. 2020, [Reviewed], [Last, Corresponding]
  Japanese, Summary national conference
• クラスタリングを用いたニューラルBTFの圧縮
  岡田 実生; 岩崎 慶
  Number：2020, 11 Sep. 2020, [Last, Corresponding]
  Japanese, Summary national conference
  ISSN：1884-197X, CiNii Articles ID：170000183749
• 髪の毛・毛皮のための効率的な重点的サンプリング
  芝池 祐星; 岩崎 慶
  Number：2020, 11 Sep. 2020, [Last, Corresponding]
  Japanese, Summary national conference
  ISSN：1884-197X, CiNii Articles ID：170000183750
• ガウス過程を用いたスペクトラルBRDFの予測
  引地 将大; 岩崎 慶
  Number：2020, 11 Sep. 2020, [Last, Corresponding]
  Japanese, Summary national conference
  ISSN：1884-197X, CiNii Articles ID：170000183751
• Adaptive Super Sampling for Rendering Reflections on Water Surfaces　　　　　　　　　　　　　　　
  N. Podee; N. Max; K. Iwasaki; Y. Dobashi
  Jun. 2020
  English, Summary national conference
• バイナリ空間分割木を用いた多角形光源による影の計算　　　　　　　　　　　　　　　
  奥野弘貴; 岩崎慶
  情報処理学会研究報告(Web), Volume：2019, Number：DCC-23, First page：Vol.2019‐DCC‐23,No.8,1‐6 (WEB ONLY), 31 Oct. 2019, [Last, Corresponding]
  Japanese, Summary national conference
  J-Global ID：201902288722657015
• Latest Trends in Computer Graphics Research　　　　　　　　　　　　　　　
  岩崎慶
  映像情報メディア学会技術報告, Volume：43, Number：17(BCT2019 48-57), First page：17‐18, 07 Jun. 2019, [Invited], [Last, Corresponding]
  Japanese, Summary national conference
  ISSN：1342-6893, J-Global ID：201902262439026297
• Circular Gaussian anti-aliasing for rendering reflection on water surface　　　　　　　　　　　　　　　
  N. Podee; N. Max; K. Iwasaki; Y. Dobashi
  Jun. 2019
  English, Summary national conference
• 幾何減衰項の異方性を考慮したBRDFの因子分解,　　　　　　　　　　　　　　　
  明石佳祐; 岩崎慶
  Mar. 2019, [Last]
  Summary national conference
• 光沢反射を考慮した多光源レンダリングのための誤差推定法　　　　　　　　　　　　　　　
  岩崎 陸人; 名畑 豪祐; 酒井 広和; 岩崎 慶
  Volume：2019, Number：1, First page：527, Last page：528, 28 Feb. 2019, [Last, Corresponding]
  大域照明の効率的なレンダリングをするための手法に仮想的な点光源（Virtual Point Light:VPL）を用いる多光源レンダリング法がある．先行研究ではVPLとシェーディング点をそれぞれクラスタリングし，真値との相対誤差を確率的に推定することで効率的なレンダリングを実現した．しかしながら，先行研究では拡散反射のような反射率が一定の反射モデルしか考慮されていない．そこで，提案法では先行研究を拡張し，物体表面の材質として光沢反射を考慮して，真値との相対誤差を確率的に推定する手法を提案する．提案法ではキューブマップを用いて各方向の反射率を記録しておくことで．クラスタ内の分散の計算を効率的に行えるようにした．
  Japanese, Summary national conference
  CiNii Articles ID：170000179778, CiNii Books ID：AN00349328
• スーパーサンプリングを用いた多光源レンダリングのための誤差推定法　　　　　　　　　　　　　　　
  酒井広和; 名畑豪祐; 安明真哉; 岩崎慶
  Jun. 2018, [Reviewed], [Last, Corresponding]
  Japanese, Summary national conference
• 微細構造における相互反射を考慮したバラのBRDFモデル　　　　　　　　　　　　　　　
  元辻香苗; 名畑豪祐; 岩崎慶
  Meeting of Federation of Imaging Societies (CD-ROM), Volume：5th, First page：ROMBUNNO.3A09, 2018, [Last, Corresponding]
  Japanese, Summary national conference
  J-Global ID：201902262778712225
• 布のCG表現のための見た目のモデリング　　　　　　　　　　　　　　　
  土橋宜典; 土橋宜典; 岩崎慶; 岡部誠; 井尻敬; 藤堂英樹
  情報処理学会研究報告(Web), Volume：2017, Number：DCC-17, First page：Vol.2017‐DCC‐17,No.25,1‐5 (WEB ONLY), 01 Nov. 2017
  Japanese, Summary national conference
  J-Global ID：201702212431361228
• An Error Estimation Method for Rendering Participating Media　　　　　　　　　　　　　　　
  岩崎慶; 名畑豪祐
  情報処理学会研究報告(Web), Volume：2017, Number：DCC-17, First page：Vol.2017‐DCC‐17,No.8,1‐6 (WEB ONLY), 01 Nov. 2017, [Lead, Corresponding]
  Japanese, Summary national conference
  J-Global ID：201702238619146310
• 線形変換された余弦分布を用いた効率的な相互反射計算　　　　　　　　　　　　　　　
  岡田航輔; 岩崎慶
  情報処理学会関西支部支部大会講演論文集(CD-ROM), Volume：2017, First page：ROMBUNNO.G‐23, 15 Sep. 2017, [Last, Corresponding]
  Japanese, Summary national conference
  ISSN：1884-197X, J-Global ID：201702235869627232
• マルチグリッド法のためのNサイクルの提案　　　　　　　　　　　　　　　
  鶴賀淳樹; 岩崎慶; 岩崎慶
  Visual Computing/グラフィクスとCAD合同シンポジウム予稿集(CD-ROM), Volume：2017, First page：ROMBUNNO.39, 23 Jun. 2017, [Last, Corresponding]
  Japanese, Summary national conference
  J-Global ID：201702231374026358
• 領域削減の自動化によるWavelet Turbulenceの効率化　　　　　　　　　　　　　　　
  上西直人; 佐藤周平; 岩崎慶; 西田友是; 西田友是
  情報処理学会全国大会講演論文集, Volume：79th, Number：4, First page：4.63‐4.64, 16 Mar. 2017
  Japanese
  J-Global ID：201702246610069018
• 複数のfar‐field格子を用いた流体シミュレーション　　　　　　　　　　　　　　　
  大垣公輔; 佐藤周平; 岩崎慶; 西田友是; 西田友是
  情報処理学会全国大会講演論文集, Volume：79th, Number：4, First page：4.61‐4.62, 16 Mar. 2017
  Japanese
  J-Global ID：201702248735536203
• 関与媒質の多光源レンダリングのための誤差推定法　　　　　　　　　　　　　　　
  安明真哉; 名畑豪祐; 岩崎慶
  情報処理学会全国大会講演論文集, Volume：79th, Number：4, First page：4.123‐4.124, 16 Mar. 2017
  Japanese
  J-Global ID：201702285672418894
• “Physically‐Accurate Fur Reflectance:Modeling,Measurement and Rendering”の実装報告　　　　　　　　　　　　　　　
  柏木彰; 溝口智博; 岩崎慶
  情報処理学会研究報告(Web), Volume：2016, Number：CG-164, First page：Vol.2016‐CG‐164,No.7,1‐2 (WEB ONLY), 14 Sep. 2016
  Japanese
  J-Global ID：201702237668974978
• 複数画像を再現可能な反射板設計　　　　　　　　　　　　　　　
  櫻井快勢; YUE Yonghao; 金森由博; 岩崎慶; 岩崎慶; 土橋宜典; 土橋宜典; 西田友是; 西田友是
  Visual Computing/グラフィクスとCAD合同シンポジウム予稿集(CD-ROM), Volume：2016, First page：ROMBUNNO.04, 18 Jun. 2016
  Japanese
  J-Global ID：201602259168438160
• GPUを用いたFast Marching Methodの高速化の一手法　　　　　　　　　　　　　　　
  鶴賀淳樹; 岩崎慶
  情報処理学会全国大会講演論文集, Volume：78th, Number：4, First page：4.189-4.190, 10 Mar. 2016
  Japanese
  J-Global ID：201602218825524269
• マイクロストラクチャからのBRDFの推定　　　　　　　　　　　　　　　
  井尻敬; 岩崎慶; 岡部誠; 藤堂英樹; 土橋宜典; 西村智; PODEE Namo
  画像電子学会誌(CD-ROM), Volume：45, Number：1, First page：124‐125, 30 Jan. 2016
  Japanese
  ISSN：2186-716X, J-Global ID：201602219803342520
• A Survey on Fast Rendering Methods for Image‐based Lighting　　　　　　　　　　　　　　　
  岩崎慶
  画像電子学会誌(CD-ROM), Volume：44, Number：3, First page：408, Last page：415, 30 Jul. 2015
  Image-based lighting is widely used to represent real-world, complex lighting in recent years. Image-based lighting captures surrounding environment illumination as an environment map, and uses it for the illumination. Although realistic images can be rendered by using image-based lighting, the computational cost using image-based lighting can be prohibitive since rendering under image-based lighting requires the product integral of incident radiance, visibility function, BRDF over the hemisphere. This paper surveys the recent papers on fast rendering using image-based lighting.
  The Institute of Image Electronics Engineers of Japan, Japanese
  DOI：https://doi.org/10.11371/iieej.44.408
  DOI ID：10.11371/iieej.44.408, ISSN：2186-716X, J-Global ID：201502201943203089, CiNii Articles ID：130005171506, CiNii Books ID：AA12563298
• VPLサンプリングのための効率的な可視関数の確率的評価　　　　　　　　　　　　　　　
  名畑豪祐; 岩崎慶; 土橋宜典; 土橋宜典; 西田友是; 西田友是
  Visual Computing/グラフィクスとCAD合同シンポジウム予稿集(CD-ROM), Volume：2015, First page：ROMBUNNO.12, 27 Jun. 2015
  Japanese
  J-Global ID：201502208081054320
• ベクトルポテンシャルを用いた流体流れ場の編集　　　　　　　　　　　　　　　
  佐藤周平; 土橋宜典; 土橋宜典; 土橋宜典; YUE Yonghao; 岩崎慶; 岩崎慶; 西田友是; 西田友是
  Visual Computing/グラフィクスとCAD合同シンポジウム予稿集(CD-ROM), Volume：2015, First page：ROMBUNNO.11, 27 Jun. 2015
  Japanese
  J-Global ID：201502219020185459
• ベクトルポテンシャルを用いた非圧縮性流体流れ場の変形　　　　　　　　　　　　　　　
  佐藤 周平; 土橋 宜典; 楽 詠灝; 岩崎 慶; 西田 友是
  Volume：2015, Number：1, First page：57, Last page：58, 17 Mar. 2015
  近年，映画やゲームなどにおいて，流体シミュレーションを用いた映像制作が盛んに行われている．このような映像制作では，特にSFやファンタジー 映画において，物理シミュレーションを用いつつも，現実では起こりえないような流体の映像が求められる．このような場合，流体の流れ場を変形する ことで，そのような映像の容易な作成が期待できる．しかし，単純に流れ場を変形した場合，流体が満たすべき物理法則である質量保存，運動量保存を 満たすことができない．特に，質量保存が満たされない場合，意図しない場所から流体が湧き出るなど，視覚的に問題となる場合が多い．そこで本手法 では，2つの物理法則のうち質量保存，すなわち流体の非圧縮性を保った流れ場の変形を実現する．
  Japanese
  CiNii Articles ID：170000165239
• メトロポリス光輸送法における双方向変異法のための光路サンプリング戦略決定について　　　　　　　　　　　　　　　
  大津 久平; 楽 詠コウ; 侯 啓明; 岩崎 慶; 土橋 宜典; 須田 礼二; 西田 友是
  Volume：2015, Number：2, First page：1, Last page：7, 20 Feb. 2015
  写実的な画像を生成するための大域照明計算はコンピュータグラフィックスにおいて重要な分野である.近年,マルコフ連鎖モンテカルロ法を用いた大域照明計算法が活発に研究,開発されている.例えば,マルコフ連鎖モンテカルロ法 (MCMC) を用いるレンダリング手法の一つであるメトロポリス光輸送法 (MLT) はある規則に従って光路を変異させながら,光路空間におけるエネルギーの寄与分布に従うようなマルコフ連鎖を生成する.MCMC を用いるレンダリング手法では,サンプルが次元の境界を超える際に次元間変異が用いられる.例えば,MLT では次元間変異として双方向変異法を用い,光路の長さや構造を変異させる.このような次元間変異手法はしばしばサンプル過程のエルゴード性を保つために用いられ,いくつかの手法にとっては次元間変異は必須である.しかしながら MCMC を用いたレンダリングにおいて,次元間変異の効率を改善するための研究はほとんど試されてこなかった.そこで,本稿では,双方向変異法の効率の改良について考察する.重点的サンプリングに類似した考え方に基づく双方向変異法の効率についての解析から,光路サンプリング戦略の決定を行う分布の制御によって,双方向変異法の採択確率を向上できることが分かる.この解析に基づき,我々は焼きなまし法を用いて採択確率の期待値を最大化することで光路サンプリング戦略の決定分布を効率化する手法を提案する.この手法を用いることにより,双方向変異法の特徴を残しながら高い遷移確率で光路をサンプリングすることができる.
  Japanese
  CiNii Articles ID：110009877776, CiNii Books ID：AN10100541
• キャッシュ点を用いた関与媒質の多光源レンダリング　　　　　　　　　　　　　　　
  榎谷亮祐; 岩崎慶
  Meeting of Federation of Imaging Societies (CD-ROM), Volume：2nd, First page：ROMBUNNO.B03, 2015
  Japanese
  J-Global ID：201602213284599854
• 写真を用いた雲のモデリング　　　　　　　　　　　　　　　
  岩崎慶; 土橋宜典; 岡部誠; 山本強
  Meeting of Federation of Imaging Societies (CD-ROM), Volume：2nd, First page：ROMBUNNO.PC10, 2015
  Japanese
  J-Global ID：201602213386381446
• イメージベーストライティングの基礎から最新技術まで　　　　　　　　　　　　　　　
  岩崎慶
  画像電子学会秋期セミナー予稿, Volume：37th, First page：20‐36, 2015
  Japanese
  J-Global ID：201602214508531696
• 間接光を考慮したピクセルアートのシェーディング手法　　　　　　　　　　　　　　　
  仲北和弘; 岩崎慶
  Meeting of Federation of Imaging Societies (CD-ROM), Volume：2nd, First page：ROMBUNNO.B04, 2015
  Japanese
  J-Global ID：201602216526424352
• 高解像度法線マップを用いたハイライトの効率的レンダリング　　　　　　　　　　　　　　　
  溝口智博; 名畑豪祐; 岩崎慶
  Meeting of Federation of Imaging Societies (CD-ROM), Volume：2nd, First page：ROMBUNNO.B02, 2015
  Japanese
  J-Global ID：201602221126189056
• An Acceleration Method for Divide-And-Conquer Ray Tracing Using Ray Sampling　　　　　　　　　　　　　　　
  名畑 豪祐; 岩崎 慶; 土橋 宜典; 西田 友是
  IPSJ Journal, Volume：55, Number：12, First page：2559, Last page：2568, 15 Dec. 2014
  In this paper, we propose an efficient ray tracing method based on divide-and-conquer approach. Previous divide-and-conquer ray tracing (DACRT) methods subdivide intersection problems between large numbers of rays and primitives, by recursively subdividing the problem size based on the distribution of primitives only, until it can be easily solved. To subdivide the intersection problems, the lack of considering the distribution of rays can decrease the rendering performance, especially for high resolution images with antialiasing. To address this problem, our method exploits the distribution of rays for subdivision of intersection problems, construction of acceleration data structure, and determination of ray traversal order. To accelerate ray traversals, we have derived a new cost metric which is used to avoid inefficient subdivision of the intersection problem where the number of rays is not sufficiently reduced at the cost of expensive intersection tests between rays and bounding volumes. The cost metric is easy to calculate and hence easy to implement. Our method can accelerate the tracing of many types of rays by a factor of up to two. In addition, we show that our method can reduce the number of intersection tests between rays and bounding volumes compared to the state-of-the-art DACRT method.
  Information Processing Society of Japan (IPSJ), Japanese
  ISSN：1882-7764, CiNii Articles ID：110009851542, CiNii Books ID：AN00116647
• Poisson-Based Continuous Surface Generation for Goal-Based Caustics　　　　　　　　　　　　　　　
  Yonghao Yue; Kei Iwasaki; Bing-yu Chen; Yoshinori Dobashi; Tomoyuki Nishita
  IPSJ SIG Notes, Volume：2014, Number：1, First page：1, Last page：1, 09 Sep. 2014
  We present a technique for computing the shape of a transparent object that can generate user-defined caustic patterns. The surface of the object generated using our method is smooth. Thanks to this property, the resulting caustic pattern is smooth, natural, and highly detailed compared to the results obtained using previous methods. Our method consists of two processes. First, we use a differential geometry approach to compute a smooth mapping between the distributions of the incident light and the light reaching the screen. Second, we utilize this mapping to compute the surface of the object. We solve Poisson's equation to compute both the mapping and the surface of the object.
  Information Processing Society of Japan (IPSJ), Japanese
  CiNii Articles ID：110009821884, CiNii Books ID：AN10100541
• ラプラシアン固有関数を用いた流体の流れ場のインタラクティブなデザイン手法　　　　　　　　　　　　　　　
  佐藤周平; 土橋宜典; 岩崎慶; 落合啓之; 山本強
  電子情報通信学会論文誌 D(Web), Volume：J97-D, Number：9, First page：1528-1536 (WEB ONLY), 01 Sep. 2014
  Japanese
  ISSN：1881-0225, J-Global ID：201402259160467091
• 多光源レンダリング法のための効率的な可視関数の確率的評価　　　　　　　　　　　　　　　
  名畑豪祐; 岩崎慶; 土橋宜典; 西田友是
  Visual Computing/グラフィクスとCAD合同シンポジウム予稿集(CD-ROM), Volume：2014, First page：ROMBUNNO.13, 29 Jun. 2014
  Japanese
  J-Global ID：201402276694522421
• Generating Flow Fields Variations using Laplacian Eigenfunctions　　　　　　　　　　　　　　　
  Syuhei Sato; Yoshinori Dobashi; Kei Iwasaki; Hiroyuki Ochiai; Tsuyoshi Yamamoto
  Mathematical Progress in Expressive Image Synthesis Ⅰ, First page：93, Last page：101, Jun. 2014, [Reviewed]
  English, Lecture materials
• クラスタ主成分分析による符号付き球面距離関数の圧縮　　　　　　　　　　　　　　　
  川口貴大; 岩崎慶
  Volume：2014, Number：1, First page：305, Last page：306, 11 Mar. 2014
  近年，コンピュータグラフィックスの分野では，イメージベースライティング(IBL)を用いた照明計算手法が数多く提案されている．IBLによる照明計算は，高品質な画像が生成できる一方，処理が高コストという欠点がある．この問題を解決するために，WangらはIBLを考慮した物体表面の放射輝度を高速に計算する手法として符号付球面距離関数(Spherical Signed Distance Function，以下SSDFと略す)を提案した．Wangらは各頂点でSSDFを計算し，主成分分析により圧縮をしているが，この手法では頂点数の多いオブジェクトを扱うことが難しい．そこで，本研究では物体表面の頂点をクラスタリングし，クラスタ主成分分析を用いて符号付き球面距離関数を圧縮する手法を提案する．
  Japanese
  CiNii Articles ID：170000087037, CiNii Books ID：AN00349328
• 氷結による亀裂のビジュアルシミュレーション　　　　　　　　　　　　　　　
  八木貴志; 岩崎慶
  Volume：2014, Number：1, First page：349, Last page：350, 11 Mar. 2014
  氷のビジュアルシミュレーションは，自然現象を表現するコンピュータグラフィックスの分野の中でも重要な研究の1つである．これまでに氷結シミュレーションに関する研究は多く行われてきたが，氷結時に発生する亀裂を考慮した研究は行われていない．氷結による亀裂は，水から氷に変化する際の体積膨張や，容器と氷の間に発生する反発力・摩擦力などによって，氷内部にひずみが蓄積するために発生する．そこで本研究ではこのような氷結時に見られる現象を考慮した破壊シミュレーションを行い，氷中に亀裂を生成する手法を提案する．
  Japanese
  CiNii Articles ID：170000087058, CiNii Books ID：AN00349328
• SUREを用いた適応的サンプリングの高速化　　　　　　　　　　　　　　　
  榎谷亮祐; 岩崎慶
  Volume：2014, Number：1, First page：303, Last page：304, 11 Mar. 2014
  本研究はモンテカルロレンダリングにおけるノイズを削減する手法の1つであるSURE(Stein's unbiased risk Estimate)を用いた誤差推定によるフィルタリングの高速化手法を提案する。写実的な画像生成法の1つにモンテカルロレンダリング手法があげられる が、ノイズの少ない高品質な画像生成には計算時間がかかるという問題がある。近年少ないサンプルでモンテカルロレンダリングを行いフィルタリング によりノイズを削減する手法が提案されており、SUREを用いた手法はその1つである。SUREを用いると少ないサンプルでノイズが少ない画像を生成できるがそれでもまだ計算コストが高い。そこで本研究はGPUを用いて並列処理することでSUREベースのフィルタリング処理を高速化する。
  Japanese
  CiNii Articles ID：170000087036, CiNii Books ID：AN00349328
• 非等方性球面ガウス関数を用いた環境マップの近似手法　　　　　　　　　　　　　　　
  仲北和弘; 岩崎慶
  Volume：2014, Number：1, First page：307, Last page：308, 11 Mar. 2014
  環境マップで表される環境照明を用いることで，写実的なレンダリングを行うImage-based Lighting手法が着目されているが，計算コストが高いという問題がある．この問題を解決するために，環境マップを少数の非等方性球面ガウス関数(Anisotropic Spherical Gaussian, 以降ASGと略す)で近似することによって高速なレンダリングを実現する手法が提案されている．環境マップを近似するASGを求めるためには，非線形最適化問題を解く必要がある．非線形最適化問題では，初期値の選び方が重要であるが，先行研究では初期値の計算方法について提案されていない．そこで本研究では，環境マップの輝度が高い領域をASGに対応した楕円形状で近似することにより，効率的な初期値の計算方法を提案する．
  Japanese
  CiNii Articles ID：170000087038, CiNii Books ID：AN00349328
• SUREを用いた適応的サンプリングの高速化　　　　　　　　　　　　　　　
  榎谷亮祐; 岩崎慶
  情報処理学会全国大会講演論文集, Volume：76th, Number：4, First page：4.303-4.304, 11 Mar. 2014
  Japanese
  J-Global ID：201402211635618704
• クラスタ主成分分析による符号付き球面距離関数の圧縮　　　　　　　　　　　　　　　
  川口貴大; 岩崎慶
  情報処理学会全国大会講演論文集, Volume：76th, Number：4, First page：4.305-4.306, 11 Mar. 2014
  Japanese
  J-Global ID：201402263990959385
• 非等方性球面ガウス関数を用いた環境マップの近似手法　　　　　　　　　　　　　　　
  仲北和弘; 岩崎慶
  情報処理学会全国大会講演論文集, Volume：76th, Number：4, First page：4.307-4.308, 11 Mar. 2014
  Japanese
  J-Global ID：201402298957111689
• 氷結による亀裂のビジュアルシミュレーション　　　　　　　　　　　　　　　
  八木貴志; 岩崎慶
  情報処理学会全国大会講演論文集, Volume：76th, Number：4, First page：4.349-4.350, 11 Mar. 2014
  Japanese
  J-Global ID：201402268530323638
• 携帯端末でも動作する高精細画像生成アルゴリズムの開発と実装　　　　　　　　　　　　　　　
  岩崎慶
  電気通信普及財団研究調査報告書(CD-ROM), Number：28, First page：536, Last page：546, Dec. 2013
  Japanese
  ISSN：1346-0404, J-Global ID：201402261160221046
• 環境照明下の布の高速レンダリングと外観編集　　　　　　　　　　　　　　　
  水谷一貴; 岩崎慶; 土橋宜典; 西田友是
  Visual Computing/グラフィクスとCAD合同シンポジウム予稿集(CD-ROM), Volume：2013, First page：ROMBUNNO.9, 22 Jun. 2013
  Japanese
  J-Global ID：201302207789577496
• 雨氷のビジュアルシミュレーション　　　　　　　　　　　　　　　
  石川知一; YUE Yonghao; 渡辺大地; 岩崎慶; 土橋宜典; 柿本正憲; 近藤邦雄; 西田友是
  Visual Computing/グラフィクスとCAD合同シンポジウム予稿集(CD-ROM), Volume：2013, First page：ROMBUNNO.6, 22 Jun. 2013
  Japanese
  J-Global ID：201302247494720434
• 流体の流れ場のインタラクティブなデザイン　　　　　　　　　　　　　　　
  佐藤周平; 土橋宜典; 岩崎慶; 山本強; 落合啓之; 落合啓之
  Visual Computing/グラフィクスとCAD合同シンポジウム予稿集(CD-ROM), Volume：2013, First page：ROMBUNNO.5, 22 Jun. 2013
  Japanese
  J-Global ID：201302254915993660
• A Simplified Plane-parallel Scattering Model for Rendering Densely Distributed Objects such as Foliage　　　　　　　　　　　　　　　
  Mikio Shinya; Yoshinori Dobashi; Kei Iwasaki; Michio Shiraishi; Tomoyuki Nishita
  Volume：54, Number：4, 15 Apr. 2013
  Fast computation of multiple reflections and scattering among complex objects is very important in photorealistic rendering. This paper applies the plane-parallel scattering theory to the rendering of densely distributed objects such as trees. We propose a simplified plane-parallel scattering model that has very simple analytic solutions, allowing efficient evaluation of multiple scattering. A geometric compensation method is also introduced to cope with the infinite plane condition, required by the plane-parallel model. The scattering model was successfully applied to tree rendering. Comparison with a Monte Carlo method was made and reasonable agreement was confirmed. A rendering system based on the model was implemented and multiple inter-reflections were effectively obtained. The view-independent feature of the model allows fast display of scenes. The pre-computation is also modest, permitting interactive control of lighting conditions.------------------------------This is a preprint of an article intended for publication Journal ofInformation Processing(JIP). This preprint should not be cited. Thisarticle should be cited as: Journal of Information Processing Vol.21(2013) No.2 (online)DOI http://dx.doi.org/10.2197/ipsjjip.21.349------------------------------Fast computation of multiple reflections and scattering among complex objects is very important in photorealistic rendering. This paper applies the plane-parallel scattering theory to the rendering of densely distributed objects such as trees. We propose a simplified plane-parallel scattering model that has very simple analytic solutions, allowing efficient evaluation of multiple scattering. A geometric compensation method is also introduced to cope with the infinite plane condition, required by the plane-parallel model. The scattering model was successfully applied to tree rendering. Comparison with a Monte Carlo method was made and reasonable agreement was confirmed. A rendering system based on the model was implemented and multiple inter-reflections were effectively obtained. The view-independent feature of the model allows fast display of scenes. The pre-computation is also modest, permitting interactive control of lighting conditions.------------------------------This is a preprint of an article intended for publication Journal ofInformation Processing(JIP). This preprint should not be cited. Thisarticle should be cited as: Journal of Information Processing Vol.21(2013) No.2 (online)DOI http://dx.doi.org/10.2197/ipsjjip.21.349------------------------------
  English
  ISSN：1882-7764, CiNii Articles ID：110009579581, CiNii Books ID：AN00116647
• CG 写実的レンダリング　　　　　　　　　　　　　　　
  岩崎慶
  画像ラボ, Volume：24, Number：4, First page：41, Last page：48, 10 Apr. 2013
  Japanese
  ISSN：0915-6755, J-Global ID：201302260127294484, CiNii Articles ID：40019666974, CiNii Books ID：AN10164169
• Global Illumination Computation Using Replica Exchange Method Based on Locality Relaxation of Light Path Space　　　　　　　　　　　　　　　
  大津久平; YUE Yonghao; HOU Qiming; 岩崎慶; CHEN Bing‐Yu; 土橋宜典; 西田友是
  映像情報メディア学会技術報告, Volume：37, Number：17(AIT2013 33-119), First page：1, Last page：4, 08 Mar. 2013
  Methods for computing global illumination using Markov Chain Monte Carlo techniques generate a new light path by locally mutating an already generated light path. Such methods can generate light paths carrying large energies in high probabilities, aiming at higher computation efficiency. However, using the mutation strategies proposed in previous methods, when the energy distribution of the light paths is highly localized (i.e., there are spiky peaks), the generated light paths tend to get stuck in such localized regions, thus the computation could be non-robust. To resolve this problem, we propose a new framework for global illumination computation based on a replica exchange method. In our method, we introduce a set of auxiliary path spaces whose localities are gradually relaxed, and apply a replica exchange method to this set of spaces. Using our method, we can mutate light paths through the relaxed path spaces, even if the energy distribution in the original path space is highly localized. Hence, we can robustly generate light paths over the whole path space.
  The Institute of Image Information and Television Engineers, Japanese
  ISSN：1342-6893, J-Global ID：201302286269548539, CiNii Articles ID：110009597862, CiNii Books ID：AN1059086X
• 粒状物体と布の連成シミュレーション　　　　　　　　　　　　　　　
  平岡勇作; 岩崎慶
  電子情報通信学会大会講演論文集, Volume：2013, Number：2, First page：126, Last page：126, 05 Mar. 2013
  The Institute of Electronics, Information and Communication Engineers, Japanese
  ISSN：1349-1369, J-Global ID：201302264878094338, CiNii Articles ID：110009711875, CiNii Books ID：AN10471452
• 仮想照明を考慮したMRシーンのレンダリング　　　　　　　　　　　　　　　
  北出晋一; 岩崎慶
  電子情報通信学会大会講演論文集, Volume：2013, Number：2, First page：127, Last page：127, 05 Mar. 2013
  The Institute of Electronics, Information and Communication Engineers, Japanese
  ISSN：1349-1369, J-Global ID：201302296693576963, CiNii Articles ID：110009711876, CiNii Books ID：AN10471452
• レプリカ交換法を用いた新たな大域照明計算法の一検討　　　　　　　　　　　　　　　
  楽詠こう; 大津久平; 候啓明; 岩崎慶; 陳炳宇; 土橋宜典; 西田友是
  画像電子学会誌(CD-ROM), Volume：42, Number：1, First page：120, Last page：121, 30 Jan. 2013
  Japanese
  ISSN：2186-716X, J-Global ID：201302202758790645
• 水中での髪の毛のシミュレーション　　　　　　　　　　　　　　　
  雪本英輝; 岩崎慶
  情報処理学会関西支部支部大会講演論文集(CD-ROM), Volume：2013, First page：ROMBUNNO.G-13, 2013
  Japanese
  ISSN：1884-197X, J-Global ID：201302230699054151, CiNii Articles ID：170000079669
• 所望の集光模様を生成するための連続面からなる透明物体の形状設計法　　　　　　　　　　　　　　　
  YUE Yonghao; 岩崎慶; CHEN Bing‐Yu; 土橋宜典; 西田友是
  Visual Computing/グラフィクスとCAD合同シンポジウム予稿集(CD-ROM), Volume：2012, First page：ROMBUNNO.33, 23 Jun. 2012
  Japanese
  J-Global ID：201202253580558677
• スパイクの動的変形を考慮した磁性流体のビジュアルシミュレーション　　　　　　　　　　　　　　　
  石川知一; YUE Yonghao; 岩崎慶; 土橋宜典; 西田友是
  Visual Computing/グラフィクスとCAD合同シンポジウム予稿集(CD-ROM), Volume：2012, First page：ROMBUNNO.23, 23 Jun. 2012
  Japanese
  J-Global ID：201202254391567505
• 球面ガウス関数を用いた微細なスケールのBRDF編集　　　　　　　　　　　　　　　
  岩崎慶; 土橋宜典; 西田友是
  Visual Computing/グラフィクスとCAD合同シンポジウム予稿集(CD-ROM), Volume：2012, First page：ROMBUNNO.13, 23 Jun. 2012
  Japanese
  J-Global ID：201202278094224867
• 気泡を考慮した氷結シミュレーション　　　　　　　　　　　　　　　
  西野孝則; 岩崎慶; 土橋宜典; 西田友是
  Visual Computing/グラフィクスとCAD合同シンポジウム予稿集(CD-ROM), Volume：2012, First page：ROMBUNNO.7, 23 Jun. 2012
  Japanese
  J-Global ID：201202279810896983
• Fast Visualization of Fluid Simulation using Multi‐GPU　　　　　　　　　　　　　　　
  豊田将千; 岩崎慶
  映像情報メディア学会技術報告, Volume：36, Number：19(ME2012 70-79/AIT2012 91-100), First page：13, Last page：14, 16 May 2012
  Visual simulation of natural phenomena is one of the most important research topics in the field of computer graphics, and has been widely studied such as fire, smoke, ice, and water. Realistic images of natural phenomena obtained by using visual simulations are widely used in various applications such as movies, commercial films, and games, Among these natural phenomena, simulations of fluids are used in many movies and commercial films, Although many methods have been proposed to visualize the results of fluid simulations, previous methods are computationally expensive and the extracted surfaces are bumpy. We address these problems and accelerate the visualization of particle-based simulations using multi-GPU. Our method can extract surfaces from particle-based simulations and render surfaces within a second while previous methods took 23 min.
  The Institute of Image Information and Television Engineers, Japanese
  ISSN：1342-6893, J-Global ID：201202250863916287, CiNii Articles ID：110009480472, CiNii Books ID：AN1059086X
• コンピュータグラフィクスの新展開 1 写実的レンダリング　　　　　　　　　　　　　　　
  岩崎慶
  情報処理, Volume：53, Number：6, First page：556, Last page：561, 15 May 2012
  Japanese
  ISSN：0447-8053, J-Global ID：201202236651299382, CiNii Articles ID：40019322065, CiNii Books ID：AN00116625
• ベクタ画像化におけるカラーフィッティングの高速化　　　　　　　　　　　　　　　
  谷垣祐司; 岩崎慶
  電子情報通信学会大会講演論文集, Volume：2012, Number：2, First page：4, Last page：4, 06 Mar. 2012
  The Institute of Electronics, Information and Communication Engineers, Japanese
  ISSN：1349-1369, J-Global ID：201202248014245137, CiNii Articles ID：110009462050, CiNii Books ID：AN10471452
• BTFのベクタ画像化　　　　　　　　　　　　　　　
  重松真太朗; 岩崎慶
  電子情報通信学会大会講演論文集, Volume：2012, Number：2, First page：5, Last page：5, 06 Mar. 2012
  The Institute of Electronics, Information and Communication Engineers, Japanese
  ISSN：1349-1369, J-Global ID：201202250692718562, CiNii Articles ID：110009462051, CiNii Books ID：AN10471452
• 環境照明下における布のレンダリング　　　　　　　　　　　　　　　
  水谷一貴; 岩崎慶
  情報処理学会関西支部支部大会講演論文集(CD-ROM), Volume：2012, First page：ROMBUNNO.G-18, 2012
  Japanese
  ISSN：1884-197X, J-Global ID：201302245123094872
• Report of Visual Computing Workshop 2011 (VCWS2011)　　　　　　　　　　　　　　　
  岩崎 慶
  画像電子学会誌 The journal of the Institute of Image Electronics Engineers of Japan : visual computing, devices & communications, Volume：41, Number：1, First page：88, Last page：93, Jan. 2012
  画像電子学会, Japanese
  ISSN：2186-716X, CiNii Articles ID：40019193831, CiNii Books ID：AA12563298
• Visual Simulation of the Magnetic Fluid to Represent the Spike Phenomenon　　　　　　　　　　　　　　　
  石川 知一; Yonghao Yue; 岩崎 慶; 土橋 宜典; 西田 友是
  研究報告グラフィクスとCAD（CG）, Volume：2011, Number：7, First page：1, Last page：8, 28 Aug. 2011
  本稿では，磁性流体に注目する．磁性流体は，流体と磁性体の両方の振る舞いをし，この特性により，磁場に沿った 「スパイク状」 の形を生成する．磁性流体は，芸術作品として多用される．我々の目標は，磁性流体の芸術作品をシミュレーションすることです．しかしながら，磁性流体のスパイク形状は，完全に物理ベースの方法ではシミュレーションすることが困難であることが知られている．そこで，我々は SPH（smoothed particle hydrodynamics） 法と手続き型のアプローチを組み合わせた，視覚的にもっともらしい手法を提案する．結果として，磁力が印加されるときに磁性流体にスパイク形状が生成される様子をシミュレーションできることを示す．In this paper, we focus on magnetic fluids. Magnetic fluids behave as both fluids and as magnetic bodies, and these characteristics allow them to generate 'spike-like' shapes along a magnetic field. Magnetic fluids are popular materials for use in works of art. Our goal is to simulate such works of art. It is known, however, that the spikes are difficult to simulate using fully physical-based methods. Therefore, we propose a visually plausible method that combines a procedural approach together with the SPH (smoothed particle hydrodynamics) method. We demonstrate that the spike shapes can be simulated when a magnetic force is applied.
  Japanese
  CiNii Articles ID：110008601850, CiNii Books ID：AN10100541
• 所望の集光模様を生成する透明物体の一設計法　　　　　　　　　　　　　　　
  YUE Yonghao; 岩崎慶; CHEN Bing‐Yu; 土橋宜典; 西田友是
  Visual Computing/グラフィクスとCAD合同シンポジウム予稿集(CD-ROM), Volume：2011, First page：RENDARINGU,YONGHAO YUE, 24 Jun. 2011
  Japanese
  J-Global ID：201102202979972212
• 雲のエンドレスアニメーションのリアルタイムレンダリング　　　　　　　　　　　　　　　
  西野孝則; 岩崎慶; 土橋宜典
  Visual Computing/グラフィクスとCAD合同シンポジウム予稿集(CD-ROM), Volume：2011, First page：ANIMESHON,NISHINOTAKANORI, 24 Jun. 2011
  Japanese
  J-Global ID：201102209198339608, CiNii Articles ID：10030682575
• 球近似と符号付き球面距離関数による動的シーンのリアルタイムレンダリング　　　　　　　　　　　　　　　
  古家亙; 岩崎慶; 土橋宜典; 西田友是
  Visual Computing/グラフィクスとCAD合同シンポジウム予稿集(CD-ROM), Volume：2011, First page：RENDARINGU,FURUYAWATARU, 24 Jun. 2011
  Japanese
  J-Global ID：201102226586915310
• 球面ガウス関数を用いた全周波環境照明下の動的シーンの高速レンダリング　　　　　　　　　　　　　　　
  古家亙; 岩崎慶
  Volume：2011, Number：1, First page：81, Last page：82, 02 Mar. 2011
  全周波照明環境下でのリアルタイムな照明計算手法として、照明を近似する基底関数に球面ガウス関数を用いた照明計算手法が提案されている。しかし、この手法は静的なシーンの描画を前提としている。本研究は、この手法を動的なシーンに対しても適用できるように拡張する。描画対象のオブジェクトの表面上の点におけるガウス関数の中心ベクトルと、最も近くにある可視境界へ向かうベクトルとの角距離を、デプスマップを用いて判定する。これにより、可視判定関数を評価し、シーン内の物体の陰影付け、および、影を描画する。このように、従来手法が事前計算により実現していた可視判定関数を動的に求めることにより、動的なシーンに対応する。
  Japanese
  CiNii Articles ID：170000089143, CiNii Books ID：AN00349328
• 光経路の前計算によるrandom discrete mediaの高速レンダリング　　　　　　　　　　　　　　　
  豊田将千; 岩崎慶
  Volume：2011, Number：1, First page：83, Last page：85, 02 Mar. 2011
  雪や砂糖といった多くの細かい粒子からなるrandom discrete mediaの環境照明下の高速レンダリング法を提案する.
  random discrete media内部での光の反射・屈折・吸収といった振る舞いをGPU上で近似計算を用いることにより高速に前計算する.
  光が進む経路あらかじめを求めることにより高速なレンダリングを実現する.
  また,これらの経路情報を 用いることにより環境マップの変更や回転といったリライティングを実現する.
  Japanese
  CiNii Articles ID：110008601356, CiNii Books ID：AN00349328
• 多重散乱光を考慮した動的な雲のリアルタイムレンダリング　　　　　　　　　　　　　　　
  西野孝則; 岩崎慶; 土橋宜典
  Volume：2011, Number：1, First page：87, Last page：89, 02 Mar. 2011
  屋外景観映像の作成において,写実的かつ動的な雲の表示は重要である.
  しかし,写実的な雲を表示するには多重散乱光を考慮する必要があり,
  毎フレームにおいて多重散乱光の輝度計算を行うのは非常に計算コストが
  高い.そこで,任意の雲の密度分布をウェーブレット関数で表し,
  ボクセル間の密度の積分値を前計算しておく.そして,前計算した
  積分値と各ウェーブレット関数の重みとの累積をとることにより,
  任意の雲のボクセル間の減衰率を非線形近似で表し,輝度計算を
  高速化する手法を提案する.また,膨大な量の前計算データを圧縮し,
  GPU上に格納することによりCUDAを用いたリアルタイムレンダリングを
  実現した.
  Japanese
  CiNii Articles ID：110008601358, CiNii Books ID：AN00349328
• 光経路情報の前計算によるrandom discrete mediaの高速レンダリング　　　　　　　　　　　　　　　
  豊田将千; 岩崎慶
  情報処理学会全国大会講演論文集, Volume：73rd, Number：4, First page：4.83-4.84, 02 Mar. 2011
  Japanese
  J-Global ID：201102235754525000
• 多重散乱を考慮した動的な雲のリアルタイムレンダリング　　　　　　　　　　　　　　　
  西野孝則; 岩崎慶; 土橋宜典
  情報処理学会全国大会講演論文集, Volume：73rd, Number：4, First page：4.87-4.88, 02 Mar. 2011
  Japanese
  J-Global ID：201102241002133340
• 球面ガウス関数を用いた全周波環境照明下の動的シーンの高速レンダリング　　　　　　　　　　　　　　　
  古家亙; 岩崎慶
  情報処理学会全国大会講演論文集, Volume：73rd, Number：4, First page：4.81-4.82, 02 Mar. 2011
  Japanese
  J-Global ID：201102273414545501
• 電離圏モデルを利用したオーロラのシミュレーション　　　　　　　　　　　　　　　
  石川知一; YUE Yonghao; 岩崎慶; 土橋宜典; 西田友是
  Volume：2011, 2011
  J-Global ID：201102219780374081
• Spherical Harmonic Exponentiationを用いた動的な雲の高速レンダリング　　　　　　　　　　　　　　　
  江口千央; 土橋宜典; 山本強; 岩崎慶
  電子情報通信学会論文誌 A, Volume：J94-A, Number：1, First page：30, Last page：36, 01 Jan. 2011
  本論文では,動的な雲を効率的にレンダリングする手法を提案する.屋外景観のアニメーション映像を作成する場合,時々刻々と変化する雲の映像を作成する必要がある.このとき,リアルな映像作成のためには,雲の三次元密度分布を考慮した表示が求められる.しかし,動的な雲に対して毎フレーム輝度計算を行って画像生成を行うことは計算コストが高い点が問題となる.そこで,本研究では,この問題を解決するため,前もって有限時間の長さの動的な雲のデータベースを用意しておく手法を提案する.このデータベースを利用して,太陽位置や視点位置にかかわらず,任意の長さの動的な雲の映像を高速に生成する.動的な雲のボリュームデータは,Video Textureと呼ばれる動的なテクスチャを合成する手法を利用して生成する.また,Spherical Harmonic Exponentiationを応用することで高速レンダリングを実現する.提案法により,太陽直接光及び天空光に照射された動的な雲の効率的な表示が可能である.
  The Institute of Electronics, Information and Communication Engineers, Japanese
  ISSN：0913-5707, J-Global ID：201102248224501597, CiNii Articles ID：110008007080, CiNii Books ID：AN10013345
• 粒子ベース流体シミュレーションデータの圧縮　　　　　　　　　　　　　　　
  和田耕太; 岩崎慶
  情報処理学会関西支部支部大会講演論文集(CD-ROM), Volume：2011, First page：ROMBUNNO.C-23, 2011
  Japanese
  ISSN：1884-197X, J-Global ID：201102299435233410, CiNii Articles ID：170000069382
• Diffusion Curve Imageを用いた屈折マッピング　　　　　　　　　　　　　　　
  菅田佳博; 岩崎慶
  情報処理学会関西支部支部大会講演論文集(CD-ROM), Volume：2011, First page：ROMBUNNO.C-22, 2011
  Japanese
  ISSN：1884-197X, J-Global ID：201102214727691006
• On Optimal Space Partitioning for Unbiased, Adaptive Free Path Sampling　　　　　　　　　　　　　　　
  YUE Yonghao; 岩崎慶; CHEN Bing‐Yu; 土橋宜典; 西田友是
  情報処理学会研究報告(CD-ROM), Volume：2010, Number：4, First page：ROMBUNNO.CG-141,3, 15 Dec. 2010
  Japanese
  ISSN：2186-2583, J-Global ID：201102209489614746
• On Optimal Space Partitioning for Unbiased, Adaptive Free Path Sampling　　　　　　　　　　　　　　　
  楽 詠灝; 岩崎 慶; 陳 炳宇; 土橋 宜典; 西田 友是
  Volume：2010, Number：3, First page：1, Last page：6, 01 Nov. 2010
  光の散乱効果を考慮した関与媒質の写実的レンダリングは，CG 分野において重要であり，しばしばモンテカルロ法によって計算される．モンテカルロ法による散乱計算では，自由行程サンプリング (連続する散乱イベント間の距離 (自由行程) をサンプリングする方法) が重要な技術である．我々は先行研究において，統計的に不偏でかつ適合的な自由行程サンプリング法 14)，15) を提案し，従来法に比べてサンプリング効率を大きく改善した．その方法の鍵となる概念は，媒質の存在する空間領域を，媒質の平均自由行程の空間分布に基づいて分割し，自由行程を適合的にサンプリングすることである．このため，空間分割のスキームがサンプリングの効率性において重要である．本稿では，我々は理論的にサンプリング効率が最適となる空間分割法を示す．Photo-realistic rendering of participating media with light scattering in consideration is important in computer graphics, and is typically computed using Monte Carlo based methods. The key technique in such methods is the free path sampling, which is used for determining the distance (free path) between successive scattering events. In our previous work, we proposed an unbiased and adaptive free path sampling method14),15) and the sampling efficiency was significantly improved over existing methods. The key concept of that method is to partition the spatial domain according to the spatial variation of the mean free path of the medium and to sample the free path in an adaptive manner. Thus, the space partitioning scheme is important for the sampling efficiency. In this paper, we show a space partitioning scheme that is theoretically proven to make the sampling efficiency optimal.
  Japanese
  ISSN：1884-0930, CiNii Articles ID：110007997502, CiNii Books ID：AN10100541
• 動的な雲のための多重散乱光の高速計算法　　　　　　　　　　　　　　　
  西野孝則; 岩崎慶; 土橋宜典
  Volume：2010, Number：2010, 22 Sep. 2010
  Japanese
  CiNii Articles ID：170000063300
• 融解後の水を考慮した粒子ベース氷塊融解シミュレーション　　　　　　　　　　　　　　　
  内田英行; 岩崎慶; 土橋宜典; 西田友是
  Visual Computing/グラフィクスとCAD合同シンポジウム予稿集(CD-ROM), Volume：2010, First page：RYUTAISHIMYURESHON,UCHIDAHIDEYUKI, 26 Jun. 2010
  Japanese
  J-Global ID：201002231480768927
• 非均質関与媒質のレンダリングのための不偏で効率的な重点的サンプリング手法　　　　　　　　　　　　　　　
  YUE Yonghao; 岩崎慶; CHEN Bing‐Yu; 土橋宜典; 西田友是
  Visual Computing/グラフィクスとCAD合同シンポジウム予稿集(CD-ROM), Volume：2010, First page：RENDARINGU,YONGHAO YUE, 26 Jun. 2010
  Japanese
  J-Global ID：201002244374072977
• 前計算減衰率カットによる多重散乱を考慮した動的な雲の高速レンダリング　　　　　　　　　　　　　　　
  西尾竜平; 岩崎慶; 土橋宜典
  Visual Computing/グラフィクスとCAD合同シンポジウム予稿集(CD-ROM), Volume：2010, First page：RENDARINGU,NISHIORYUHEI, 26 Jun. 2010
  Japanese
  J-Global ID：201002248387876523
• 異方性Plane‐Parallel散乱モデルによる毛髪状物体の高速レンダリング　　　　　　　　　　　　　　　
  新谷幹夫; 白石路雄; 土橋宜典; 岩崎慶; 西田友是
  Visual Computing/グラフィクスとCAD合同シンポジウム予稿集(CD-ROM), Volume：2010, First page：RENDARINGU,SHIN'YAMIKIO, 26 Jun. 2010
  Japanese
  J-Global ID：201002288266025153
• 対流計算を高速化した氷塊融解ビジュアルシミュレーション　　　　　　　　　　　　　　　
  上田悟史; 内田英行; 岩崎慶
  情報処理学会全国大会講演論文集, Volume：72nd, Number：4, First page：4.311-4.312, Last page：312, 08 Mar. 2010
  Japanese
  J-Global ID：201002265094701208, CiNii Articles ID：110008137352, CiNii Books ID：AN00349328
• 携帯カメラを用いたPRTのための環境マップ生成法　　　　　　　　　　　　　　　
  中西良太; 岩崎慶
  情報処理学会全国大会講演論文集, Volume：72nd, Number：4, First page：4.329-4.330, Last page：330, 08 Mar. 2010
  Japanese
  J-Global ID：201002297393163203, CiNii Articles ID：110008137361, CiNii Books ID：AN00349328
• 球面ガウス関数を用いた全周波照明環境下における間接照明計算　　　　　　　　　　　　　　　
  古家亙; 岩崎慶
  情報処理学会関西支部支部大会講演論文集(CD-ROM), Volume：2010, First page：ROMBUNNO.G-03, 2010
  Japanese
  ISSN：1884-197X, J-Global ID：201002279394829789, CiNii Articles ID：170000063299
• 動的な雲のための多重散乱光の高速計算法　　　　　　　　　　　　　　　
  西野孝則; 岩崎慶; 土橋宜典
  情報処理学会関西支部支部大会講演論文集(CD-ROM), Volume：2010, First page：ROMBUNNO.G-04, 2010
  Japanese
  ISSN：1884-197X, J-Global ID：201002248353295440
• cutを用いた雲の多重散乱の高速計算法　　　　　　　　　　　　　　　
  西尾竜平; 岩崎慶; 土橋宜典
  Volume：2009, Number：2009, 29 Sep. 2009
  Japanese
  CiNii Articles ID：170000063879
• Inverse Problem Approach for BRDF Modeling　　　　　　　　　　　　　　　
  岩崎 慶; 土橋 宜典; 西田友是
  Volume：50, Number：8, First page：1917, Last page：1925, 15 Aug. 2009
  本稿は逆問題アプローチに基づいたBRDFモデリング手法を提案する．提案法は，ユーザが指定した物体の外観に合うようなBRDFを計算する．BRDFを基底関数の線形和で表現することにより，物体表面の放射輝度は基底関数を用いて表現される．これにより，求めたいBRDFの計算は，ユーザが指定した輝度と基底関数で表現された放射輝度の差の二乗和を最小にする係数を求める問題に帰着される．BRDFが満たすべき特徴は線形制約条件として表現される．この最小化問題は，線形制約付き最小二乗法を用いることによりインタラクティブに解くことができる．提案法により，固定された複雑な照明下において直接BRDFをデザインすることができる．また，得られたBRDFを用いて動的な照明下で視点を移動させた結果をインタラクティブにレンダリングすることができる．This paper presents a BRDF modeling method, based on an inverse problem approach. Our method calculates BRDFs to match the appearance of the object specified by the user. By representing BRDFs by a linear combination of basis functions, outgoing radiances of the object surface can be represented using basis functions. The calculation of the desired BRDF results from calculating the corresponding coefficients of basis functions that minimize the sum of differences between the outgoing radiances, represented using basis functions and user specified radiances. The properties that BRDFs must satisfy are described by linear constraint conditions. This minimization problem can be solved, interactively, using a linearly constrained least squares approach. Thus, our method allows the user to design BRDFs directly, under fixed complex lighting and viewpoint, and to view the rendering results interactively, under dynamic lighting and viewpoint.
  Japanese
  ISSN：1882-7764, CiNii Articles ID：110007970480, CiNii Books ID：AN00116647
• Inverse Problem Approach for BRDF Modeling　　　　　　　　　　　　　　　
  岩崎慶; 土橋宜典; 西田友是
  情報処理学会論文誌ジャーナル(CD-ROM), Volume：50, Number：8, First page：1917, Last page：1925, 15 Aug. 2009
  Japanese
  ISSN：1882-7837, J-Global ID：200902272015333920
• 多重散乱モデルの効率化と樹木レンダリングへの応用　　　　　　　　　　　　　　　
  新谷幹夫; 土橋宜典; 白石路雄; 岩崎慶; 西田友是
  Visual Computing/グラフィクスとCAD合同シンポジウム予稿集(CD-ROM), Volume：2009, First page：ROMBUNNO.18, 25 Jun. 2009
  Japanese
  J-Global ID：200902261002341794, CiNii Articles ID：10030143009
• 動的BRDFを考慮した動的シーンのインタラクティブレンダリング　　　　　　　　　　　　　　　
  岩崎慶; 宮前雄生; 土橋宜典; 西田友是
  Visual Computing/グラフィクスとCAD合同シンポジウム予稿集(CD-ROM), Volume：2009, First page：ROMBUNNO.48, 25 Jun. 2009
  Japanese
  J-Global ID：200902231316772475
• 雲微物理を考慮した雨雲形成のビジュアルシミュレーション　　　　　　　　　　　　　　　
  YUE Yonghao; 岩崎慶; CHEN Bing‐Yu; 土橋宜典; 西田友是
  Visual Computing/グラフィクスとCAD合同シンポジウム予稿集(CD-ROM), Volume：2009, First page：ROMBUNNO.01, 25 Jun. 2009
  Japanese
  J-Global ID：200902218460271271
• GPUを用いた粒子ベース氷塊融解シミュレーションの高速化　　　　　　　　　　　　　　　
  内田英行; 上田悟史; 岩崎慶; 吉本富士市
  情報処理学会全国大会講演論文集, Volume：71st, Number：4, First page：4.269-4.270, Last page：270, 10 Mar. 2009
  Japanese
  J-Global ID：200902226357338484, CiNii Articles ID：110007505651, CiNii Books ID：AN00349328
• Interactive Rendering Method for Sea Surfaces Taking into Account Multiple Scattering　　　　　　　　　　　　　　　
  KAKUTA Kensuke; IWASAKI Kei; YOSHIMOTO Fujiichi
  全国大会講演論文集, Volume：71, Number：0, First page：267, Last page：268, 10 Mar. 2009
  Japanese
  CiNii Articles ID：110007505650, CiNii Books ID：AN00349328
• Fast Rendering of Dynamic Scenes using Visibility Cuts　　　　　　　　　　　　　　　
  宮前雄生; 岩崎慶; 吉本富士市
  情報処理学会研究報告, Volume：2009, Number：12(CG-134), First page：101, Last page：106, 09 Feb. 2009
  To render photo-realistic images efficiently, many rendering methods using environment map lighting have been proposed. We propose a fast rendering method of dynamic scenes under all-frequency environment lighting with dynamic BRDFs. Our method precomputes the self-occlusion and occlusions due to other objects. By integrating these occlusions in the rendering process, our method can render dynamic scenes efficiently. The occlusion information is represented by using visibility cuts. This makes it possible to change BRDFs in the rendering process. We develop an efficient representation of visibility cuts, and achieved to reduce the precomputed data and efficient rendering.
  Information Processing Society of Japan (IPSJ), Japanese
  ISSN：0919-6072, J-Global ID：200902217732171992, CiNii Articles ID：110007163760, CiNii Books ID：AN10100541
• Cutを用いた雲の多重散乱の高速計算法　　　　　　　　　　　　　　　
  西尾竜平; 岩崎慶; 土橋宜典
  情報処理学会関西支部支部大会講演論文集(CD-ROM), Volume：2009, First page：ROMBUNNO.E-06, 2009
  Japanese
  ISSN：1884-197X, J-Global ID：200902260467978989, CiNii Articles ID：170000063879
• 融解後の水を考慮した粒子ベース氷塊融解シミュレーション　　　　　　　　　　　　　　　
  内田英行; 岩崎慶
  情報処理学会関西支部支部大会講演論文集(CD-ROM), Volume：2009, First page：ROMBUNNO.E-05, 2009
  Japanese
  ISSN：1884-197X, J-Global ID：200902278582602557, CiNii Articles ID：170000063878
• Calculation and Interpolation of Reflectance and Transmittance Distribution of Scattering Materials　　　　　　　　　　　　　　　
  Mikio Shinyat; Michio Shiraish; Yoshinori Dobashi; Kei Iwasaki; Tomoyuki Nishita
  Journal of the Institute of Image Electronics Engineers of Japan, Volume：38, Number：4, First page：423, Last page：431, 2009
  Rendering scattering materials is an important issue in realistic rendering. This paper describes calculation and interpolation methods of BRDFs/BTDFs (Bidirectional Reflectance/Transmittance Distribution Functions) of scattering materials. We introduced the plane-parallel scattering theory, which enables us analytic calculation of BRDFs/BTDFs of uniform scattering materials. We analysed calculated BRDFs/BTDFs and proposed their interpolation methods against scattering parameters and width of scattering materials. © 2009, The Institute of Image Electronics Engineers of Japan. All rights reserved.
  English
  DOI：https://doi.org/10.11371/iieej.38.423
  DOI ID：10.11371/iieej.38.423, ISSN：1348-0316, J-Global ID：200902286157952903, SCOPUS ID：85024714321
• 固有解を用いた表面下散乱の高速表示　　　　　　　　　　　　　　　
  新谷幹夫; 白石路雄; 土橋宜典; 岩崎慶; 西田友是
  Visual Computing/グラフィクスとCAD合同シンポジウム予稿集(CD-ROM), Volume：2008, First page：ROMBUNNO.1, 21 Jun. 2008
  Japanese
  J-Global ID：200902216140730305
• Portal‐to‐Vertex Light Transferによる高周波環境光と局所光源を含む屋内照明設計　　　　　　　　　　　　　　　
  YUE Yonghao; 岩崎慶; 土橋宜典; 西田友是
  Visual Computing/グラフィクスとCAD合同シンポジウム予稿集(CD-ROM), Volume：2008, First page：ROMBUNNO.4, 21 Jun. 2008
  Japanese
  J-Global ID：200902274062892883
• 自己反射を考慮した鏡面反射物体のGPUレイトレーシング法　　　　　　　　　　　　　　　
  中谷聡志; 岩崎慶; 高木佐恵子; 吉本富士市
  情報処理学会全国大会講演論文集, Volume：70th, Number：4, First page：4.363-4.364, Last page：364, 13 Mar. 2008
  Japanese
  J-Global ID：200902221389116112, CiNii Articles ID：110006867719, CiNii Books ID：AN00349328
• 前計算放射輝度伝達法のための適応的メッシュ分割法　　　　　　　　　　　　　　　
  西本陽太; 岩崎慶; 高木佐恵子; 吉本富士市
  情報処理学会全国大会講演論文集, Volume：70th, Number：4, First page：4.407-4.408, Last page：408, 13 Mar. 2008
  Japanese
  J-Global ID：200902219856821181, CiNii Articles ID：110006867741, CiNii Books ID：AN00349328
• GPUを用いた水中の光跡の高速レンダリング　　　　　　　　　　　　　　　
  一木誠史; 岩崎慶; 高木佐恵子; 吉本富士市
  情報処理学会全国大会講演論文集, Volume：70th, Number：4, First page：4.361-4.362, Last page：362, 13 Mar. 2008
  Japanese
  J-Global ID：200902203780489782, CiNii Articles ID：110006867718, CiNii Books ID：AN00349328
• 任意形状の光源による大気散乱光の高速レンダリング　　　　　　　　　　　　　　　
  福井洋平; 岩崎慶; 高木佐恵子; 吉本富士市
  情報処理学会全国大会講演論文集, Volume：70th, Number：4, First page：4.365-4.366, Last page：366, 13 Mar. 2008
  Japanese
  J-Global ID：200902296325364333, CiNii Articles ID：110006867720, CiNii Books ID：AN00349328
• Visibility Cutsを用いた動的シーンの高速レンダリング　　　　　　　　　　　　　　　
  宮前雄生; 岩崎慶; 吉本富士市
  情報処理学会関西支部支部大会講演論文集, Volume：2008, First page：299, Last page：300, 2008
  Japanese
  J-Global ID：200902281032462139
• GPUを用いた粒子ベース氷塊融解シミュレーションの高速化　　　　　　　　　　　　　　　
  内田英行; 岩崎慶; 吉本富士市
  情報処理学会関西支部支部大会講演論文集, Volume：2008, First page：273, Last page：274, 2008
  Japanese
  J-Global ID：200902214541748956
• “Real-time Rendering of Specular Surfaces Considering Self-Reflection”　　　　　　　　　　　　　　　
  Kei Iwasaki; Fuji-Ichi Yoshimoto; Satoshi Nakatani
  Journal of the Institute of Image Electronics Engineers of Japan, Volume：37, Number：4, First page：405, Last page：411, 2008
  To render specular surfaces, reflections play an important role to enhance the realism. For concave surfaces, the effects of self-reflections that the surface reflects a part of the surface itself are necessary to create realistic images. This paper presents a real-time rendering of rigid specular surfaces taking into account self-reflections. In the preprocess, sample rays incident onto each vertex of the specular surface are traced taking into account the reflection, until they do not intersect the surface. The outgoing reflected directions are stored in look-up tables. In the rendering process, reflections of the environment taking into account the self-reflection are rendered by using the precomputed look-up tables. Our method accelerates the rendering by using a GPU and achieves real-time rendering. © 2008, The Institute of Image Electronics Engineers of Japan. All rights reserved.
  English
  DOI：https://doi.org/10.11371/iieej.37.405
  DOI ID：10.11371/iieej.37.405, ISSN：1348-0316, J-Global ID：200902250663238394, SCOPUS ID：85024735540
• Generalization of the Kubelka‐Munk Theory by Eigen‐value Analysys　　　　　　　　　　　　　　　
  新谷幹夫; 白石路雄; 土橋宜典; 岩崎慶; 西田友是
  情報処理学会研究報告, Volume：2007, Number：111(CG-129), First page：31, Last page：36, 12 Nov. 2007
  Kubelka-Munk theory analatically calculates reflectance and transparensy of scattering materials and is widely used in non-photo-realistic rendering. However, it does not prvide BRDF (Bidirectional Reflectance Distribution Function) and has been hard to be applied to photo-realistic rendeiring. This paper generalizes the theory and derives a quasi-analytic fomulae providing BRDFs of scattering layered uniform materials. The volume rendering equation is applied to a layered surface and analytically solved by using the eigen-value analysis. It also presents theories to concatenating multiple layered-materials, as well as their polynimial approximation.
  Information Processing Society of Japan (IPSJ), Japanese
  ISSN：0919-6072, J-Global ID：200902262924545441, CiNii Articles ID：110006531717, CiNii Books ID：AN10100541
• A Rendering Method for Sea Surfaces Taking into Account Occlusion　　　　　　　　　　　　　　　
  KAKUTA Kensuke; IWASAKI Kei; TAKAGI Saeko; YOSHIMOTO Fujiichi
  IPSJ SIG Notes, Volume：129, Number：111, First page：1, Last page：6, 12 Nov. 2007
  In the field of Computer Graphics, rendering of the sea surfaces is one of the most important research topics, and many methods have been proposed to render the sea surfaces. Previous methods have been proposed to render sea surfaces without occlusions. There exists no method for rendering sea surfaces occluded by objects such as the sea in the cave. In this paper, we present an efficient rendering method of sea surfaces occluded by objects. Our method precomputes the occlusion information and represents the occlusion information with spherical harmonics. This makes it possible to calculate the outgoing radiance from the water surface efficiently. As a result, we got possible to render sea surfaces occluded by objects realistically.
  Information Processing Society of Japan (IPSJ), Japanese
  ISSN：0919-6072, CiNii Articles ID：110006531712, CiNii Books ID：AN10100541
• 動的照明環境下の効率的なファイナルギャザリングのための階層ヒストグラム推定と光路の再利用　　　　　　　　　　　　　　　
  YUE Yonghao; 岩崎慶; 土橋宜典; 西田友是
  Visual Computing グラフィクスとCAD合同シンポジウム予稿集, Volume：2007, First page：51, Last page：56, 23 Jun. 2007
  Japanese
  DOI：https://doi.org/10.11371/aiieej.35vc.0.51.0
  DOI ID：10.11371/aiieej.35vc.0.51.0, J-Global ID：200902211113604290
• 準解析解を用いた多重散乱物質のレンダリング　　　　　　　　　　　　　　　
  新谷幹夫; 白石路雄; 土橋宜典; 岩崎慶; 西田友是
  Visual Computing グラフィクスとCAD合同シンポジウム予稿集, Volume：2007, First page：119, Last page：124, 23 Jun. 2007
  This paper presents a new method for visual simulation of multiple scattering phenomena. Quasi-analytic solutions are derived for layered uniform materials, and efficient rendering methods are developed by coupling these solutions with the ray-marching method.
  The Institute of Image Electronics Engineers of Japan, Japanese
  DOI：https://doi.org/10.11371/aiieej.35vc.0.119.0
  DOI ID：10.11371/aiieej.35vc.0.119.0, ISSN：2436-4371, eISSN：2436-4398, J-Global ID：200902281702666725, CiNii Articles ID：130006966782
• 多重薄膜で覆われた物体のリアルタイムレンダリング　　　　　　　　　　　　　　　
  上田克幸; 面家康孝; 岩崎慶; 高木佐恵子; 吉本富士市
  Visual Computing グラフィクスとCAD合同シンポジウム予稿集, Volume：2007, First page：185, Last page：190, 23 Jun. 2007
  Japanese
  DOI：https://doi.org/10.11371/aiieej.35vc.0.185.0
  DOI ID：10.11371/aiieej.35vc.0.185.0, J-Global ID：200902288042215355
• Image Retrieval System of Flowers―Improvement of Flower Region Extraction and User Interface―　　　　　　　　　　　　　　　
  植田裕司; 岩崎慶; 高木佐恵子; 吉本富士市
  画像電子学会研究会講演予稿, Volume：231st, First page：65, Last page：70, 08 Mar. 2007
  Japanese
  ISSN：0285-3957, J-Global ID：200902242466981473
• 曲面上におけるパーティクルベース高速流体シミュレーション　　　　　　　　　　　　　　　
  師 芳卓; 金森 由博; 岩崎 慶; 西田 友是
  Volume：2007, Number：1, First page：275, Last page：276, 06 Mar. 2007
  Japanese
  CiNii Articles ID：170000173128
• 自己反射を考慮した鏡面反射物体の高速レンダリング　　　　　　　　　　　　　　　
  中谷 聡志; 岩崎 慶; 高木 佐恵子; 吉本 富士市
  Volume：2007, Number：1, First page：269, Last page：270, 06 Mar. 2007
  Japanese
  CiNii Articles ID：170000173125
• 氷塊融解の粒子ベースビジュアルシミュレーション　　　　　　　　　　　　　　　
  森本 和範; 岩崎 慶; 高木 佐恵子; 吉本 富士市
  Volume：2007, Number：1, First page：273, Last page：274, 06 Mar. 2007
  Japanese
  CiNii Articles ID：170000173127
• Modification System for Improving 3D Facial Beauty　　　　　　　　　　　　　　　
  OKADA Yosuke; TAKAGI Saeko; IWASAKI Kei; YOSHIMOTO Fujiichi
  IPSJ SIG Notes, Volume：126, Number：13, First page：103, Last page：108, 19 Feb. 2007
  We introduce a new system that transforms 3D facial data into beautified ones which have the features as beautiful faces in general. The targets of beautification are eyebrows, eyes, nose, mouth, and face contour. The operations for beautification are modifications of shapes and arrangement of the targets. The levels of the beautification can be controlled according to the parameter values input by a user, and the system can make beautified facial models matched to the user's favor. The effectiveness of the proposed system was confirmed from the experimental result on the proposed system and beautified facial models.
  Information Processing Society of Japan (IPSJ), Japanese
  ISSN：0919-6072, CiNii Articles ID：110006224762, CiNii Books ID：AN10100541
• Real-time particle-based method for simulating fluid flows on surfaces　　　　　　　　　　　　　　　
  Yoshitaka Moro; Kei Iwasaki; Yoshinori Dobashi; Tomoyuki Nishita
  Kyokai Joho Imeji Zasshi/Journal of the Institute of Image Information and Television Engineers, Volume：61, Number：10, First page：1457, Last page：1462, 2007
  Physically based fluid simulation is one of the most important research topics in computer graphics. Although many methods have been developed that use 3D or 2D grids to simulate fluids, there are few methodd for simulating fluid flows on surfaces. We present a real-time particle-based simulation method for the flows on surfaces. The surfaces are parameterized in a 2D parameter domain and physical quantities of particles are calculated in the parameter domain. The flows are simulated by updating the physical quantities of the particles, and the simulation is accelerated with a GPU. Our method simulates the fluid flows of 30,000 particles in real-time.
  Inst. of Image Information and Television Engineers, Japanese
  DOI：https://doi.org/10.3169/itej.61.1457
  DOI ID：10.3169/itej.61.1457, ISSN：1342-6907, J-Global ID：200902292462872340, SCOPUS ID：36649028881
• Fast Calculation of Interreflection for Dynamic Scenes Taking into account Glossy Surfaces　　　　　　　　　　　　　　　
  岩崎慶; 土橋宜典; 吉本富士市; 西田友是
  情報処理学会研究報告, Volume：2006, Number：119(CG-125), First page：113, Last page：118, 16 Nov. 2006
  Japanese
  ISSN：0919-6072, J-Global ID：200902217383066795, CiNii Articles ID：10018470099, CiNii Books ID：AN10100541
• 素人のための手描きキャラクタ改良支援システム　　　　　　　　　　　　　　　
  森啓年; 岩崎慶; 高木佐恵子; 吉本富士市
  情報科学技術フォーラム, Volume：FIT 2006, First page：239, Last page：242, 21 Aug. 2006
  Forum on Information Technology, Japanese
  J-Global ID：200902201250346791, CiNii Articles ID：110007640949, CiNii Books ID：AA1197723X
• Radiance Grid Pyramid: A Fast Photon Mapping Suited for Final Gathering　　　　　　　　　　　　　　　
  YUE Yong‐Hao; 岩崎慶; 西田友是
  情報処理学会研究報告, Volume：2006, Number：91(CG-124), First page：7, Last page：12, 17 Aug. 2006
  In this paper, we present a fast photon mapping method well suited for final gathering in a global illumination algorithm. We generate a hierarchical grid (called a grid pyramid) to store photon energies. Using a grid pyramid, we can estimate radiance without the nearest neighbor search, whose computational cost is high. Our method can handle low-frequent glossy BRDFs by adding photon energy directly into the grid pyramid, according to the photon's outgoing direction. Using our method, the computational speed for indirect illumination is an order of magnitude faster than the traditional photon mapping method. Additionally, our method is efficient in memory since we do not store photon data for individual photons and grids are generated only where geometry primitives exist.
  Information Processing Society of Japan (IPSJ), Japanese
  ISSN：0919-6072, J-Global ID：200902257826858667, CiNii Articles ID：110004824163, CiNii Books ID：AN10100541
• 動的なシーンのための相互反射を考慮した前計算放射輝度伝達法　　　　　　　　　　　　　　　
  岩崎慶; 土橋宜典; 田村尚希; JOHAN Henry; 吉本富士市; 西田友是
  Visual Computing グラフィクスとCAD合同シンポジウム予稿集, Volume：2006, First page：23, Last page：28, 22 Jun. 2006
  Japanese
  DOI：https://doi.org/10.11371/aiieej.34vc.0.23.0
  DOI ID：10.11371/aiieej.34vc.0.23.0, J-Global ID：200902276512746320
• 大規模なデータで構成された半透明物体のリアルタイムレンダリング　　　　　　　　　　　　　　　
  小田正志; 岩崎慶; 高木佐恵子; 吉本富士市
  Visual Computing グラフィクスとCAD合同シンポジウム予稿集, Volume：2006, First page：1, Last page：4, 22 Jun. 2006
  Japanese
  DOI：https://doi.org/10.11371/aiieej.34vc.0.1.0
  DOI ID：10.11371/aiieej.34vc.0.1.0, J-Global ID：200902267121930372
• A Study Support System for Beginners’ Pencil Sketches of Fruit　　　　　　　　　　　　　　　
  辻達也; 北内隆寛; 高木佐恵子; 松田憲幸; 曽我真人; 瀧寛和; 岩崎慶; 吉本富士市
  画像電子学会研究会講演予稿, Volume：224th, First page：125, Last page：130, 17 Mar. 2006
  Japanese
  ISSN：0285-3957, J-Global ID：200902248584061816, CiNii Articles ID：40007235445, CiNii Books ID：AN00348041
• Image Retrieval System of Flowers Using Mobile Phone　　　　　　　　　　　　　　　
  田畑惣太郎; 岩崎慶; 高木佐恵子; 吉本富士市
  画像電子学会研究会講演予稿, Volume：224th, First page：1, Last page：6, 17 Mar. 2006
  Japanese
  ISSN：0285-3957, J-Global ID：200902226297812815, CiNii Articles ID：40007235426, CiNii Books ID：AN00348041
• Information Retrieval System of Fishes Using a Cellular Phone　　　　　　　　　　　　　　　
  DONG Qiang; 岩崎慶; 高木佐恵子; 吉本富士市
  画像電子学会研究会講演予稿, Volume：224th, First page：7, Last page：12, 17 Mar. 2006
  Japanese
  ISSN：0285-3957, J-Global ID：200902205412877678, CiNii Articles ID：40007235427, CiNii Books ID：AN00348041
• Real‐time Rendering of Subsurface Scattering for Point‐sampled Geometry　　　　　　　　　　　　　　　
  小田正志; 岩崎慶; 高木佐恵子; 吉本富士市
  情報処理学会研究報告, Volume：2006, Number：18(CG-122), First page：57, Last page：62, 20 Feb. 2006
  We present a real-time rendering method of translucent object such as marble and milk for the point-sampled geometry. To render translucent objects, it is necessary to take into account the subsurface scattering of light. However, rendering translucent objects with the subsurface scattering takes long time. In our method, virtual points are set around the object uniformly. The intensities of the subsurface scattering of light are calculated at each virtual point. The intensities of points that represent the translucent object are interpolated by the intensities of the virtual points. Our method can render about 500,000 points with the subsurface scattering in real-time.
  Information Processing Society of Japan (IPSJ), Japanese
  ISSN：0919-6072, J-Global ID：200902251651358323, CiNii Articles ID：110004710324, CiNii Books ID：AN10100541
• A METHOD FOR IMPROVING THE SILHOUETTE LINES OF UNSKILLFUL HAND-DRAWN CURVES　　　　　　　　　　　　　　　
  MORI Hirotoshi; IWASAKI Kei; TAKAGI Saeko; YOSHIMOTO Fujiichi
  IEICE technical report, Volume：105, Number：501, First page：61, Last page：66, 03 Jan. 2006
  It is not easy for beginners to draw high quality pictures. If computers modify beginner's unskillful pictures into high quality ones, we are happy in many cases. To this end, we consider to use the features of pictures drawn by experts in drawing. We proposed a support system that modifies an unskillful curve drawn by a beginner in drawing into a high quality one using the features of curves drawn by an expert in drawing [see, Morimoto et al., IWAIT2005]. The modified curve preserved impression of the beginner's curve while having features of the expert's curve. Although the system could treat one of the two edge curves of the silhouette line of a hand-drawn curve, it could not treat the strength (width) of the silhouette line. In this paper, we propose a method to treat not only the general form (skeleton line) but also the strength of the silhouette line. Using a prototype system of the method, we experimented whether high quality hand-drawn-like silhouette lines (with strengths) were made. As a result, we confirmed that our method was effective in making those silhouette lines.
  The Institute of Electronics, Information and Communication Engineers, English
  ISSN：0913-5685, CiNii Articles ID：110004082580, CiNii Books ID：AN10013006
• A HANDY SYSTEM TO SUPPORT NOVICES' ILLUSTRATIONS　　　　　　　　　　　　　　　
  OHARA Toshiki; TAKAGI Saeko; IWASAKI Kei; YOSHIMOTO Fujiichi
  IEICE technical report, Volume：105, Number：500, First page：103, Last page：108, 02 Jan. 2006
  When novices at drawing are going to draw an illustration in mobile environments, there is a problem that they cannot handily get beautiful curves which they want to draw. This paper proposes a support system for a novice to draw an illustration easily. The system has the three functions : 1) A freehand drawn curve which has extra fluctuations is revised into a smooth curve; 2) Partial modification can be made by the following method : one or more modification candidate curves are input and a part of the former curve is revised with one of the modification candidate curves that is chosen by the user; and 3) Two curves are connected smoothly with the rest of the former curve keeping each form as much as possible. The experimental result showed that the proposed system was effective to novices at drawing.
  The Institute of Electronics, Information and Communication Engineers, English
  ISSN：0913-5685, CiNii Articles ID：110004078884, CiNii Books ID：AN10013006
• Real-time Rendering of Translucent Large Models　　　　　　　　　　　　　　　
  Masashi Oda; Kei Iwasaki; Saeko Takagi; Fujiichi Yoshimoto
  Journal of the Institute of Image Electronics Engineers of Japan, Volume：35, Number：4, First page：269, Last page：276, 2006
  We present a real-time rendering method of translucent materials such as marble for large 3D models. To render translucent objects, it is necessary to take into account the subsurface scattering of light. However, rendering translucent objects with the subsurface scattering takes long time. In our method, virtual points are set around the object uniformly. The intensities of the subsurface scattering of light are calculated at each virtual point. The intensities of points that represent the translucent object are interpolated by the intensities of the virtual points. Our method can render about 2,000,000 points with the subsurface scattering in real-time. © 2006, The Institute of Image Electronics Engineers of Japan. All rights reserved.
  English
  DOI：https://doi.org/10.11371/iieej.35.269
  DOI ID：10.11371/iieej.35.269, ISSN：1348-0316, J-Global ID：200902218049322817, SCOPUS ID：85024718415
• Point‐based Rendering of Water Surfaces with Splashes Simulated by Particle‐based Simulation　　　　　　　　　　　　　　　
  小野佳織; 岩崎慶; 土橋宜典; 西田友是
  画像電子学会研究会講演予稿, Volume：222nd, First page：57, Last page：64, 18 Nov. 2005
  Japanese
  ISSN：0285-3957, J-Global ID：200902241203694880, CiNii Articles ID：40007063586, CiNii Books ID：AN00348041
• Particle‐Based Fluid Simulation on the GPU　　　　　　　　　　　　　　　
  岩崎慶; 師芳卓; 土橋宜典; 西田友是
  情報処理学会研究報告, Volume：2005, Number：116(CG-121), First page：121, Last page：126, 18 Nov. 2005
  Japanese
  ISSN：0919-6072, J-Global ID：200902253194342460
• 点で表現された水面によるコースティクスの高速表示法　　　　　　　　　　　　　　　
  岩崎慶; 吉本富士市; 土橋宜典; 西田友是
  Visual Computing グラフィクスとCAD合同シンポジウム予稿集, Volume：2005, First page：117, Last page：122, 16 Jun. 2005
  Japanese
  DOI：https://doi.org/10.11371/aiieej.33vc.0.117.0
  DOI ID：10.11371/aiieej.33vc.0.117.0, J-Global ID：200902200162584759
• 初心者のための手軽なイラスト作成支援システム　　　　　　　　　　　　　　　
  大原寿規; 高木佐恵子; 岩崎慶; 吉本富士市
  Visual Computing グラフィクスとCAD合同シンポジウム予稿集, Volume：2005, First page：185, Last page：190, 16 Jun. 2005
  Japanese
  DOI：https://doi.org/10.11371/aiieej.33vc.0.185.0
  DOI ID：10.11371/aiieej.33vc.0.185.0, J-Global ID：200902265939197171
• Visualization of Users’ Behavior in 3D Virtual Worlds　　　　　　　　　　　　　　　
  中野雄介; 塚田晃司; 高木佐恵子; 岩崎慶; 吉本富士市
  情報処理学会研究報告, Volume：2005, Number：49(GN-56), First page：49, Last page：54, 26 May 2005
  Following high popularity of online games played by a great many people together, it has becoming an important issue to evaluate effectiveness of virtual worlds. There are mainly two methods to evaluate: 1) surveying a questionnaires filled by users, 2) utilization of behavioral measures obtained from the observation of users' behavior. Although the former method is simple, it has a possibility of distortion of data. The latter has less distortion, but data is huge and should be summarized. In this paper, we describe a visualization method of users' behavior in 3D virtual worlds generated by communication tool InCom. Especially, we present a method to gain InCom users' behavioral measures that summarize users' operation logs generated by InCom and make images of the summary. The method allowed us to find several characteristic users' behavior patterns in 3D virtual worlds.
  Information Processing Society of Japan (IPSJ), Japanese
  ISSN：0919-6072, J-Global ID：200902275219158824, CiNii Articles ID：110002695961, CiNii Books ID：AA1155524X
• A Support System for Beginner’s Illustration Using a PDA　　　　　　　　　　　　　　　
  大原寿規; 岩崎慶; 高木佐恵子; 吉本富士市
  画像電子学会研究会講演予稿, Volume：216th, First page：47, Last page：54, 01 Mar. 2005
  Japanese
  ISSN：0285-3957, J-Global ID：200902254586519720, CiNii Articles ID：40006681564, CiNii Books ID：AN00348041
• Fast Calculation Method of Subsurface Scattering　　　　　　　　　　　　　　　
  小田正志; 岩崎慶; 高木佐恵子; 吉本富士市
  画像電子学会研究会講演予稿, Volume：216th, First page：41, Last page：46, 01 Mar. 2005
  Japanese
  ISSN：0285-3957, J-Global ID：200902298543840328, CiNii Articles ID：40006681563, CiNii Books ID：AN00348041
• An Image Retrieval System of Flowers and Evaluation of its Retrieval Methods　　　　　　　　　　　　　　　
  TABATA Soutarou; IWASAKI Kei; TAKAGI Saeko; YOSHIMOTO Fujiichi
  Technical report of IEICE. PRMU, Volume：104, Number：670, First page：1, Last page：6, 25 Feb. 2005
  Although there are many information retrieval systems, few systems can be used in mobile environments. In this paper, we describe an image retrieval system of flowers that can be used easily in mobile environments. Using a mobile phone, we transmit a flower image, simple characteristics of the flower and its positional data to an image retrieval server, and we confirm the result of retrieval using the mobile phone. For retrieval, we considered and evaluated two methods : (1) a ranking method using the sum of the values of characteristics, and (2) a ranking method using the rank of each characteristic. As a result, the highest percentages are 89% for the former and 87% for the latter that were gotten in the cases of the best combination of characteristics weights.
  The Institute of Electronics, Information and Communication Engineers, Japanese
  ISSN：0913-5685, CiNii Articles ID：110003275715, CiNii Books ID：AN10091225
• An Image Retrieval System of Flowers and Evaluation of its Retrieval Methods　　　　　　　　　　　　　　　
  田畑惣太郎; 岩崎慶; 高木佐恵子; 吉本富士市
  電子情報通信学会技術研究報告, Volume：104, Number：668(NLC2004 116-129), First page：1, Last page：6, 18 Feb. 2005
  Japanese
  ISSN：0913-5685, J-Global ID：200902248581598886
• A SUPPORT SYSTEM FOR GENERATING HAND-DRAWN-LIKE CURVES　　　　　　　　　　　　　　　
  MORIMOTO Takayuki; MORI Hirotoshi; IWASAKI Kei; TAKAGI Saeko; YOSHIMOTO Fujiichi
  IWAIT2005, Volume：104, Number：545, First page：143, Last page：148, 04 Jan. 2005
  It is not easy for beginners to draw high quality pictures. If computers translate beginner's unskillful pictures into high quality ones, we are happy in many cases. In this paper, we propose a support system that modifies an unskillful curve drawn by a beginner in drawing into a skillful curve using features of a curve drawn by an expert in drawing. The modified curve preserves fundamental impression of the beginner's curve while having features of the expert's curve. Using a prototype of our system, we experimented to generate skillful hand-drawn-like curves. As a result, those curves having the features of the general forms of beginner's curves and the features of expert's curves were generated.
  The Institute of Electronics, Information and Communication Engineers, English
  ISSN：0913-5685, CiNii Articles ID：110003205409, CiNii Books ID：AN10013006
• Modification Technique of 3D Facial Models for Improving Beauty　　　　　　　　　　　　　　　
  高木佐恵子; 岡田陽介; 岩崎慶; 吉本富士市
  芸術科学会論文誌(Web), Volume：4, Number：4, First page：135-144 (J-STAGE), Last page：144, 2005
  English
  DOI：https://doi.org/10.3756/artsci.4.135
  DOI ID：10.3756/artsci.4.135, ISSN：1347-2267, J-Global ID：200902200802273445, CiNii Articles ID：80020697692
• Implementation and Evaluation of Support System for Informal Communication 3D Virtual World　　　　　　　　　　　　　　　
  中野 雄介; 塚田 晃司; 高木 佐恵子; 岩崎 慶; 吉本 富士市
  ワークショップ2004 （GN Workshop 2004) 論文集, Volume：2004, Number：2004, First page：27, Last page：32, 04 Nov. 2004
  Japanese
  CiNii Articles ID：170000082107
• 携帯電話を用いた花の情報検索システム　　　　　　　　　　　　　　　
  原幸司; 田畑惣太郎; 岩崎慶; 高木佐恵子; 吉本富士市
  情報科学技術フォーラム, Volume：FIT 2004, Number：3, First page：97, Last page：100, 20 Aug. 2004
  Forum on Information Technology, Japanese
  J-Global ID：200902241148263026, CiNii Articles ID：110007683940, CiNii Books ID：AA11740605
• 特異値分解を用いた空の色の高速表示法　　　　　　　　　　　　　　　
  柳田哲一; 岩崎慶; 土橋宜典; 西田友是
  情報処理学会全国大会講演論文集, Volume：66th, Number：4, First page：4.181-4.182, 09 Mar. 2004
  Japanese
  J-Global ID：200902207558400370
• 表面の流れを考慮した石鹸泡のシミュレーション　　　　　　　　　　　　　　　
  天羽賢一; 松沢敬一; 宮崎玲; 岩崎慶; 西田友是
  情報処理学会全国大会講演論文集, Volume：66th, Number：4, First page：4.207-4.208, 09 Mar. 2004
  Japanese
  J-Global ID：200902261419200018
• 特異値分解を用いた空の色の高速表示法　　　　　　　　　　　　　　　
  柳田 哲一; 岩崎 慶; 土橋 宜典; 西田 友是
  Volume：2004, Number：1, First page：179, Last page：180, 09 Mar. 2004
  Japanese
  CiNii Articles ID：170000169849
• “A Calculation of Multiple Scattering Using Scattering Maps and an Efficient Method for Rendering Sky”　　　　　　　　　　　　　　　
  Kei Iwasaki; Tetsuichi Yanagita; Tomoyuki Nishita; Yoshinori Dobashi
  Journal of the Institute of Image Electronics Engineers of Japan, Volume：33, Number：3, First page：515, Last page：522, 2004
  The sky color is indispensable for the display of natural scenes in computer graphics. To render the photorealistic images of the sky, the calculation taking into account multiple scattering is necessary. However the calculation is so complex that enormous computational cost is required. Therefore, in this paper, we proposed a method using virtual shells (sampling shells) generated in the atmosphere. In the method, the illumination distribution of the scattering of light on the virtual shells is considered as a texture map called scattering maps. This makes it possible to calculate the sky color effeciently by using graphics hardware. Furthermore, we also propose a calculation and rendering method using the singular value decomposition to display the sky quickly with a little memory when the height of the viewpoint and the sun altitude change. © 2004, The Institute of Image Electronics Engineers of Japan. All rights reserved.
  English
  DOI：https://doi.org/10.11371/iieej.33.515
  DOI ID：10.11371/iieej.33.515, ISSN：1348-0316, J-Global ID：200902287949030333, SCOPUS ID：33645063278
• 干渉光を考慮した変形する石鹸泡の高速なレンダリング手法　　　　　　　　　　　　　　　
  松沢敬一; 天羽賢一; 岩崎慶; 西田友是
  Visual Computing グラフィクスとCAD合同シンポジウム予稿集, Volume：2003, First page：93, Last page：98, 19 Jun. 2003
  Japanese
  DOI：https://doi.org/10.11371/aiieej.31vc.0.93.0
  DOI ID：10.11371/aiieej.31vc.0.93.0, J-Global ID：200902261436662076
• 水面波における反射屈折によるコースティクスの高速表示法　　　　　　　　　　　　　　　
  岩崎慶; 土橋宜典; 西田友是
  Visual Computing グラフィクスとCAD合同シンポジウム予稿集, Volume：2003, First page：207, Last page：212, 19 Jun. 2003
  Japanese
  DOI：https://doi.org/10.11371/aiieej.31vc.0.207.0
  DOI ID：10.11371/aiieej.31vc.0.207.0, J-Global ID：200902257449268132
• 散乱マップを用いて多重散乱を考慮した天空光の高速表示　　　　　　　　　　　　　　　
  柳田 哲一; 岩崎 慶; 土橋 宜典; 西田 友是
  Volume：2003, Number：1, First page：109, Last page：110, 25 Mar. 2003
  Japanese
  CiNii Articles ID：170000168877
• A Fast Method for Rendering Caustics on Objects within Water Taking into Account Refraction at the Water Surface　　　　　　　　　　　　　　　
  IWASAKI Kei; DOBASHI Yoshinori; NISHITA Tomoyuki
  IPSJ SIG Notes, Volume：109, Number：109, First page：41, Last page：46, 22 Nov. 2002
  Caustics pattern is the light effect caused by the divergence and convergence of the light. Several methods have been developed to render caustics. However calculating caustics is quite complex and therefore it is time consuming. Recently. graphics hardware has made significant progress in the performance. This fact encourages researchers to research the acceleration of realistic image synthesis. We present a fast method for rendering caustics on objects within water by using graphics hardware. To render objects within water viewed from above the water surface, caustics on objects and refraction at the water surface must be taken into consideration. In the proposed method, virtual planes are set around objects. We calculate the intensities of caustics on objects by using virtual planes and store the intensities as textures. Finally, we take into account the refraction at the water surface by using refraction mapping.
  Information Processing Society of Japan (IPSJ), Japanese
  ISSN：0919-6072, CiNii Articles ID：110002780577, CiNii Books ID：AN10100541
• グラフィクスハードウェアを用いた水面波によるcausticsの高速表示法　　　　　　　　　　　　　　　
  岩崎慶; 土橋宣典; 西田友是
  情報処理学会全国大会講演論文集, Volume：64th, Number：4, First page：4.45-4.46, 12 Mar. 2002
  Japanese
  J-Global ID：200902168536054766
• A Method of Fast Rendering of Water and Shafts of Light using Graphics Hardware.　　　　　　　　　　　　　　　
  岩崎慶; 土橋宜典; 西田友是
  情報処理, Volume：42, Number：9, First page：41, Last page：44, Sep. 2001
  Japanese
  ISSN：0447-8053, J-Global ID：200902133180822102
• グラフィックスハードウェアを用いた水面下における物体上のcausticsの表示法　　　　　　　　　　　　　　　
  岩崎慶; 土橋宜典; 西田友是
  Visual Computing グラフィクスとCAD合同シンポジウム予稿集, Volume：2001, First page：19, Last page：24, 21 Jun. 2001
  Japanese
  J-Global ID：200902183729340226
• 多重散乱光を考慮した海面の表示法　　　　　　　　　　　　　　　
  岩崎慶; 西田友是
  情報処理学会全国大会講演論文集, Volume：61st, Number：4, First page：4.73-4.74, 03 Oct. 2000
  Japanese
  J-Global ID：201202151008864077

• 質感科学ハンドブック = Handbook of shitsukan science　　　　　　　　　　　　　　　
  小松, 英彦; 富永, 昌二; 西田, 眞也, [Joint work]
  Jan. 2025
  Japanese, Total pages：xv, 389p, 図版6p (ページ付なし)
  CiNii Books：http://ci.nii.ac.jp/ncid/BD10130529
  ISBN：9784130603256, CiNii Books ID：BD10130529
• コンピュータグラフィックス　　　　　　　　　　　　　　　
  伊藤, 裕之
  Mar. 2015
  Japanese, Total pages：443p
  CiNii Books：http://ci.nii.ac.jp/ncid/BB1832415X
  ISBN：9784903474496, CiNii Books ID：BB1832415X
• Computer Graphics Gems JP 2012 -コンピュータグラフィックス技術の最前線-　　　　　　　　　　　　　　　
  三谷 純; 五十嵐 悠紀; 岩崎 慶; 徳吉 雄介; 吉澤 信; 高山 健志; 岡部 誠; 向井 智彦; 山本 醍田; 梅谷 信行; 安東 遼一; 原田 隆宏, [Contributor]
  2012

• A Study for Designing Crystal in Computer Graphics　　　　　　　　　　　　　　　
  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), Apr. 2023 - Mar. 2027
  Hosei University, Coinvestigator
  Grant amount(Total)：18720000, Direct funding：14400000, Indirect funding：4320000
  Grant number：23H03514
  論文ID：49859577
• 計測スペクトラルBRDFの解析・編集・推定による高精細な質感表現　　　　　　　　　　　　　　　
  Apr. 2021 - Mar. 2025
  Principal investigator
  Grant amount(Total)：17030000, Direct funding：13100000, Indirect funding：3930000
  Grant number：21H03571
  論文ID：49859577
• コンピュータグラフィクスによる質感表現の深化　　　　　　　　　　　　　　　
  Sep. 2021 - Mar. 2023
  Principal investigator
  Grant amount(Total)：7800000, Direct funding：6000000, Indirect funding：1800000
  Grant number：21H05826
  論文ID：49859577
• Development of high fidelity, parameter tuning-free rendering method with error estimation　　　　　　　　　　　　　　　
  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), Apr. 2018 - Mar. 2021
  Iwasaki Kei, Wakayama University, Principal investigator
  Grant amount(Total)：17160000, Direct funding：13200000, Indirect funding：3960000
  Design softwares used for manufacturing require efficient and realistic CG rendering techniques. Although several methods have been proposed for this purpose, most of them rely on heuristic assumptions. This incurs users on tedious parameter tunings to obtain rendering results with desired accuracies. This research project aims to develop a rendering method that can estimate the error accurately and control the error, which can eliminate the tedious parameter tunings from the users. Our method only requires two intuitive parameters and can render the results with desired accuracy.
  Grant number：18H03348
  論文ID：32561691
• Modeling and Rendering of Appearances of Complex Objects by Computer Graphics Techniques　　　　　　　　　　　　　　　
  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area), Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area), 29 Jun. 2015 - 31 Mar. 2020
  Yoshinori Dobashi, Hokkaido University
  Grant amount(Total)：49140000, Direct funding：37800000, Indirect funding：11340000
  This research project aimed at achieving the following three research goals. They are reproduction of realistic object appearances, investigation of important factors to reproduce the realistic appearances, and development of methods that allows the user to edit the appearances. We have developed a series of methods to address related problems. Examples include modeling complex natural objects using micro CT, error estimation framework for intensity calculation of virtual objects, efficient rendering of translucent materials, appearance analysis of illustrations, inverse appearance problems, realistic reproduction of fluid media. Our achievements have been published in the top journals in computer graphics field.
  Grant number：15H05924
  論文ID：48505728
• 写真を用いた雲のモデリング 研究課題　　　　　　　　　　　　　　　
  Apr. 2016 - Mar. 2019
  Principal investigator
  Grant amount(Total)：338000, Direct funding：260000, Indirect funding：78000
  Competitive research funding
• マルチスケールマテリアルの質感編集および質感パラメータの計算に関する研究　　　　　　　　　　　　　　　
  Apr. 2013 - Mar. 2015
  Principal investigator
  Grant amount(Total)：10010000, Direct funding：7700000, Indirect funding：2310000
  Grant number：25135724
• Real-time Rendering of Dynamic Scenes with All-frequency Lighting and BRDF　　　　　　　　　　　　　　　
  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Young Scientists (B), Apr. 2012 - Mar. 2015
  IWASAKI Kei, Wakayama University, Principal investigator
  Grant amount(Total)：4160000, Direct funding：3200000, Indirect funding：960000
  We propose a real-time rendering method for dynamic scenes under all-frequency environmental lighting. To render the object surfaces illuminated by distant environmental lighting, our method represents the environmental lighting and the BRDFs with spherical Gaussians and represents the visibility functions with spherical signed distance functions (SSDFs). Although these representations enable us to render scenes under all-frequency lighting in real-time, the previous method is limited to static scenes since the computational costs of SSDFs are quite high. To address this problem, we propose an efficient calculation method of SSDFs by approximating the object geometries with a set of spheres. Moreover, to accelerate the SSDF calculation, our method employs the hierarchical representation of spheres. This makes it possible to render fully dynamic scenes where the viewpoints, lighting, and BRDFs can be changed at run-time and objects can move, rotate and be deformed in real-time.
  Grant number：24700093
• Efficient and realistic rendering of dynamic scenes with dynamic BRDFs　　　　　　　　　　　　　　　
  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Young Scientists (B), Apr. 2009 - Mar. 2011
  IWASAKI Kei, Wakayama University, Principal investigator
  Grant amount(Total)：3510000, Direct funding：2700000, Indirect funding：810000
  We have proposed an efficient and realistic rendering method for applications of lighting and material designs. For such applications, designers change the viewpoints, lighting, BRDFs and the positions of objects. Moreover, interactive rendering is required to design efficiently. To meet these requirements, we propose an efficient rendering method for dynamic scenes where the viewpoints, lighting, BRDFs, and the positions of objects can be changed at run time, taking into account captured lighting and BRDFs.
  Competitive research funding, Grant number：21700112
• A Study on Fast, High-quality Synthesis of CG Images　　　　　　　　　　　　　　　
  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (C), 2008 - 2011
  DOBASHI Yoshinori; IWASAKI Kei, Hokkaido University
  Grant amount(Total)：4420000, Direct funding：3400000, Indirect funding：1020000
  We developed fast methods for the generating synthetic images of gaseous objects and deformable objects. These objects have been difficult to be handled and it took about several minutes to create an image of these objects. Our method creates a database in a preprocessing step to accelerate the image generation process. The proposed method made it possible to generate an image within 100 milliseconds.
  Grant number：20500082
• Fast, Realistic Rendering of Dynamic Scenes with Global Illumination　　　　　　　　　　　　　　　
  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Young Scientists (B), Apr. 2007 - Mar. 2009
  IWASAKI Kei, Wakayama University, Principal investigator
  Grant amount(Total)：3000000, Direct funding：2700000, Indirect funding：300000
  Competitive research funding, Grant number：19700095
• 透明物体の光学的特性および照明効果を考慮したリアルタイムレンダリング手法の研究　　　　　　　　　　　　　　　
  Apr. 2005 - Mar. 2006
  Principal investigator
  Grant amount(Total)：3000000
  Competitive research funding, Grant number：17700114
• Research on a support system for generating comfortable hand-drawn like curves　　　　　　　　　　　　　　　
  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (C), 2003 - 2005
  YOSHIMOTO Fujiichi; HARADA Toshinobu; TAKAGI Saeko; IWASAKI Kei, Wakayama University
  Grant amount(Total)：3700000, Direct funding：3700000
  In this research project, we have investigated a beginner's support system for generating a comfortable hand-drawn like curve, and its related research areas. The outline of the results is as follows.
  It is not easy for beginners to draw high quality pictures. If computers modify beginner's unskillful pictures into high quality ones, we are happy in many cases. To this end, we consider to use the features of pictures drawn by experts in drawing. We have proposed a support system that modifies an unskillful curve drawn by a beginner in drawing into a high quality one using the features of curves drawn by an expert in drawing. The modified curve preserved impression of the beginner's curve while having features of the expert's curve. Moreover, we have proposed a method to treat not only the general form (skeleton line) but also the strength of the silhouette line. Using a prototype system of the method, we experimented whether high quality hand-drawn-like silhouette lines (with strengths) were made. As a result, we confirmed that our method was effective in making those silhouette lines.
  As the related works of the above main research, we have done following five themes.
  1.Development of a handy system to support novices' illustrations
  2.Study on key-line curves of faces using curvature analysis and FFT
  3.Evaluation of impression for automobile configuration using VR system
  4.Analysis of the curves of Japanese swords
  5.Optimization of information design in car navigation considering drivers' sense of value
  Grant number：15500068