2012年度

2012 Fiscal Year

Domestic Academic Journals (in Japanese)

Satoshi Nakajima, Issei Fujishiro
Interactive simulation of whirlwind using grid and particles
in The Journal of the Society for Art and Science, Vol. 11, No. 4, pp. 157-165, December 2012
In this paper, we present an interactive approach to visual simulation of whirlwind using grid and particles. Higher-resolution simulation can be carried out efficiently by perturbing air flow computed on a rough grid with small-scale turbulence. The grid-based simulation first provides a primary whirlwind flow field through modeling its underlying heat convection. Then, the particle-based simulation computes the transport energy of turbulence based on a two-equation k-ε model, which allows us to capture the turbulence details. The dynamism of whirlwind is conveyed effectively by the interaction with rigid and deformable bodies, such as flag, branch and paper, placed on interactively-controllable trajectories. In addition, a simplified variant of particle-based volume rendering is utilized to delineate changes in the translucency of whirlwind, which reflects the amount of sand particles stirred up from the ground.

Ayaka Nakatani, Issei Fujishiro, Hiroyo Ishikawa, Hideo Saito
Resource-Aware Rendering for Laser Plasma Scanning 3D Display Devices Using Surface Descriptors
in Transactions of the Virtual Reality Society of Japan, Vol. 17, No. 4, pp. 419-428,December 2012
Laser-Plasma Scanning 3D Display (LPSD) is one of the most advanced volume scanning display devices, and plots a unicursal series of illuminants freely in the air. Though the LPSD device has been repeatedly upgraded, even the latest version is only capable of plotting an object at a rate of 5,000 illuminants per second, purely due to the hardware limitation. If we plotted illuminants at a regular interval with a constant brightness, it might possibly lead to loss of geometry and/or surface texture of the displayed object. This paper, therefore, proposes a software-based approach to ameliorate this problem, which controls the brightness and density of plotted illuminants in accordance with existing surface descriptors, to convey salient features of 3D shapes with even a limited number of illuminants.

International Conference (Peer-Reviewed)

Kazuhide Ueda, Issei Fujishiro
Visual simulation of bleeding on skin surfaces taking physisorption and congelation into primary account
in Proceedings of Computer Graphics International 2012, Bournemouth (England), June 2012
The liquid dynamics has a significant impact on video works, and bleeding is no exception. Hemorrhage scenes possess highly-important implications, as seen from the fact that they might make the work rated age limit. Lack of visual reality in those scenes would reduce the overall quality of the work. Against this background, we have built upon a commonly-used Lagrangian method, called SPH (Smoothed Particle Hydrodynamics), to simulate bleeding on skin surfaces more faithfully. Remarkable features of the extension are three-fold: (1) bleeding from a wound modeled along with in-vivo blood flow, which takes account of the wound’s shape, hemorrhage volume, and bleed momentum; (2) physisorption of blood on the skin surfaces formulated by introducing an additional adsorption term, analogous to van derWaals force, to the original Navier-Stokes equations and by allowing for saturation of adsorption media; and (3) congelation of blood represented by varying viscosity according to the time exposed to the air.

Satoshi Nakajima, Issei Fujishiro
Visual simulation of whirlwind using a grid and particles
in Proceedings of NICOGRAPH International 2012, pp. 27-34, Bali (Indonesia), July 2012
In this paper, we present an interactive approach to visual simulation of whirlwind using a grid and particles. High-resolution simulation can be carried out efficiently by perturbing air flow computed on a rough grid with small-scale turbulence. The grid-based simulation first provides a primary whirlwind flow field through modeling its underlying heat convection. Then, the particle-based simulation computes the transport energy of turbulence based on a two-equation k-ipsilon model, which allows us to capture the turbulence details. The dynamism of whirlwind is conveyed effectively by the interaction with rigid and deformable bodies, such as flag, branch and paper, placed on interactively-controllable trajectories. In addition, a simplified variant of particle-based volume rendering is utilized to delineate changes in the translucency of whirlwind, which reflects the amount of sand particles stirred up from the ground.

Ken Nagao, Issei Fujishiro
Making digital signage adaptive through a genetic algorithm – Utilizing viewers’ involuntary behaviors –
in Proceedings of the International Conference on Computer Vision Theory and Applications 2013, Vol. 2, pp. 54-59, Barcelona (Spain), February 2013
Digital signage has been becoming more popular due to the recent development of underlying hardware technology and improvement in installing environments. In digital signage, it is important to make the content more attractive to the viewers by evaluating its current attractiveness on the fly, in order to deliver the message from the sender more effectively. Most previous works for this evaluation do not take the viewers’ feeling towards the content into account, and the content is improved manually if needed in an off-line manner. In this paper, we present a novel method which does not rely on such manual evaluation and automatically makes the content more adapted to the viewers. To this end, we take advantage of the viewers’ involuntary behaviors in front of the digital signage for online updates through the usage of a genetic algorithm.

Yuriko Takeshima, Issei Fujishiro, Shigeo Takahashi, Toshiyuki Hayase
A topologically-enhanced juxtaposition tool for Hybrid Wind Tunnel
in Proceedngs of IEEE Pacific Visualization Symposium 2013, pp. 113-120, Sydney (Australia), February 2013
We have developed a hybrid wind tunnel, where 2D measurementintegrated (MI) simulation, which utilizes actual data acquired from real air flow behind a square cylinder, plays an important role in improving the accuracy of the numerical analysis. The wind tunnel requires an accompanying visual analysis tool with which we can effectively peer into the relationships between the actual and simulated flow fields. In this paper, we attempt to exploit an augmented reality display to that end. The basic idea is to superimpose the computationally-visualized MI simulated pressure field onto the actual flow velocity structure physically-visualized with oil misttraced streaklines instantaneously. Spatial registration of these two visual sources is rather straight-forward since the fixed cylinder of the wind tunnel is easily identified, whereas visualizing the MI simulated pressure field can be characterized with a sophisticated scheme based on differential topology. Considering the fact that vortex centers are located at local minima in the pressure field, and each minimum is surrounded by a derived topological feature called ridge cycle, we can colorize the field adaptively and keep track of Karman vortex streets robustly, regardless of drastic change in the Reynolds number of the flow field.

International Conference Posters (Peer-Reviewed)

Tetsuya Takahashi, Issei Fujishiro
Particle-based simulation of snow trampling taking sintering effect into account
in Proceedings of ACM SIGGRAPH 2011 Posters, No. 3, Los Angeles (America), August 7, 2012

Takanobu Mitani, Issei Fujishiro
CosmicAI: Generating sky backgrounds through content-based search and exible composition
in Proceedings of ACM SIGGRAPH 2011 Posters, No. 52, Los Angeles (America), August 7, 2012
In film and game production, sky images are frequently changed to fit a given situation. SkyFinder [Tao et al. 2009] and A System for Editing Sky Images Using an Image Database (Ono2011 for short hereafter) [Ono et al. 2011] allow the users to generate sky images efficiently without three dimensional computer graphics software such as Vue and Terragen. SkyFinder users specify related attributes (category, layout, horizon height, sun position, and richness) so as to easily search sky images downloaded from Flickr.com. Ono2011 lets the users to take two steps. The first step is to generate a background with atmospherically-distributed sky color through an intuitive user interface. The second step is to compose clouds using a collection of real photographs downloaded from Flicker.com. The detailed user actions are to specify related features (sky color, cloud shape, amount of edges, and sun position); to select clouds in the search results by a paint-like operation; and to compose them into the original background. It looks like the quality of sky images generated by these two systems becomes unstable, because many public photographs are unsuitable for composition.

Oral Presentation

Issei Fujishiro
Managing scalable visualization lifecycle
presented at The Second International Symposium of Center for Simulation Sciences, Ochanomizu University, January 16, 2013

Issei Fujishiro
Condensed views for long-duration visualization provenance
presented at IEEE Pacific VAST 2013, Sydney(Australia), February 26, 2013

Technical Reports

Issei Fujishiro
Optimizing point cloud geometry for 3D aerial display
Microsoft Research CORE7 Project Summary Booklet, pp. 21-23, June 29, 2012