Tomoyuki Nishita

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This paper proposes a simple and computationally inexpensive method for animation of clouds. The cloud evolution is simulated using cellular automaton that simplifies the dynamics of cloud formation. The dynamics are expressed by several simple transition rules and their complex motion can be simulated with a small amount of computation. Realistic images(More)
This paper presents a new algorithm for computing the points at which a ray intersects a rational Bézier surface patch, and also an algorithm for determining if an intersection point lies within a region trimmed by piecewise Bézier curves. Both algorithms are based on a recent innovation known as Bézier clipping, described(More)
Methods to display realistic clouds are proposed. To display realistic images, a precise shading model is required: two components should be considered. One is multiple scattering due to particles in clouds, and the other factor to be considered is sky light. For the former, the calculation of cloud intensities has been assumed to be complex due to strong(More)
The effect of shadows and interreflection created by room obstructions is an important factor in the continuous tone representation of interiors. For indirect illumination, in most cases a uniform ambient light has been considered, even though the interreflection gives very complex effects with the shaded images.The proposed method for indirect lighting(More)
To create realistic images using computer graphics, an important element to consider is atmospheric scattering, that is, the phenomenon by which light is scattered by small particles in the air. This effect is the cause of the light beams produced by spotlights, shafts of light, foggy scenes, the bluish appearance of the earth's atmosphere, and so on. This(More)
Optimal viewpoint selection is an important task because it considerably influences the amount of information contained in the 2D projected images of 3D objects, and thus dominates their first impressions from a psychological point of view. Although several methods have been proposed that calculate the optimal positions of viewpoints especially for 3D(More)
This paper presents a practical approach to the animation of hair at an interactive frame rate. In our approach, we model the hair as a set of particles that serve as sampling points for the volume of the hair, which covers the whole region where hair is present. The dynamics of the hair, including hair-hair interactions, is simulated using the interacting(More)
A method to display the earth as viewed from outer space (or a spaceship) is proposed. The intention of the paper is application to space flight simulators (e.g., reentry to the atmosphere) and the simulation of surveys of the earth (comparisons with observations from weather satellites and weather simulations); it is not for geometric modeling of terrains(More)
This paper presents a method for automatically extracting a scene depth map and the alpha matte of a foreground object by capturing a scene through RGB color filters placed in the camera lens aperture. By dividing the aperture into three regions through which only light in one of the RGB color bands can pass, we can acquir three shifted views of a scene in(More)