Takami Yasuda

An Origami Playing Simulator in the Virtual Space

SUMMARY A virtual manipulation system for origami (paper folding) is described. A piece of paper defined in a computer can be deformed interactively by picking and moving a corner vertex of a paper face on a graphic screen using a mouse. Three kinds of folding operations and a curving operation transform the paper into a three-dimensional figure made of flat or curved surfaces. The roundness of the curved surfaces is calculated in real-time by minimizing an elastic energy function. The simulated paper has traditional Japanese decoration applied as a texture to give a more realistic appearance. It is rendered with shading in real-time.

Computer system for craniofacial surgical planning based on CT images

A system for craniofacial surgical planning utilizing stacks of 2-D tomographic images is described. The four parts of the system are image generation, 2-D surgical planning, 3-D plan confirmation, and rough prediction of face shape after an operation. The four parts are combined to provide a useful surgical planning system. Because a gradient shading technique is used for generating 3-D images, the bumpy shape of the voxel (volume element for 3-D objects) sometimes obscures the essential shape of the displayed objects. To smooth undesirable bumps without losing the essential object shape, 2-D filtering is applied. Arbitrary bone blocks can be specified and moved interactively with a graphic terminal to any derived location to aid surgical planning. The chosen plan can be confirmed by observing computer-generated 3-D images from arbitrary directions since the process necessary to generate a 3-D image for any one direction should be adequate for all directions. Postoperative face-shape prediction is available for evaluating the operation plan at the last stage of the planning sequence.

A shading model for cloth objects

A fundamental light reflection model that takes into account the internal structure of cloth to render the peculiar gloss of cloth objects is presented. In developing this model, the microscopic structure of textiles was considered. The model represents fabric features such as fibers cross-sectional shape or weave. By measuring the reflected light intensity from actual cloth objects of several typical materials, it was verified that the model can express the properties of several kinds of cloth, and the parameters in the model were defined.<<ETX>>

A Generation Model for Human Skin Texture

This paper describes a generation model of human skin with Computer Graphics. On the basis of the fact that the human skin surface is of fine structure consisting of furrows and ridges, we have established and implemented a geometric model for expressing these features, using hierarchical Voronoi-division process for tile texture pattern, a Bezier cubic curve segment for curved surfaces of ridges, a pseudo-fractal subdivision algorithm for natural fluctuation, and so on. Furthermore, we refer to our own approach to the reflection model and apply our skin-texture generation method to the texture of other objects such as leather from reptile skin.

Automatic composition and simulation system for ballet sequences

We have developed an automatic composition system for ballet choreographies by using 3DCG animation. Our goal is to develop useful tools in dance education such as a creation-support system for ballet teachers and a self-study system for students. The algorithm for automatic composition was integrated to create utilitarian choreographies. As a result of an evaluation test, we verified that the created choreographies had a possibility to be used in the actual lessons. This system is valuable for online virtual dance experimentation and exploration by teachers and choreographers involved in creative practices, improvisation, creative movement, or dance composition.

A distributed multiuser virtual space system

Today, in an era of increased Internet use, tools designed to help users communicate across the network have begun to proliferate. Interest in virtual 3D spaces is growing too. We outline a technique for directly transferring the necessary parameter information to express virtual human emotions across a network. We also discuss the methods required for constructing a system that can facilitate this kind of direct transfer using distributed object technology. We offer a method for integrating the services of our system and a constructed database of movements. Finally, we propose various quality-of-service (QoS) techniques for effective motion information transfer in our constructed system.

A simulation system for craniofacial surgeries based on 3D image processing

A practical simulation system based on analysis of clinical surgical procedures is described. The system provides fundamental manipulation operations to simulate actual surgical activities. There is a simulated cutting operation for sectioning a bone into various arbitrary shapes, a movement operation to transport a bone block to a desired position, and a restricted-movement operation to move a bone block until it comes into contact with other bone. The system also generates a skin surface image of a postoperative patient based on a simulated plan of bone manipulation. An operational system to enable physicians handling the system to work at ease has been devised. The structure and function of the system are described, and examples of its use in simulation are given.<<ETX>>

A Three-Dimensional Display System Of Ct Images For Surgical Planning

This paper presents a system for display-ing three-dimensional images of human brain structure by reconstructing them from CT image sequences. Functions of the system include : reslicing (pro-ducing cross-sectional images along an arbitrary plane); generation of 3D shaded surfaces of the skull, ventricle and disease lesions (hematoma and tumor etc.), windowing, and translucent display of the skull. All these functions can be combined in an arbitrary way to generate complicated 3D images. The system is expected to be useful especially for surgical planning and education in medicine.

LiNeS: Virtual Network Environment for Network Administrator Education

User-mode Linux (UML) is virtual environment software being developed for server integration, testing buggy software, and so on. However, we have been applying UML to network administrator education, since it has functions for comprising networks. The Linux Network Simulator (LiNeS) is a system that provides an environment for various network training based on virtual networks realized by UML on one PC. Since LiNeS does not require many network machines, unlike conventional network training, we believe that it can become a new learning method in network administrator education.

Development of a planisphere type astronomy education web system based on a constellation database using ajax

In this study, we build a knowledge database that consists of topics planetarium curators have about astronomy and the stars. We suggest that the database should have a structure based on constellations and that mirrors the basic way in which humans perceive the night sky. Furthermore, we developed a web system for astronomy education using Ajax. The web system’s interface is based on the planisphere, which is most basic tool for finding stars.