Computer Graphics Laboratory

/ Satoshi Nishimura / Assistant Professor
/ Veronique Martin-Lang / Visiting Researcher

The Computer Graphics Laboratory is currently working on the following research projects:

1. Parallel architecture for polygon rendering and volume visualization Parallel processing is one of the most powerful ways for improving the processing speed of computers. Especially in the area of computer graphics, many researchers have been trying to apply the techniques of parallel processing to various problems. There are three reasons for this research:

• Fast display is desirable for a better user interface.
• Most image generation techniques are too slow without parallel processing.
• Many problems in computer graphics potentially have parallelism.

In the Computer Graphics Laboratory, we have a parallel graphics machine called the VC-1 which was developed by Prof. Nishimura, one of the members of our laboratory. The VC-1 comprises 16 processing elements each of which contains the Intel i860 processor.

One of the current research directions is the extension of the VC-1 architecture so that anti-aliasing is fully supported. We are also planning to add special hardware for rasterization to the VC-1 architecture to improve polygon rendering performance.

Another research direction is to develop a parallel machine for real-time volume rendering. Volume rendering is particularly important in medical applications. We are planning to develop scalable hardware including a special chip for trilinear interpolation and alpha-blending.

2. Surface reconstruction, geometric modeling through shape information

Shape of 3-dimensional objects is a concept of fundamental importance for description, analysis and representation. Our aim is to extract shape information from real data and more precisely from Noh masks in order to develop a shape-based geometric modeling environment. We developed several algorithms of extraction of shape features based on curvature extrema (ridges and ravines) for surfaces defined by height functions. An extension to triangulations is under study. We are currently focusing on reconstruction algorithms from scattered data in order to construct a triangulation of the scanned masks. One method uses the particularities of the scanner whereas the other one is based on the Delaunay triangulation and a boundary extraction algorithm.

We are also involved in a topology-based geometric modeling project. Our study of a geometric modeling environment based on simplicial sets led us to the definition of operations for the manipulation of triangular patches. In particular, we defined a cartesian product of triangular Bezier patches.

Refereed Proceeding Papers

1. Satoshi Nishimura, PMML: A Music Description Language Supporting Algorithmic Representation of Musical Expression. Proceedings of International Computer Music Conference 1998, p.171--174, ICMA, 1998.

Others

1. Satoshi Nishimura, Developed the PMML: A Music Description Language Supporting Software, 1997.

2. Yoshitaka Endo, The Development of the Visual Environment for the Practical Music Macro Language. The University of Aizu, 1997. Thesis Advisor: Satoshi Nishimura.

3. Notoka Katoh, The Simulation of a Parallel Machine for Volume Rendering. The University of Aizu, 1997. Thesis Advisor: Satoshi Nishimura.

4. Tomoaki Sasaki, Music Structure Analysis Based on an Extended Position Tree. The University of Aizu, 1997. Thesis Advisor: Satoshi Nishimura.

5. Atsushi Marui, PMML Animator -- VRML animation using PMML. The University of Aizu, Thesis Advisor: Satoshi Nishimura.

6. Tokuhisa Abe, The Design of a Parallel Rasterization Unit for Polygon Rendering. The University of Aizu, 1997. Thesis Advisor: Satoshi Nishimura.

7. Naoki Oomori, The Organization and Evaluation of a Parallel Volume Rendering System. The University of Aizu, 1997. Thesis Advisor: Satoshi Nishimura.