One promising method for coding 3-D geometry data is based on the structure processing of a 3-D model on triangle lattice planes, while maintaining connectivity. In the structuring process, each vertex may be assigned to several nodes on the triangular lattice planes. One of the nodes to which a vertex is assigned is selected as a representative node and the others are called expanded nodes. Only geometry data of the vertices at the representative nodes are required for reconstructing the 3-D model. The geometry data at the representative nodes are often separated by expanded nodes on the triangular lattice plane. In this paper we apply a lifting wavelet transform with the permuting process for an expanded node at even locations and the neighboring representative node to reduce the correlations among the separated coordinate values in the lower frequency band. Experimental results for the 3-D model with complex connectivity show the proposed scheme gives better coding performance compared to the usual schemes.

This paper presents a new coding method for 3-D geometry data using surface simplification and the wavelet transform. A polygonal mesh model is constructed from the connectivity information and the geometric data. We have previously presented a coding method for the structured geometry data structured on a 2-D lattice plane. In this paper we present a coding method for the structured geometry data including the vertices which were contracted by the surface simplification as extended nodes on the 2-D plane. We apply the shape-adaptive wavelet transform to the structured geometry data containing the extended nodes to obtain the wavelet coefficients. Defining the parent-children dependency of the wavelet coefficients among the different frequency bands in consideration of the extended nodes, we obtain the coded data by using SFQ. Some experiments for a statue showed that the proposed method gives good coding performance compared to TAGC scheme.

In order to develop a system to synthesize arbitrary viewpoint images efficiently, two representative schemes that use the 3-D geometric model to synthesize images have been the focus of attention: model-based rendering and image-based rendering. Image-based rendering is reported to give a better coding performance than the model-based rendering. Although the image-based rendering synthesizes the relatively accurate diffuse reflection component from the camera images at the different viewpoints, it can not synthesize the specular reflection component with sufficient accuracy because the movement of the specular reflection component on the object surface by the viewpoint change is not taken into consideration. Therefore, we propose a method of synthesizing arbitrary viewpoint images by estimating the motion vectors of the specular reflection components for the 3-D model-based synthesized image used as the reference image. Experiments with a carved wooden object show the effectiveness of the proposed method through the coding performance and the subjective evaluation of the synthesized image.

In this paper, we describe a triangular lattice structuring method for 3D polygonal mesh data and a shape-adaptive wavelet transform of the structured geometry and textural data. Efficient representations of a 3D object data has attracted wide attention for transmission and storage of computer graphics data and interactive design in manufacturing. Polygonal mesh data, which consist of connectivity information, geometry data and textural data, are often used for representing a 3D object in many applications. We propose a method for structuring the polygonal mesh data on a triangular lattice plane with expanded nodes. And a shape-adaptive wavelet coding method is applied to the structured geometry data considering the expanded nodes. Experimental results show that the proposed method gives better coding performance than the topologically assisted geometry compression scheme.

Efficient representations of a 3D object shape and its textural data have attracted wide attention for the transmission of computer graphics data and for interactive design in manufacturing. Polygonal mesh data, which consist of connectivity information, geometric data and textural data are often used for representing a 3D object in many applications. We propose a compression method for polygonal mesh data by structuring its geometric and textural data on a triangular lattice with expanded nodes. The structuralized geometric and textural data are compressed using a 2D signal coding method. Experimental results following from the application of the new method to polygonal mesh data show that the proposed scheme performs efficiently.

We propose an adaptive post-processing method for reducing blocking artifacts in block-based video coding. This method is based on DCT coefficient estimation by quadratic programming method for each block. For the blocks including detected edges, we define an objective function on the basis of preservation of the edges and continuity of the pixel values at the block boundaries. For the other blocks, we define an objective function on the basis of the continuity around the block boundaries. Furthermore, the DCT coefficients are estimated sequentially from lower frequency side to higher in order to obtain the stable estimates. For the blocks coded with the use of motion-compensated prediction, we estimate the DCT coefficients representing the prediction errors. The experiments show that the proposed method improves both subjective and objective image quality compared to the H.263 decoded frames and also improves the SNR of the sequences coded by the H.263+ Annex.J method at several bit rates.

Cellular automaton (CA)-based device simulation is one of the most powerful tool to solve Boltzmann transport equation (BTE) of carriers in semiconductor devices. In comparison to the Monte Carlo (MC) method which suffers statistical noise problems, cell representation used in the CA method realizes noise free analysis of the carrier distribution function (DF) both in real and momentum space. However, CA requires more computer resources than MC in typical cases because cell sizes used for both real and momentum space are restricted to be small enough not to cause artificial diffusion (ADF). In this paper, a new scheme for calculation of flux among cells is proposed in which carrier distribution is interpolated between neighbor cells. The suppression of ADF is confirmed through comparisons to other simulation methods in homogeneous cases, an n/sup +/-p diode case and an n/sup +/-n-n/sup +/ structure case. Consistency with MC analysis is also demonstrated by analyzes of homogeneous cases and an n/sup +/-n-n/sup +/ case and also by a theoretical study. A speed up of at least two orders of magnitude can be obtained by introducing the new flux calculation whose accuracy is ensured with much less number of cells than conventional CA methods. Consequently, this CA method is drastically improved as a practical tool for semiconductor device modeling from the point of CPU time and accuracy.