Lifting Wavelet Coding with Modified Permutation for 2-D Structured Geometry of Polygonal Mesh

A new coding scheme for geometry data of a polygonal mesh based on a structuring process of a 3-D model on a triangular lattice plane is proposed. A complex connectivity of the polygonal mesh is structured by assigning a vertex of the 3-D model to several nodes of triangular lattice plane with maintaining the connectivity. The geometry data of a vertex are arranged at the position of the representative node which is selected from the nodes to which the vertex is assigned. The structured geometry data with many undefined node points on a triangular lattice plane have to be coded efficiently. In this paper, we present a lifting wavelet based coding scheme for geometry data compression with permutation and coefficient modification process. The permutation process for an expanded node at an even location and the neighboring representative node arranges more representative nodes into the lower frequency band. The modification process uses the modified coefficients obtained from the coefficients of the adjacent representative nodes instead of the original coefficients to restrain increases in the decomposed coefficients with larger magnitude. Experimental results show that the proposed scheme gives better coding performance than usual schemes.