Permuting and lifting wavelet coding for structured 3-D geometry data with expanded nodes

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.