A Region-Based Progressive Coding of Semi-Regular 3-D Meshes for View-Dependent Transmission

We first introduce in this paper a new wavelet based segmentation algorithm for three-dimensional (3-D) Semi-Regular (SR) meshes. This method is then considered as a pre-processing step in a view-dependent progressive coding of 3-D meshes. Our segmentation process aims at producing homogeneous regions which have similar frequency amplitudes on the mesh surface, in other words: patches with different degrees of roughness. As a preliminary step of the development of a locally-based Rate-Distortion (R-D) optimized coding scheme, we propose to study the behaviour of the wavelet decomposition in the created patches, during the coding and the view-dependent reconstruction processes. To our knowledge, no previous work has ever considered the influence of the nonrefined parts of a mesh on the more detailed ones, in a view dependent context. The main contribution of this paper consists in considering three different possible wavelet decompositions, close to the patch borders, and to study their influence during the coding and the view-dependent reconstruction stages. Among these three decompositions, we define a new scheme and finally propose various experimentations to demonstrate that it behaves better than the other classical considerations, for view-dependent reconstruction purposes.