Optimized Butterfly-based lifting scheme for semi-regular meshes

In this paper, we propose an optimization of the lifted Butterfly scheme for semi-regular meshes. This optimization consists in adapting prediction and update steps at each level of resolution for a given semi-regular mesh. The motivation is the improvement of the multiresolution analysis in order to increase the compression performances of the subsequent geometry coder. We first compute an optimized prediction filter that minimizes the L1-norm of the wavelet coefficients for each level of resolution, independently. We then compute the update filter in order to preserve the data average (0^th moment) at the lower resolution. Experimental results show that our technique globally reduces the entropy of the wavelet coefficients of any semi-regular mesh. Consequently our contribution also improves the compression performances of the zerotree coder PGC.