Progressive Lower Trees of Wavelet Coefficients: Efficient Spatial and SNR Scalable Coding of 3D Models

We perform an in-depth analysis of current state-of-the-art waveletbased 3D model coding techniques and then present a new one that outperforms them in terms of compression efficiency and, more importantly, provides full spatial and SNR scalability: PLTW (Progressive Lower Tree Wavelet) coding. As all SNR scalable bit-streams, ours can be used in heterogeneous networks with a wide range of terminals, both in terms of processing power and bandwidth. But because of being spatially scalable, the PLTW bit-stream does not impose on the less powerful terminals the need of building detail trees as deep as required by the maximum LOD, because the wavelet coefficients are sent on a per-LOD basis, thus achieving a “local” SNR scalability within a “global” spatial scalability. In particular, we show that our technique provides a substantial advantage over the only similar one in a current ISO standard (MPEG-4), and thus suggest that PLTW be considered for its future versions.