Payan Frédéric, Antonini Marc
Laboratoire I3S, UMR 6070 CNRS, Université de Nice-Sophia Antipolis, France.
IEEE Trans Vis Comput Graph. 2006 Jul-Aug;12(4):649-57. doi: 10.1109/TVCG.2006.73.
The objective of this paper is to propose an efficient model-based bit allocation process optimizing the performances of a wavelet coder for semiregular meshes. More precisely, this process should compute the best quantizers for the wavelet coefficient subbands that minimize the reconstructed mean square error for one specific target bitrate. In order to design a fast and low complex allocation process, we propose an approximation of the reconstructed mean square error relative to the coding of semiregular mesh geometry. This error is expressed directly from the quantization errors of each coefficient subband. For that purpose, we have to take into account the influence of the wavelet filters on the quantized coefficients. Furthermore, we propose a specific approximation for wavelet transforms based on lifting schemes. Experimentally, we show that, in comparison with a "naive" approximation (depending on the subband levels), using the proposed approximation as distortion criterion during the model-based allocation process improves the performances of a wavelet-based coder for any model, any bitrate, and any lifting scheme.
本文的目的是提出一种基于模型的高效比特分配过程，以优化用于半规则网格的小波编码器的性能。更确切地说，该过程应计算小波系数子带的最佳量化器，以使针对一个特定目标比特率的重构均方误差最小化。为了设计一个快速且低复杂度的分配过程，我们提出一种相对于半规则网格几何编码的重构均方误差的近似方法。该误差直接由每个系数子带的量化误差表示。为此，我们必须考虑小波滤波器对量化系数的影响。此外，我们提出一种基于提升方案的小波变换的特定近似方法。通过实验，我们表明，与“简单”近似方法（取决于子带级别）相比，在基于模型的分配过程中使用所提出的近似方法作为失真准则，可提高任何模型、任何比特率和任何提升方案的基于小波的编码器的性能。
