De Vleeschouwer Christophe, Zakhor Avideh
Lab. de Telecommun., Univ. Catholique de Louvain, Belgium.
IEEE Trans Image Process. 2003;12(10):1226-42. doi: 10.1109/TIP.2003.817253.
This paper provides a precise analytical study of the selection and modulus quantization of matching pursuit (MP) coefficients. We demonstrate that an optimal rate-distortion trade-off is achieved by selecting the atoms up to a quality-dependent threshold, and by defining the modulus quantizer in terms of that threshold. In doing so, we take into account quantization error re-injection resulting from inserting the modulus quantizer inside the MP atom computation loop. In-loop quantization not only improves coding performance, but also affects the optimal quantizer design for both uniform and nonuniform quantization. We measure the impact of our work in the context of video coding. For both uniform and nonuniform quantization, the precise understanding of the relation between atom selection and quantization results in significant improvements in terms of coding efficiency. At high bitrates, the proposed nonuniform quantization scheme results in 0.5 to 2 dB improvement over the previous method.
本文对匹配追踪（MP）系数的选择和模量量化进行了精确的分析研究。我们证明，通过选择直至质量相关阈值的原子，并根据该阈值定义模量量化器，可以实现最优的率失真权衡。在此过程中，我们考虑了由于在MP原子计算循环中插入模量量化器而导致的量化误差再注入。循环内量化不仅提高了编码性能，还影响了均匀量化和非均匀量化的最优量化器设计。我们在视频编码的背景下衡量了我们工作的影响。对于均匀量化和非均匀量化，对原子选择和量化之间关系的精确理解在编码效率方面带来了显著提高。在高比特率下，所提出的非均匀量化方案比以前的方法提高了0.5至2 dB。
