基于多级零树编码的小波系数网格编码量化

该文提出了对小波图像作多级零树编码后进行网格编码量化（TCQ）的新方法。首先利用子带间的相关性进行零树编码，然后利用卷积编码和信号空间扩展来增大量化信号间的欧氏距离，并用Viterbi算法寻找最优量化序列。仿真结果表明，该方法比零树编码后采用最优量化要提高0．3dB左右。该方法还具有编码计算复杂度适中，解码简单的优点。

Tcq of wavelet coefficients based on multi-stage zerotree coding

A new method which performs Trellis Coded Quantization(TCQ) of wavelet coefficients based on multi-stage zerotree coding is proposed. First, the zerotree coding utilizes correlation between the subbands, then convolutional coding and signal space expanding are used for increasing Euclidian distance between signals. Finally, Viterbi algorithm is used to find a optimized survived quantized sequence.Simulation states that this method has an advantages of 0.3dB or so over optimized scalar quantization after zerotree coding. The method also has such capability that it has only modest encoding complexity with simple decoding.