【摘要】 基于Ｄａｖｉｓ提出的分形图象编码的小波理论，本文提出一种有效的小波域四叉树分形图象编码方案．在此方案中，利用小波系数的零树减少域块的个数，以降低表示分形编码局部信息所需要的比特代价；并对编码方案中采用的一组标量量化器、小波子树自量化器和判决树进行全面的熵约束最优化．实验结果表明：在低比特率下，编码方案的峰值信噪比性能比已报道的结果提高了约１ｄＢ．更多还原

【Abstract】 This paper presents an efficient quadtree based fractal image coding scheme in wavelet transform domain based on the wavelet based theory of fractal image compression introduced by Davis. In the scheme, zerotrees of wavelet coefficients are used to reduce the number of domain blocks, which leads to lower bit cost required to represent the location information of fractal coding, and overall entropy constrained optimization is performed for the decision trees as well as for the sets of scalar quantizers and self quantizers of wavelet subtrees. Experiment results show that at the low bit rates, the proposed scheme gives about 1 dB improvement in PSNR over the reported results.更多还原