基于小波系数零树结构的分形预测图象编码

提出了一种基于小波系数零树结构的分形预测图象编码方法，首先按照零树结构在同方向不同分辨率的各个子带图象上确定要预测的图象块（Ｒａｎｇｅ Ｂｌｏｃｋ），也就是将这些图象块串起来构成一棵与零树相类似的图象树（Ｒａｎｇｅ Ｔｒｅｅ）；然后，对每一图象块，在同方向低一级分辩率的子带图象上寻找与其最佳分形匹配的相似块（Ｄｏｍｉａｎ Ｂｌｏｃｋ），而这些相似块也按照零树结构上下延伸，以产生多棵相似树（Ｄｏｍａｉｎ Ｔｒｅｅ），其中与图象树最接近的相似树就是图象树的预测树，理论分析和实验结果表明，该方法在峰值信噪比稍微下降的情况下，能够获得较高的压缩比。

Fractal Predictive Image Coding Based on Zerotrees of Wavelet Coefficients

A new fractal predictive image coding scheme based on zerotrees of wavelet coefficients is presented. Wefirst pick out the range blocks to be predicted based on the zerotrees from subimages of the same orientation butdifferent resolutions. These range blocks will form a range tree, something like zerotrees. For each range block,we then look for its optimum fractally-matched domain block in the subimage of the same orientation but lowerresolution than that of the range block. Each domain block obtained this way can extend through differentresolutions along the same orientation to form a domain tree. Among all these domain trees, one closest to therange tree will be its predictive tree. Theoretical analysis and experimental results presented in the paper show thatour scheme can obtain higher compression rate at the little cost of signal-to-noise ratio.