Abstract: In order to improve the result of image compression，this paper analyzes the basic concept of lift wavelet transform and the processing procedure，and advances an approach of lift wavelet image compression algorithm based on fractal coding and zerotree.Based on original method of lift wavelet image compression，a matching result is directly used to the wavelet subtrees with only few former lower resolution sub sets because of the poor self-similarities within higher resolution subsets when the matching forecast result of the images is processed.This means that the higher resolution subsets are not used to implement the fractal coding match but uses a improved method of lift wavelet coding.The hybrid image compression algorithm and the process based on wavelet transforming using both fractal coding and zerotree coding is improved.The experiment show，that the encoding time of this algorithm is remarkably speed up.At the same time，the essence and the improving direction of wavelet combine with fractal coding and zerotree coding is discussed in the paper.

Key words: wavelet image coding, fractal coding, hybrid coding, lift wavelet transfer, zerotree

摘要： 为改善图像压缩的效果，在讨论小波提升算法的基本原理与实现流程的基础上，提出了一种改进的基于提升小波变换的零树分形混合图像编码算法。在基本小波提升算法的基础上，考虑到在对小波子树匹配预测时，经提升小波变换后的高分辨率子带自相似性不强的特点，不对高分辨率子块进行分形匹配，而直接用前几个较低分辨子带的匹配结果作为小波子树的匹配结果，改进了基于提升小波系数零树结构的分形预测图像编码方法及过程。实验结果表明，这种改进显著加快了编码速度，编码所花费时间仅为常规方法的十分之一。最后，阐明了小波与分形进行图像压缩相结合的本质和仍需改进的方向。

关键词: 小波图像编码, 分形图像编码, 混合编码, 提升小波转换, 零树