基于小波变换的分形图像编码

在分析小波变换后系数分布特点的基础上，提出了一种新的基于小波变换的分形图像编码算法．根据小波变换后能量集中于低频的特性，在传统的Jaquin分形编码方案的基础上，引入局部Harr小波变换，以低频子图代替原图进行值块、域块间的匹配计算以加快搜索过程，从而提高编码速度．结果表明，该算法在峰值信噪比下降很少的情况下。编码速度提高了100多倍，证明了其高效性．

Fractal Coding Based on Wavelet for Image Compression

The auto-coding method of fractal image based on the theory of iterated function system, has the advantage of high compression ratio and fast decoding with resolution-independent. But the computational complexity of the encoding process prevents the progress of fractal image coding. By analyzing the distribution of the coefficients after wavelet transformation, the paper proposed a new fractal coding based on wavelet transformation, which differs from the traditional method of fractal coding in the wavelet domain. According to the characters of energy concentration after wavelet transformation, the algorithm introduces part wavelet transformation on the basis of Jacquin's fractal coding method and replaces the original image with its low-frequency image to compute the matching process between domain blocks and range blocks, which speeds up the searching process and quickens the process of encoding. From the results of the experiments, the algorithm enhances the coding speed by more than 100 times, compared with the traditional Jacquin method, while the peak signal ratio loses less.