基于局部方差的快速分形图像块编码算法

在分形图像块编码中，大部分时间花在序列块和较大的主池间寻找紧密的匹配上，对一幅较大的图像来说，由于主池按指数地增加，这种时间上的耗费便加剧了。本文提出了利用主块局部方差来减少搜索的空间，通过根据其局部方差排序收缩的主池，我们可以把所有可能的紧密匹配都限定在一个相对小范围的窗口来限制搜索空间，而在得到同样编码图像质量前提下同满搜索方法相比，编码的时间可以被缩短，其提高的速度可以达10倍左右。

A FAST FRACTAL IMAGE BLOCK CODING ALGORITHM BASED ON LOCAL VARIANCE

In fractal image block coding, most of the time is spent on finding a close match between a range block and a large pool of domain blocks. For a large image, this effect becomes aggravated as the domain pool increase exponentially. In the paper, we propose using the local variance of domain blocks to reduce the search space. By sorting the contracted domain pool according to their local variances, we can confine all the potential close matches to arelatively small sized window to limit the search space. The encoding time can hence be shortened with the decoded image quality as good as that using the full search method, and the speedup can be ten times.