基于灰度差的快速分形图像编码

Fast fractal image coding based on gray difference

分形图像编码根据图像自身的相似性,利用迭代函数系统理论,可以获得较高的压缩比,但是编码时间长却限制了分形图像编码方法的广泛应用。在迭代函数系统的理论理出上,介绍了一种基于灰度差排序的编码方法。该方法分别计算Range块和Domain块的灰度差,然后通过比较二者的灰度差,并且设定灰度差阈值,加速了Range块搜索最佳Domain块的过程,大大缩短了图像的编码时间。实验结果表明,在图像解码质量基本保持不变、压缩比得到提高的情况下,编码时间得到了明显的减少。

According to self-similarity of the image,fractal image coding can get very high compression ratio based on the iteration function system theory.However,the long coding time limits its application.An improved coding algorithm based on gray difference taxis with the same theory is presented.By comparing the gray difference of range block and domain block,the gray difference range could be fixed,which thereby speed up the process of searching for the best domain block by range block.The result of experiments shows that this method reduce the coding time a lot while maintaining good image coding quality and a high compression ratio.