针对分形图像压缩编码时间过长的缺点,提出一种改进算法,利用子块的相似特征,将基本分形图像压缩的全搜索过程,转化为相对差意义下的最近邻搜索,在搜索过程中只搜索与值域块相对差相近的码本块,减少了搜索范围。实验结果表明,该方法与基本分形图像压缩相比,在保证解码图像质量的同时,有效地加快了编码速度。
To reduce the long encoding time of fractal compression algorithm,this paper proposes an improved algorithm.It uses the similar characteristics of sub-block,and converts the basic fractal image coding's entire search into the nearest neighbor search of a relative difference defined in this paper,and to the only search of the domain blocks which have the same difference.This method can reduce the search space. Experimental results demonstrate that,compared with the basic fractal image coding,the proposed algorithm can speed up the encoding process with the gurantee of the image's quality.