为了快速获得更好的图像复原质量,提出了一种基于关系矩阵的快速嵌入零树小波(EZW)图像编码算法。该算法的基本工作步骤为:(1)对原始图像进行小波分解;(2)对最低频小波子带进行DPCM编码;(3)对所有高频子带系数构造零树结构;(4)首先确定初始阈值,并构造小波系数的关系矩阵,然后结合关系矩阵对高频子带系数进行逐次逼近量化编码。实验结果表明,该算法具有较好的图像复原质量和较快的编码速度,整体性能明显优于EZW方案(特别是低比特率下)。

In this paper,a new fast embedded zerotree wavelet(EZW) image coder based on relation matrix is presented.Firstly,the discrete wavelet transform is performed on the origin image.Secondly,the wavelet coefficients of the lowest frequency subband are encoded by using DPCM.Thirdly,the zerotrees are defined for the wavelet coefficients of the high frequency subbands.Finally,the initial threshold is identified and relation matrix is constructed,and the wavelet coefficients of the high frequency subbands are encoded progressively by using relation matrix.The experiment results show that the new still image compression scheme provides higher perceptual quality and less encoding time than EZW,especially at low bit rates.