基于标准差的图像分块自适应压缩方法  

Image block adaptive compression method based on standard deviation

作　　者：汪澜[1] 李艳阁 张海涛[2] 

机构地区：[1]辽宁工程技术大学矿业技术学院,辽宁葫芦岛125105 [2]辽宁工程技术大学软件学院,辽宁葫芦岛125105

出　　处：《辽宁工程技术大学学报（自然科学版）》2017年第11期1212-1217,共6页Journal of Liaoning Technical University (Natural Science)

基　　金：国家自然科学基金(61172144)

摘　　要：针对传统小波变换缺乏必要的方向性和Contourlet变换给图像造成空间冗余性的缺点,提出一种基于标准差的图像分块自适应压缩方法.该方法首先将图像分成大小为N?N且互相分离的若干子块;然后计算各子块的标准差,通过各子块标准差确定阈值,根据子块标准差与阈值大小自适应选取小波变换或Contourlet变换;最后在编解码段,通过引入快速排序算法对SPIHT编码LIP列表中的像素值进行递归排序,进一步提升了编码效率.实验结果表明,本文方法融合了小波变换和Contourlet变换的各自优点,在保证重构图像拥有较多纹理信息的同时降低了Contourlet变换产生的空间冗余性,并且使重构图像的峰值信噪比在一定程度上有所提高.Because traditional wavelet transform lacks the necessary direction and Contourlet transform causes the spatial redundancy to the image, an adaptive compression method for image segmentation was proposed based on standard deviation. Firstly, the image is divided into several sub blocks,the size of the sub blocks is N ？N and they are separated from each other. Then the standard deviation of each sub block is calculated. Threshold is determined by standard deviation of each sub block. According to the sub block standard deviation and threshold size, the wavelet transform or Contourlet transform is selected. Finally in the coding and decoding section, this study recursively sort the pixel values in the LIP list in the SPIHT code by introducing a fast sorting algorithm, which further improves the coding efficiency. Experimental results show that the advantages and disadvantages of wavelet transform and Contourlet transform are combined in this paper. In ensuring that the reconstructed image has more texture information, it reduces the spatial redundancy of the Contourlet transform. And the peak signal to noise ratio of the reconstructed image is improved in a certain extent.

关 键 词：小波变换 CONTOURLET变换 标准差 图像分块 SPIHT算法 

分 类 号：TP391[自动化与计算机技术—计算机应用技术]