摘要
提出一种自适应方向提升小波变换算法。该算法将压缩的图像分成许多大小相等的子块,对每个子块,根据图像的统计特性(瞬时方差系数),自适应地选择提升方向和提升小波的类型。对方向信息较少的块,直接采用普通的水平和垂直提升。对方向信息较多的块,采用方向提升小波。实验结果表明:同DA-DWT算法相比,该算法能够显著降低方向小波变换的时间,同时在低码率下,PSNR有所提高。
A novel direction-adaptive wavelet lifting image compression algorithm is proposed. The image is partitioned into many nonoverlapping blocks using the algorithm. For each block the lifting wavelet is adaptively selected based on the image statistics （the instantaneous coeffi- cient of variation）. The normally horizontal and vertical lifting wavelet is used to transform blocks with little direction information, thus it reduces the computational complexity and the number of bits needed to code the direction information. The other blocks use directional lifting transform for increasing the prediction accuracy. Experimental results show that the proposed algorithm can dramatically reduce the computational time compared with the DA-DWT method, and the PSNR on standard test images is a little bit better than DA-DWT at very low bit rate.
出处
《数据采集与处理》
CSCD
北大核心
2009年第5期600-604,共5页
Journal of Data Acquisition and Processing
基金
教育部留学归国人员启动基金(20050466)资助项目
重庆市自然科学基金(CSTC
2009BB2358)资助项目
关键词
图像压缩
自适应方向提升
瞬时方差系数
image compression
direction-adaptive lifting
instantaneous coefficient of variation
