图像编码方向自适应提升小波变换  

Direction-Adaptive Lifting Wavelet Transform for Image Coding

作　　者：王相海[1,2] 夏春宇[1] 宋传鸣[1] 

机构地区：[1]辽宁师范大学计算机与信息技术学院,大连116081 [2]湘潭大学智能计算与信息处理教育部重点实验室,湘潭411105

出　　处：《模式识别与人工智能》2015年第7期577-585,共9页Pattern Recognition and Artificial Intelligence

基　　金：国家自然科学基金项目(No.61402214;41271422);高等学校博士学科点专项科研基金项目(No.20132136110002);辽宁省博士科研启动基金项目(No.20121076);辽宁省教育厅科学研究一般项目(No.L2013405;L2013406;L2011192);智能计算与信息处理教育部重点实验室(湘潭大学)开放课题项目(No.2011ICIP06)资助

摘　　要：提出一种基于分块的图像编码方向自适应提升小波变换(DA-LWT),在每级变换中采用固定的方向块大小,仅保留一、二级变换所产生的方向信息,更高级别的方向由其前两级预测获得,从而减少边信息的开销.根据图像块的最小预测残差能量自适应选择滤波器的滤波方向,有效消除图像相邻像素间的冗余,降低高频系数能量.采用基于分数像素插值方案,提高方向分辨率.实验表明,DA-LWT的变换系数具有更好的"零树"特性,可取得比传统提升小波变换更好的编码效率和视觉效果.A direction-adaptive lifting wavelet transform （DA-LWT） based on block of image is proposed in this＇paper. The fixed size of directional block is used for each level of transform. Directional information is retained by the first and second level transform. The direction of higher level transform is obtained by the prediction of the first two levels, and the cost of side information is reduced. According to the minimum prediction residual energy, the filtering direction of filter is selected adaptively to eliminate the redundancy between neighboring pixels effectively and reduce the energy of high-frequency coefficients. Adopting the interpolation based on fractional pixel, and the direction resolution is improved. Experimental results show that the transform coefficients of image obtained by DA-LWT have a better ＂ zero-tree＂ feature. DA-LWT can obtain better coding efficiency and visual effects compared with traditional lifting wavelet transform.

关 键 词：方向自适应滤波 提升小波变换 图像编码 方向预测 

分 类 号：TP391.41[自动化与计算机技术—计算机应用技术]