作　　者： ; ; ;

机构地区： 深圳信息职业技术学院

出　　处： 《计算机工程与应用》 2007年第12期36-39,共4页

摘　　要： 基于块离散余弦变换的图像压缩编码,在低比特率时其重构图像的块边界上会产生严重的方块效应。提出了一种空间域的自适应去块效应算法。首先把块效应建模成阶梯函数,然后根据判断准则把图像块分成平滑块,纹理块和边缘块。对平滑块,首次导出了块效应强度的表达式,然后根据块效应强度和平滑度进行自适应平滑滤波;对边缘块和纹理块,采用简单的Sigma滤波器对块边界周围的像素滤波。大量的仿真实验结果表明提出的算法有优越的去块效应性能。 A major drawback related to the block-based discrete transform （BDCT） for image compression is that the decoded images,especially at very low bit rates,exhibit highly noticeable discontinuities at the boundaries of blocks,namely blocking artifacts.In this paper,a novel adaptive de-blocking algorithm is proposed to reduce blocking artifacts.Blocking artifacts are modeled as step function in this paper,then the image blocks are divided into three categories.They are smooth blocks,texture blocks ,edge blocks.For smooth blocks ,the expression of amplitude of blocking artifacts is educed firstly in our algorithm,then the adaptive smooth filter according to amplitude of blocking artifacts and the smooth degree function is proposed to reduce blocking artifacts.For the texture blocks and edge blocks,the Sigma filter is used to smooth the block boundaries in the algorithm.The experiment results show that the proposed algorithm reduces the blocking artifacts effectively and preserves the original edges faithfully.

关 键 词： 块效应 块离散余弦变换 后处理 自适应平滑

领　　域： [自动化与计算机技术] [自动化与计算机技术]