【摘要】 提出了一种考虑人眼视觉系统特点的四叉树分割编码算法。在分析视觉系统对比度特性的基础上，首先提出了一个基于视觉敏感度的四叉树分割标准。该标准性能优于常用的块方差。基于这一标准，我们把原始图象分割为３２×３２、１６×１６的均匀块和８×８的待分类块。对８×８块进一步应用一个基于对比度和多项式近似误差的二级分类器。最终，所有图象块被分为如下三类：具有不同大小的均匀块、８×８平滑块和８×８非平滑块。这三类图象块分别采用块均值、二维一阶多项式和ＤＣＴ编码进行近似。实验结果证实了所提出的算法性能大大优于ＪＰＥＧ国际标准。更多还原

【Abstract】 In this paper, a segmentation based hybrid image coding algorithm is proposed which takes the features of the human vision system (HVS) into account. First, a novel criterion for quadtree based segmentation using contrast masking is presented. This segmentation criterion performs better than the frequently used criterion, block variance. With this criterion, the original image is segmented into uniform blocks of 32×32, 16×16 and blocks of 8×8 to be classified. Then a two level classifier, based on contrast masking sensitivity and polynomial approximation error, is further applied to the blocks of 8×8 such that all blocks are classified into a few categories: uniform blocks of different sizes, smooth blocks of 8×8 and non smooth blocks of 8×8. At last, block mean, polynomial approximation and DCT coding are applied to the blocks accordingly. The experimental results demonstrate that the proposed algorithm performs much better than JPEG.更多还原