形状自适应的嵌入式小波图像编码算法

Shape-Adaptive Embedded Wavelet Image-Coding Algorithm

为实现任意形状区域编码,提出了一种形状自适应的嵌入式小波图像编码算法.该算法借鉴低存储器的零树编码(LMZC)方法引入系数重要性矩阵和子孙重要性矩阵以减少存储空间的使用,并引入最大幅值变量以避免对后代系数的重复扫描.编码过程中,当树结构的编码开销大于增益时,采用直接位平面编码.实验结果表明,该算法执行速度快、存储器需求低,在相同压缩比情况下,图像重构质量和峰值信噪比(PSNR)均优于LMZC与等级树集分割(SPIHT)算法.利用该算法对任意形状对象进行压缩编码可取得良好的压缩效果.

This paper proposes a shape-adaptive embedded wavelet image-coding algorithm to code arbitrarilyshaped region. The algorithm introduces the significance state matrixes of coefficient and offspring aggregate according to the LMZC （ Low Memory Zerotree Coding） algorithm to reduce the memory requirement, and applies the maximum amplitude variable to avoid the repeating scan of offspring coefficients. In the coding process, if the coding spending of tree structure is greater than the plus, the bit plane method is adopted to code the wavelet coefficients. Experimental results show that the proposed coding algorithm possesses high implementation speed with small working memory, and that, as compared with LMZC and SPIHT （Set Partitioning in Hierarchical Trees） algorithms at the same comp Signal to Noise Ratio）, th ges with compression ression ratio, it may result in better image reconstruction quality and larger PSNR （Peak us coming to the conclusion that the proposed algorithm can code arbitrarily-shaped imaefficiency.