基于整数小波变换的图像编码研究与仿真

Research and Simulation of Image Coding Based on Integer Wavelet Transform

对原始图像分块后,通过整数平方量化阈值编码与上下文相关的零树编码的有机结合,提出一种基于整数小波变换和整数平方量化阈值的上下文相关零树编码算法ISCZ(Integer Square threshold and Context-based Zerotree)。ISCZ算法不仅缩短了各量化阈值间的距离,增加了编码过程中零树的数量,而且充分挖掘了零树符号间的相关性,克服了基于提升框架的(5,3)等整数小波变换能量集中性差的缺点。实验结果说明,ISCZ算法对静态图像的压缩效果优于目前已有的小波压缩算法。

After image tiling, by combining integer square quantization threshold coding algorithm and context-based zerotree coding together, it is presented in this paper an algorithm called ISCZ, which is a novel context-based zerotree coding algorithm based on Integer wavelet transform (IWT) and integer square quantization threshold. ISCZ algorithm not only shortens the distances among quantization thresholds and improves the quantity of zerotree, but also exploits the correlation among zerotree symbols. So the problem of the worse energy compaction of (5,3)-IWT based on lifting scheme is resolved. Experiments results demonstrate that ISCZ performs better compression than the existing wavelet image compression algorithms.