中文摘要：

基于传统小波变换过程复杂的特点和SPIHT编码算法过程重复运算、存储量大,并且侦查图像的目标像素小且目标数量大,相关性低,提出了一种基于差分脉冲编码调制和整数小波变换相结合的改进混合编码算法。首先以压缩效果为准则,以侦查图像为标准训练图像,以压缩比、峰值信噪比为参数来确定最优的小波基。然后以（9,7）整数提升小波对图像进行分解,对低频子带的重要系数先进行DPCM编码。最后对整个变换后的子带进行SPIHT编码。实验结果表明该算法在相同的比特率下得到的重构图像的PSNR值高于原算法,而且侦查图像的低频近似效果得到了改善。

英文摘要：

An improved omnibus coder arithmetic based on differential pulse code modulation （DPCM） and IWT is proposed, in view of the problems of complicated convolution process of wavelet transform, repeated calculations and a large number of memories of SPIHT algorithm, as well as the object pixels of spy image are very small and have big quantity, the relativity between the pixels in the frame is little. At first, the compression result is given as the standard, and the spy image as the standard training image, the compression ratio, PSNR and reserved energy percentage after compression are taken as parameters to look for the best wavelet filter. Secondly, the image is decomposed by using（9,7） tap integer lifting wavelet, the DPCM is used to code in the lowest frequency sub-band. Finally, the SPIHT are used to code all the sub-band after trans- formed. Experiments demonstrate that the PSNR value is higher than that of the original SPIHT at the same bit rate.