该文提出了一种Contourlet变换和小波变换相结合,使用新的空间方向树的类似SPIHT编码算法。该算法先对图像进行Contourlet变换,再对变换后的低频子带进行多级小波变换,然后根据变换后系数的结构特性,借鉴小波SPIHT编码思想,构造了一种新的空间方向树,实现了对变换后系数的类似SPIHT编码。仿真实验结果表明,该算法与小波变换,Contourlet变换和基于小波的Contourlet变换的SPIHT算法相比,重构图像保留了更多的纹理和细节信息,并且在低比特率下具有较高的峰值信噪比。
In this paper, a new Set Partitioning In Hierarchical Trees(SPIHT) coding algorithm is proposed, which is based on a Mixed Contourlet and Wavelet Transform(MCWT) and a new spatial orientation tree (MCWT-SPIHT). In the proposed image coding algorithm, Contourlet transform is employed for the first stage then followed by wavelet transform for the coarse scale. According to the structure properties of the MCWT coefficients, a new spatial orientation tree is developed to perform the SPIHT-like coding algorithm based on SPIHT coding idea of wavelet transform. Experimental results demonstrate that the proposed algorithm is competitive to wavelet transform, Contourlet transform and Wavelet Based Contourlet Transform(WBCT) with SPIHT in terms of Peak Signal to Noise Ratio (PSNR) at low bit rate, and it contains more contours and textures in the reconstructed images.