扩展方向树的遥感图像小波包压缩算法

针对遥感图像纹理丰富、空间相关性弱,普通压缩算法容易造成高频信息丢失的特点,本文利用小波包优良的高频分析能力,提出一种结合SPIHT的小波包编码算法.该算法采用类似SPIHT算法的零树结构,通过重新定义方向树,即扩展方向树,改变小波包各节点之间的对应关系,解决小波包分解时产生的"父冲突"问题.同时,对扩展方向树的合理性进行了实验验证,并结合SPIHT算法实现了整个编解码.实验结果表明,对于富含纹理的遥感图像,在1bpp的压缩率下,该算法峰值信噪比(PSNR)超出SPIHT算法0.5-1dB,且视觉效果更好.

Wavelet Packet Compression Algorithm for Remote Sensing Images with Extended Spatial Orientation Tree

For remote sensing images,ordinary image compression algorithm always loses crucial features,such as edges and texture,during the coding procedure.A new compression scheme is proposed based on wavelet packet which has good performance on image detail processing.The problems arising from the application of zero tree-based algorithm to wavelet packet transform are analyzed.A generation version of parent-children relationship,named Extend Spatial Orientation Tree (SOT),to solve the parental conflict is defined.Combined with SPIHT,Extended SOT Wavelet Packet Codec (ESOT-WPC) is realized.Experimental results show that,under the same compression rate,the new codec method outperforms SPIHT in terms of Peak Signal-to-noise Ratio (PSNR) and vision.