说明：  SPIHT编码算法是EZW的改进算法，它能够生成一个嵌入位流，使接收的位流在任意点中断时，都可解压和重构图像，因而具有很好的渐进传输特性。
(SPIHT coding algorithm is the improved EZW algorithm, it can generate an embedded bit-stream, so that bit-stream received at any point of failure, can extract and re-image, which has good properties of progressive transmission.)