一种适于空间CCD图像压缩的SPIHT改进算法

针对传统遥感图像压缩多级树集合分裂排序(SP IHT)算法由于采用取决于图像内容的动态处理顺序而导致处理速 度缓慢这一问题,提出一种适于空间时间延时积分(TDI)CCD相机图像压缩的SPIHT改进算法 。首先,将小波变换后的图像分解成4×4块,同时对一个4×4块的 一个比特平面所有比特进行编码。为了实现并行处理机制,SPIHT改进算法重组传统SPIHT算 法的3个通道,然后采用并行和流水线作业的方式编码3个重组通道。实验结果表明,本文提 出的压缩算法可以稳定正常的 工作,具有良好压缩性能,平均信噪比(PSNR)性能与传统 方法相当,而数据吞吐率远高于传统方法。在正常100MHz时,数据 吞吐 率达到120Mpixle,大大提高压缩算法的处理速度。SPIHT改进算法 非常适合空间CCD相机图像压缩应用。

An improved SPIHT image algorithm for space TDICCD camera

In order to solve the problem of slow processing speed of set partitio ning in hierarchical trees (SPIHT) due to its dynamic processing order that depends on the remote sensing image con tents,an improved SPIHT image algorithm for space time delay integral CCD (TDICCD) camera is proposed in this paper.Firstly,a wavelet-transformed image is decomposed into 4×4blocks and simultaneously all the bits are encoded in a bit-plane of a 4×4block.In order to realize the parallel processing mechanism,the three passes of the traditional SPIHT algorithm are re organized.The reorganized three passes are encoded in a parallel and pipelined manner.The experimental results s how that the proposed compression algorithm can work stably and reliably and has good compressive prop erty.Compared with the traditional methods,the performance of average peak signal-to-noise ratio (PSN R) for our method corresponds to that of the conventional approaches. However,it is superior to others for the throughput.The improved SPIHT algori thm can process 120million samples per second at an operating clock frequency of 100MHz,greatly improves the image algorithm speed and is very suitable for the application of i mage for space CCD camera.