An improved SPIHT image algorithm for space TDICCD camera

In order to solve the problem of slow processing speed of set partitioning in hierarchical trees (SPIHT) due to its dynamic processing order that depends on the remote sensing image contents, 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 4×4 blocks and simultaneously all the bits are encoded in a bit-plane of a 4×4 block. In order to realize the parallel processing mechanism, the three passes of the traditional SPIHT algorithm are reorganized. The reorganized three passes are encoded in a parallel and pipelined manner. The experimental results show that the proposed compression algorithm can work stably and reliably and has good compressive property. Compared with the traditional methods, the performance of average peak signal-to-noise ratio (PSNR) for our method corresponds to that of the conventional approaches. However, it is superior to others for the throughput. The improved SPIHT algorithm can process 120 million samples per second at an operating clock frequency of 100 MHz, greatly improves the image algorithm speed and is very suitable for the application of image for space CCD camera.