Research On Sounding Rocket Image Compression Algorithm

Sounding rocket based micro-gravity platform has not been developed in china. In order tohold superiority in space science, it is really in dire need to develop sounding rokcetmicrogravity experiment platform. Image is the fitest expression of micro-gravity experiment, sothe image’s real compression and transmission is vital for the success of microgravity experiment.Based on deep investigation and research on progress of sounding rocket based micro-gravityexperiment, this paper proposes an image system which fits sounding rocket well. Through theresearch on wavelet analysis theory and principle of wavelet image compression, this paperproposes a low bit rate lossy image compression algorithm and a lossless image compressionalgortism that both fit sounding rocket image system.The main work of this dissertation is summarized as follows.Firstly, this dissertation proposes a design scheme for sounding rockt digital image system.This system supplies the real-time adjustment to the image’s sampling resolution, frame rate andcompression ratio based on the scientific requirements of microgravity experiments. In ourdesign scheme, sounding rocket digital image system includes two systems: on board imageprocessing unit and ground receiving and decoding unit. On board image processing unit usingcorresponding modules to realize image acquiring, coding, storing, and transmission; groundreceiving and decoding unit uses corresponding modules to realize image receiving, decodingand displaying.Secondly, this paper designs low bit rate lossy image compression algorithm for soundingrocket, it has the advantages of low memory requirement low complexity, high efficiency andfitting for hardware implementation. The proposed algorithm adopts some technigues toeliminate lists of original SPIHT algorithm and enhance the algorithm’s scanning efficiency.Compared with original SPIHT algorithm, the proposed algorithm has super performance inPSNR and coding speed.Thirdly, this papar proposes a sounding rocket fitted lossless image compression algorithm.The algorithm deals wavelet coefficients differently according to their subband property. The lowfrequency subband fristly uses DPCM coding method to reduce the wavelet coefficients’ datadynamic range, then uses a modifed bit plane coding method to output the bit stream. The highfrequency subband is divied into three parts according to their band component, then codes themwith their thresholds repectively. In high frequency sub-part coding algorithm, by using type Aset’s judge, the algorithm optimizes the outputted bit stream, enhances the compression ratio. Also, through eliminating the lists and using advanced scaning methods, the algorithm reducesthe memory requirement, and becomes more efficient.