多光谱遥感图像CCSDS动态码率控制近无损压缩

Abstract

On the basis of CCSDS-123.0-B-1lossless compression algorithm of multi-spectral image recommended by the Consultative Committee for Space Data Systems(CCSDS),a rate control method of forward adaptive quantifying step size was proposed to achieve the nearly lossless compression with a fixed rate.The prediction method of CCSDS was introduced and the ranges of the upper bound and lower bound of Golomb-Rice coding were analyzed.By analyzing the relationship between prediction error and the compression rate,their approximate linear mapping curves were established.According to the mean value of prediction error,the quantization step size was adaptively estimated and the Golomb-Rice coding length was preliminarily controlled.In addition,taking the multi-spectral image rate control strategy under spaceborne conditions into account,the compression code rate was precisely controlled by fine tuning the quantization step size according to the feedback of compressionrate.At last,the processes of CCSDS nearly lossless compression rate control method was presented.The experiment results show that distribution area of k(Golomb coding variables)is stable.At the compression rate of 4∶1,the Peak Signal to Noise Ratio(PSNR)from the proposed method is 60.42 dB averagely,which is increased by 5.51 dB and 2.89 dB as compared with those from JPEG2000 and differential JPEG-LS methods respectively. The rate control method is accurate,easy to be implemented in hardware and suitable for aerospace engineering.