APMC: Adjacent Pixels Based Measurement Coding System for Compressively Sensed Images

Compressed sensing is now regarded as an effective method for dimension reduction during signal acquisition. One significant, yet under-addressed issue regarding the transmission of compressively sensed images is how to compress and code measurements, the output of a compressed sensing sensor. As the spatially adjacent correlation in the measurement domain is weak, conventional encoding algorithms cannot be applied directly for measurements. In this paper, we propose the adjacent pixels based measurement coding system (APMC) to generate compressed image bit-streams. Firstly, an adjacent pixels based measurement matrix (APMM) is applied to embed the pixel-domain boundary information of each block to the measurement domain. By adopting APMM, the pixel-domain information can be efficiently used for measurement-domain intra prediction. Moreover, to avoid the interference of pixels that are far apart and achieve a high prediction accuracy, we employ boundary measurements of neighboring blocks as references for prediction. Finally, we propose a rate control algorithm to process the residuals between measurements and predictions, to generate a coded bit sequence for transmitting. Experimental results demonstrated superiority in rate-distortion performance and bandwidth costs in transmitting as compared to previous schemes. Compared to the state-of-the-art, this work achieves a 24% decrease in bitrate and a 1.68 dB increase in Peak Signal-to-Noise Ratio (PSNR) on average.