Analogcast: Full Linear Coding and Pseudo Analog Transmission for Satellite Remote-Sensing Images

Abstract

In this paper, we propose a novel image coding and transmission scheme called AnalogCast, which is a pseudo analog coding system for transmitting satellite remote-sensing images to large number of receivers. AnalogCast follows the idea originally developed for SoftCast [1-3] but with two special techniques, scale factor estimate based on L-shaped chunk division and scale factor fix curve-fitting model, so that there is no need to transmit side information as is required for SoftCast [1-3]. This improvement can get better mobility, less bandwidth and computational budget than SoftCast [1-3]. For robustness, AnalogCast adopts a mode of GOP (Group of Pictures) interweave structure to smooth image quality and improve perceptual quality when packet loss happens. Experimental results show that the proposed method can work well in low SNR condition in -7dB to 4dB where SoftCast system and JPEG2000 system fall into “cliff effect”. And in high SNR condition, our proposed method works even better than SoftCast system at SNR 1.5~3dB and a gain of 1~10dB over JPEG2000 with forward error correction. For robustness, the AnalogCast works better than SoftCast at SNR 8dB when the burst packet loss rate is higher than 35%. And the scheme gets better perceptual quality under packet loss.