Robust source coding for images over very noisy channels

Robust source coding provides both compression and noise mitigation without channel coding. In this paper, two methods of robust source coding are presented. The first is DPCM incorporating a nonlinear filter; the second is Predictive Trellis-Coded Quantization (PTCQ), whose prediction filter is also nonlinear. Findings show that the incorporation of the nonlinear filter provides the ability to conceal the effects of noise and minimize the propagation of error. A comparison is made between the performance of the two methods in a noisy environment. It is demonstrated that the PTCQ scheme provides a method of least distortion at low BER. However, at higher BER the DPCM scheme outperforms PTCQ. Robust source coding of images employing PTCQ or DPCM with the nonlinear prediction filter exhibits low sensitivity to bit errors and yields, visually, a better reconstructed image after transmission over very noisy channels. 1