Source and Channel Coding of Images for Noisy Channels
Phillip Gregory Sherwood · 2000
Wireless multimedia devices and services are beginning to emerge and will continue to increase in popularity as capabilities improve. The demand to improve quality and increase the capacity of such systems within limited bandwidth resources motivates the interest in efficient and error-resilient image coding methods. An important problem is how to efficiently encode images for transmission over limited-bandwidth channels while maintaining good decoded im-age quality and resilience to channel impairments. This thesis investigates the problem of robust image transmission over memoryless, fading, and packet erasure channels. First, a system consisting of a high-performance embedded wavelet coder followed by a concatenated channel code is proposed for transmission over memoryless channels. The system maintains the progressive nature of the source coder, has reasonable complexity, and exceeds the performance of previously known systems. Error resilience and progressivity are further explored through the problem of channel code parameter (block length and channel code rate) optimization for progressive transmission. A general performance measure for evaluating progressive image coding quality is proposed and a dynamic programming optimization algorithm is presented. Results are included for erasure channels and bit error channels. In