CODEBOOK ORGANIZATION TO ENHANCE MAXIMUM A-POSTERIORI DETECTION OF PROGRESSIVE TRANSMISSION OF VECTOR QUANTIZED IMAGES OVER NOISY CHANNELS

We describe a new way to organize a full-search vector quantization co debook so that images encoded with it can be sent progressively and ha ve resilience to channel noise, The codebook organization guarantees t hat the most significant bits (MSB's) of the codeword index are most i mportant to the overall image quality and are highly correlated. Simul ations show that the effective channel error rates of the MSB's can be substantially lowered by implementing a maximum a posteriori (MAP) de tector similar to one suggested by Phamdo and Farvardin, The performan ce of the scheme is close to that of pseudo-gray coding at lower bit e rror rates and outperforms it at higher error rates, No extra bits are used for channel error correction.