A content-addressable memory architecture for image coding using vector quantization

An architecture suitable for real-time image coding using adaptive vector quantization (VQ) is presented. This architecture is based on the concept of content-addressable memory (CAM), where the data is accessed simultaneously and in parallel on the basis of its content. VQ essentially involves, for each input vector, a search operation to obtain the best match codeword. A speedup results if a CAM-based implementation is used. This speedup, coupled with the gains in execution time for the basic distortion operation, implies that even codebook generation is possible in real time (<32 ms). In using the CAM, the conventional mean square error measure is replaced by the absolute difference measure. This measure results in little degradation and in fact limits large errors. The regular and iterable architecture is particularly well suited for VLSI implementation