Image coding using a dynamic multi-layer address-vector quantization technique

A new vector quantization scheme for encoding monochrome and RGB color images is presented. The proposed technique is called dynamic multilayer address vector quantization (DMLAVQ) and is based on using vector quantization in a multilayer fashion. A three-layer coding system, where the codebook in the first layer is a standard vector quantization (VQ) codebook, and the codebooks in the other two layers are address codebooks with code vectors consisting of the addresses of the previous layer´s codebook, is simulated. In the first layer, a standard VQ is performed on each block of the image. In the second layer, the resulting VQ addresses of the neighboring blocks are merged together to form a new vector which is said to be address vector quantized if this address combination vector can be found in an address codebook. This process of merging four nodes (neighboring addresses) is repeated recursively in a bottom-up hierarchical manner in the subsequent higher layers using the corresponding address codebook in each layer. The proposed technique is based on a tree-structured merging of the nodes of a quadtree in a bottom-up manner to form a larger block, provided a merging criterion is satisfied