Adaptive interleaved vector quantization for image transmission

A novel image-coding scheme, adaptive interleaved vector quantization (AIVQ), has been devised for still-image transmission. Interleaved vector quantization begins by decomposing the image into several interleaved subimages. These subimages are then coded separately using vector quantization. Since strong correlation exists between them, adaptation can be implemented by coding only one or two subimages in the low-detail areas. Since the remaining packets contain only noncontiguous pixels, their values can be reconstructed well with linear interpolation, AIVQ is a variable-bit-rate coding scheme which allocates bits according to the local detail level in the various regions of the image. In other words, this algorithm assigns more bits to the high-detail than to the low-detail areas of the image. Therefore, AIVQ provides an efficient coding scheme which delivers constant image quality with variable transmission rate, as needed in a packet-switched network. Experimental results demonstrate that excellent reconstructed images are obtained at bit rates in the range of 0.3-0.5 b/pixel