Swapping of reflections of adjacent subcodevectors for vector quantization

Vector quantization (VQ) has been widely used for compressing images. VQ of images requires significant memory and computational resources. Many methods have emerged to reduce either of these resources. A class of methods aimed at reducing the memory utilizes reflection of codevectors. This paper analyzes a scheme based on swapping of reflections of adjacent subcodevectors for jointly reducing memory and computational overheads. This scheme extracts the intra-vector redundancies to provide optimal quality. Studies are carried out on the convergence, utilization of the orientations, and performance of the scheme. Results are presented in comparison to a traditional scheme based on reflections of codevectors.