An image coding scheme based on perceptually classified VQ for high compression ratios

In this paper we present a coding scheme for color images aiming at high compression ratios. It is based on perceptually classified vector quantization (VQ), where the different classes are chosen to achieve a better quality of the decoded image. Spatial correlation is reduced by a tree structured wavelet decomposition, then prediction of the insignificant coefficients is performed across subbands. Afterwards, the reduced set of data is organized in vectors in such a way that residual intra and inter band correlation are exploited. Finally, such vectors are coded by a classified VQ. Reconstructed images with good quality and a compression ratio higher that 100:1 have been produced by the proposed scheme, which has been shown to outperform the JPEG standard.