Smoothness-constrained quantization for wavelet image compression

Uniform quantization of wavelet coefficients introduces perceptually distur bing artifacts by decreasing visual smoothness. In this paper, local Holder regularity is used to quantify these changes in visual smoothness. A modif ied uniform quantization scheme that constrains local regularity decreases is proposed. The quantizer modification is applicable to any uniform quanti zation scheme and requires no additional side information to be transmitted to the decoder, unlike standard deadzone quantizers. The reconstructed ima ges show a noticeable perceptual improvement as well as an increased PSNR r elative to uniform quantization.