Perceptual quantization for wavelet-based image coding
M.G. Ramos, Sheila S. Hemami · 2002
A psychovisually-based quantization strategy for wavelet coded images is proposed. The quantization strategy is based on the results of a psychovisual evaluation to quantify sensitivities to supra-threshold distortion caused by wavelet coefficient quantization in natural images. Quantizer step sizes to produce a minimum noticeable distortion are parameterized in terms of subband standard deviation and a quantization strategy is subsequently proposed. The resulting strategy is applied to both intraband and embedded wavelet coders and reveals a significant perceptual improvement when images exhibit supra-threshold distortion.