A lattice vector quantizer for generalized Gaussian sources

A fixed-rate lattice vector quantizer for generalized Gaussian (GG) sources is presented. By using the contour of constant probability of a generalized Gaussian source to bound the integer lattice, this vector quantizer in the limit of high dimension achieves optimal boundary gains for GG sources. Low-complexity techniques for rate control, optimal codevector search and enumeration are developed. This coder achieves 8.60 dB for a generalized Gaussian source with shape parameter of 0.5 at 1 bit/sample (compared with a rate distortion bound of 9.23 dB) and 32.62 dB for the 512×512 “Lena” image at 0.25 bpp without the use of entropy coding. By using two small lookup tables, the nearest codeword search operation can be performed multiply-free and the overall quantization process costs one multiply and a few adds per sample