A COMPARISON OF THE Z-LATTICES, E(8)-LATTICES, AND LEECH-LATTICES FOR QUANTIZATION OF LOW-SHAPE-PARAMETER GENERALIZED GAUSSIAN SOURCES

In lattice vector quantization, the distortion associated with a given lattice is often expressed in terms of the G number, which is a measure of the mean square error per dimension generated by quantization of a uniform source. Subband image coefficients, however, are best modeled by a generalized Gaussian distribution, leading to distortion characteristics that are quite different from those encountered for uniform, Laplacian, or Gaussian sources. We have calculated the distortion associated with Z, E(8), and Leech lattice quantization for coding of generalized Gaussian sources and show that for low bit rates, the Z lattice offers both the best performance and the lowest implementational complexity.