A COMPARISON OF THE Z-LATTICES, E(8)-LATTICES, AND LEECH-LATTICES FORQUANTIZATION 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 measu re of the mean square error per dimension generated by quantization of a uniform source. Subband image coefficients, however, are best model ed by a generalized Gaussian distribution, leading to distortion chara cteristics that are quite different from those encountered for uniform , Laplacian, or Gaussian sources. We have calculated the distortion as sociated with Z, E(8), and Leech lattice quantization for coding of ge neralized Gaussian sources and show that for low bit rates, the Z latt ice offers both the best performance and the lowest implementational c omplexity.