Image coding with uniform and piecewise-uniform vector quantizers

Novel lattice vector quantizer design procedures for nonuniform sources are developed that yield excellent performance while retaining the structure required for fast quantization. Analytical methods for truncating and scaling lattices to be used in vector quantization are given and their utility is demonstrated for i.i.d. Gaussian and Laplacian sources. An analytical technique for piecewise-linear multidimensional companding is derived, and the effectiveness of the multidimensional compandor designs is evaluated for i.i.d. Gaussian and Laplacian sources by performance comparisons with other vector quantizers. The uniform and piecewise-uniform lattice vector quantizers are then used to quantize the discrete cosine transform coefficients of images, and their objective and subjective performance and complexity are contrasted with other lattice vector quantizers and with LBG (Linde, Buzo, Gray) training-mode designs