Fast lattice-based gain-shape vector quantisation for image-sequence coding

A fast lattice-based gain/shape vector-quantisation method (FLGSVQ) is presented. The proposed technique combines the basic ideas of gain/shape vector quantisation (GSVQ) with lattice codes to offer an encoding process which is extremely fast compared with the conventional GSVQ. A simple single-/two-stage coding system based on lattice quantisation is tested for interframe predictive coding of image sequences. Simulation results are provided to compare the performance of the proposed method with the conventional LBG-designed vector quantisation. These results, along with subjective evaluations, clearly demonstrate that lattice quantisation can be competitive with vector quantisation in terms of signal-to-noise performance, only at a very small fraction (4%) of the vector-quantiser complexity.<>