A New Adaptive Subband Thresholding Algorithm for Multistage Lattice VQ Image Coding

In this paper a new adaptive subband thresholding algorithm is introduced for finding the optimize threshold values of the subbands. The search technique is exhaustive, where the distortion level and bit allocation are used as the limiting factors. The algorithm is applied in multistage lattice VQ (MLVQ) to enhance the PSNR performance. The MLVQ image coding technique reduces the quantization error of the quantized vectors by "blowing out" the residual quantization errors with a LVQ scale factor. Experimental results for images using the adaptive subband thresholding technique and the MLVQ are shown to be superior to those of JPEG2000 for a set of test images