IMAGE COMPRESSION USING VQ-BTC

Vector quantization (VQ) and block truncation coding (BTC) are successful image compression techniques, However, 31 a reproduced image using VQ or BTC suffers from edge degradation. In this paper, a new technique that combines the advantages of both VQ and BTC to combat this degradation is presented and will be referred to as VQ-BTC. In VQ-BTC, a low-detail block is encoded using VQ. For a high-detail block, a modification of BTC is used to determine the locations of the relatively lighter and relatively darker pixels inside the block and VQ is then used to encode each, VQ-BTC provides improved edge reproduction and much lower bit rates than those obtained by BTC.