IMAGE COMPRESSION USING VQ-BTC

Vector quantization (VQ) and block truncation coding (BTC) are success ful image compression techniques, However, 31 a reproduced image using VQ or BTC suffers from edge degradation. In this paper, a new techniq ue that combines the advantages of both VQ and BTC to combat this degr adation is presented and will be referred to as VQ-BTC. In VQ-BTC, a l ow-detail block is encoded using VQ. For a high-detail block, a modifi cation of BTC is used to determine the locations of the relatively lig hter and relatively darker pixels inside the block and VQ is then used to encode each, VQ-BTC provides improved edge reproduction and much l ower bit rates than those obtained by BTC.