COMPRESSION OF DIGITAL IMAGES BY BLOCK TRUNCATION CODING - A SURVEY

Block truncation coding (BTC) is a lossy moment preserving quantizatio n method for compressing digital gray-level images. Its advantages are simplicity, fault tolerance, the relatively high compression efficien cy and good image quality of the decoded image. Several improvements o f the basic method have been recently proposed in the literature. In t his survey we will study the basic algorithm and its improvements by d ividing it into three separate tasks; performing quantization, coding the quantization data and coding the bit plane. Each phase of the algo rithm will be analyzed separately. On the basis of the analysis, a com bined BTC algorithm will be proposed and the comparisons to the standa rd JPEG algorithm will be made.