Compression of Digital Images by Block Truncation Coding: A Survey

Block truncation coding is a lossy moment preserving quantization method for compressing digital gray-level images. Its advantages are simplicity, fault tolerance, the relatively high compression efficiency and good image quality of the decoded image. Several improvements of the basic method have been recently proposed in the literature. In this survey we will study the basic algorithm and its improvements by dividing it into three separate tasks: performing quantization, coding the quantization data, and coding the bit plane. Each phase of the algorithm will be analyzed separately. On the basis of the analysis, a combined BTC algorithm will be proposed, and comparisons to the standard JPEG algorithm will be made.