Block Truncation Coding

Like JPEG and JPEG2000 digital image compression techniques, Block Truncation Coding (BTC) is also an effective method for compressing image data. In traditional BTC, an input image of size PxQ is divided into blocks of size MxN, each of which can be processed independently. Each block uses only two colors, a and b, and their positions are determined by a binary bitmap. BTC achieves its compression goal by using such a small amount of data (originally MxNx8 bits; compressed to MxN+2x8 bits) to represent an image block.