International Journal of Engineering and Technology

Block truncation coding is one of the simplest compression techniques where the image is divided into blocks and then processed. The traditional method involves computation of a high mean and the low mean to replace the original pixel values. Here the first and the second moments are preserved and the bit rate is a constant value (2 bits per pixel). The major disadvantage is that there are heavy blocking artifacts when the block size increases. Many methods have been evolved in order to improve the compression ratio and also to reduce the bit rate. In this paper an improved block truncation coding algorithm along with an adaptive lossless compression scheme is proposed to improve on the compression ratio and Peak signal to noise ratio. The computational complexity is also further reduced and the blocking artifacts which are inherent in the traditional BTC are also minimized to a great extent.