Proposed two shift-coding based compression techniques

Image compression is gaining good deal of attention and development nowadays. There are many uses and benefits incorporated with this application. Compressing an image will reduce its size to some amount that will enhance its storage or transmission over a network. In this paper, we proposed and compared two (Shift Coding) based techniques that we developed to gain the best compression ratios while affecting the quality the less as possible. The first method (with leading short word) uses 4 bits to represent a byte if its value is less than 15 while the second one uses an indicator to give the byte either 4 bits or 7 bits. The second method (with lead bit) works better when most of the bytes are greater than 15. The average PSNR achieved was 33.45 and the average CR was 16.28.