Modified Runlength Coding for Improved JPEG Performance

A number of image compression systems have been developed to save storage space and transmission bandwidth. The field of image compression has witnessed a lot of research on improving JPEG or evolving a codec with better performance. In the JPEG standard, run length encoding is used to code the string of zeros resulting from crude quantization of AC coefficients. In this paper we propose modified runlength JPEG (MR-JPEG), which uses separate coding of three symbols (RUNLENGTH, SIZE, AMPLITUDE) to code the information. To compare the results with the earlier scheme, we use two parameters-maximum difference (MD) for perceptual quality measurement and size (in KB's) for compression. Our results show that for large size images (512times512 and above), proposed scheme demonstrates higher compression with better quality.