A New Context-model for the Pseudo-distance Technique in Lossless Compression of Color-mapped Images

In this work, we propose a method that utilizes a new context model along with a pseudo-distance technique in compression of color-mapped images. Graphic Interchange Format (GIF) and Portable Network Graphics (PNG) are two of the well-known and frequently used techniques for the compression of color-mapped images. There are several techniques that achieve better compression results than GIF and PNG; however, most of these techniques need two passes on the image data, while others do not run in linear time. The pseudo-distance technique runs in linear time and requires only one pass. We show that using the proposed context model along with the pseudo-distance technique yields better results than both PNG and GIF.