Digital Image Compression Advanced Topics

Abstract

Segmentation is an image processing technique that can be used in many image applications. For instance, to perform optical character recognition, one usually needs to partition an image into small segments each of which contains a character. Segmentation based image coding is another application of image segmentation. By using this image compression method, one first segments an image into smaller pieces, and then encodes these pieces. The principle behind this method is that there is a strong correlation among the neighbor pixels, and by reducing this correlation redundancy through image segmentation and encoding each segment individually, an image can be compressed efficiently. Segmentation based image coding can lead to a very high compression ratio, for example, 100:1. In this section, three segmentation based image compression algorithms will be described. They are region growing, split-and-merge,and tree-structured segmentation algorithms.