Contour-based shape representation for image compression and analysis

With the rapid growth of computing power, many concepts and tools of image analysis are becoming more and more popular in other data processing fields, such as image and video compression. Image segmentation, in particular, has a central role in the object-based video coding standard MPEG-4, as well as in various region-based coding schemes used for remote-sensing imagery. A region-based image description, however, is only useful if it has a limited representation cost, which calls for accurate and efficient tools for the description of region boundaries. A very promising approach relies on the extended boundary concept, first discussed in [6] and [7] and later used by Liow [5] to develop a contour tracing algorithm. In this work, we extend Liow's algorithm and introduce the corresponding reconstruction technique needed for coding purposes. In addition, we define an algebraic semi-group structure that allows us to formally prove the algorithm properties, to extend it to other boundary definitions, and to introduce a fast contour tracing algorithm which only requires a raster scan of the image.