This paper presents a new segmentation and coding algorithm for nonbinary images. The algorithm performs contour coding of regions of equally valued and connected pixels. It consists of two distinct phases: raster scanning and border following. In this sense it is similar to algorithms presented by Kruse. However, the algorithm of this paper is considerably improved since it correctly segments truly nonbinary images. The basic idea of the algorithm is to “coat” (color, label) the borders (the cracks) between the regions from both sides in two separate border-following procedures called island following and object following. Thus, all adjacencies between the objects are systematically explored and noted. Furthermore, the raster scanner, which exhaustively searches the image for new regions, can easily determine from existing/nonexisting coating which boundaries have been traced out and which have not. The algorithm can be considerably simplified for the binary image case.
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