Topology preservation and tricky patterns in gray-tone images

Abstract

A gray-tone image including perceptually meaningful elongated regions can be represented by a set of line patterns, the skeleton, consisting of pixels having different gray-values and mostly placed along the central positions of the regions themselves. We discuss a skeletonization algorithm, computed over the Distance Transform of the image and employing topology preserving operations. Differently from the binary case, where the use of the connectivity test is generally sufficient to create a one-pixel-thick skeleton, we consider also a suitable labeling of the pixel neighborhood. In this way, we are able to deal with some of the tricky patterns in the gray-tone image that can be regarded as irreducible. © Springer-Verlag Berlin Heidelberg 2003.