Height ridges of oriented medialness
Stephen M. Pizer, Jacob David Furst · 1999
Shape analysis of objects is an important aspect of medical image processing. Information gained from shape analysis can be used for object segmentation, object-based registration and object visualization. One shape analysis tool is the core, defined to be a height ridge of a medial strength measure made on an image. In this dissertation I present 3D cores, defined here to be optimal scale-orientation height ridges of oriented medial strength measurements. This dissertation covers (1) a medial strength measurement, Blum-like medialness, that is robust, efficient, and insensitive to intrafigural interference, (2) a new definition for a ridge, the optimal parameter height ridge, and its properties, and (3) an algorithm, Marching Ridges, for extracting cores. The medial strength measurement uses Gaussian derivatives, so is insensitive to noise, and responds to object boundaries at points rather than on entire spheres, so is faster to calculate and less sensitive to boundaries of other image figures. The Marching Ridges algorithm uses the grid structure of the image domain to identify ridge points as zero-crossings of first derivatives and to track ridges through the image domain. I include results of this algorithm on medical images of cerebral vasculature, a skull, kidneys, and brain ventricles.