BUILDING SKELETON MODELS VIA 3-D MEDIAL SURFACE AXIS THINNING ALGORITHMS

In this paper, we present an efficient three-dimensional (3-D) paralle l thinning algorithm for extracting both the medial surfaces and the m edial axes of a 3-D object (given as a 3-D binary image). A new Euler table is derived to ensure the invariance of the Euler characteristic of the object, during thinning. An octree data structure of 3 x 3 x 3 lattice points is built to examine the local connectivity. The sets of ''simple'' points found by different researchers are compared with th e constructed set. Different definitions of ''surface'' points includi ng ours are given. By preserving the topological and the geometrical c onditions, our algorithm produces desirable skeletons and performs bet ter than others in terms of noise sensitivity and speed. Pre- and post processors can be used to remove additional noise spurs. Its use in de fect analysis of objects produced by casting and forging is discussed. (C) 1994 Academic Press, Inc.