A Tracking Approach for the Skeletonization of Tubular Parts of 3D Shapes

In this paper we propose a new simple and efficient method to characterize shapes by segmenting their elongated parts and characterizing them with their centerlines. We call it Tubular Section Tracking, because it consists of slicing the interested volume along different directions, tracking centroids of the extracted sections with approx- imately constant centroid position, area and eccentricity and refining the extracted lines with a post processing step removing bad branches and centering, joining and extending the relevant ones. We show that, even using just a few slicing directions (in some cases even just three perpendicular directions), the method is able to obtain good results, approximately pose independent and that the extracted lines can be more informative on the relevant feature of the objects than the classical skeletal lines extracted as subsets of the medial axis. Estimated lines can be used to segment shapes into meaningful parts and compute useful parameters (e.g. length, diameters)