Knowledge-based approach for 3D skeleton extraction

Abstract

A 3D skeleton is a one-voxel thick, graph-like structure, widely used in the area of a character animation. In this paper, we propose a novel method for the 3D skeleton extraction of the polyhedral models based on a priori knowledge of the learned skeleton. The method has several steps. First, the octree of the input model is calculated and used to compare with the octree of the 3D models stored in the octrees database. By comparing the octree similarities, if the searched results exactly match with the input octree, the corresponding skeleton will be retrieved from the skeletons database. Otherwise, the method finds the list of the close match (the octree similarity ratio which the value is greater than 0.8) in order to use to estimate the new skeleton. In the worst case, if the input octree does not match with any case in the octrees database, the method computes the new skeleton and stores it in the skeletons database. The method is fast and efficient because it is not necessary to extract the skeleton from every input model. Thus, the computational time of our method depends only on the time of the octree similarity calculation, and the time for searching the similar octree in the octrees database. Several examples show the results obtained with our approach. Copyright © 2009 ACM.