Retrieval Of 3D Model Based On Medial Axis Skeleton

With the wide application and rapid distribution of 3D models, 3D retrieval is becoming more and more necessary. Although text-based search engines are widely used today for multimedia data, such as 3D models, however, they usually lack in meaningful description for 3D models. Development of the technology for effective content-based search and retrieval of 3D models has become an important issue. It is thus necessary to have such a system that is based on the features intrinsic to the 3D models, most important of which is the 3D shape. Compared to text-based search system, the content-based search and retrieval of 3D models has more advantage for its objectivity, content-based retrieval, and fast retrieval.Through studying other techniques, two new 3D retrieval algorithms are put forward in this paper. These two algorithms all belong to topology-based retrieval. Before extracting feature form original 3D model, we need to do some pro-processing. There are two pro-processing: the principle cell analysis and the anisotropic transform.In retrieval of 3D model based on skeletal binary tree algorithm, we use a hierarchy-based algorithm. In the first instance, we improved the integer medial axis algorithm. The integer medial axis skeleton and the geometric information of 3D model were got. Secondly, a coarse-to-fine strategy was presented to calculate similarity between different 3D models. This algorithm can achieve better retrieving efficiency than other algorithms.In retrieval of 3D model based on block algorithm, the medial axis skeleton was segmented into a set of blocks by spatial region after the medial axis skeleton was got. Calculating the similarity of the blacks of 3D models got thesimilarity between different models. This algorithm can achieve better retrieving efficiency than other algorithms.The 3DMS(3D Model System) is a PC-based 3D retrieval system, which realizes the two methods provided in this thesis. The system's search mode is to finds similar 3D models through example model, which is simple and easy to use. The experiment result proves these two retrieval algorithms have a good retrieval result and fast retrieval speed.In the end, some key issues of 3D model retrieval for future research are also discussed at the end of this thesis.