Research On The Simplification And Surface Reconstruction Of Dental Scattered Point Cloud

CAD/CAM technology applied in denture cosmetology will substitute for the traditional manual prosthetics, but there are little denture CAD/CAM systems used in China at present. Meanwhile, The construction of the three-dimensional denture model is always the core of the denture computer-aided design/computer-aided manufacture (CAD/CAM) systems, however, the precision and the efficiency of the three-dimensional model closely connected with the data reduction and surface reconstruction of the large amounts of original point data. The existing point cloud reduction and surface reconstruction technology cannot completely meet the special requirements of denture treatment. In this context, the thesis research about the Point cloud streamline and Surface reconstruction, which are the underlying systems of the denture CAD/CAM systems.The thesis acquired the original point clouds from the scanning equipment in our college laboratory and the teeth stamping provided by Stomatological Department of the fist affiliated college. According to the Small volume and the Big changes curvature of the denture, the thesis also Puts forward the denture point cloud streamline algorithm which is based on the Grid method and the String differential method. First, topological reconstruct a large number of original discrete point cloud data through the method of three-dimensional grid. Then assess and retain the lager curvature points also with their curvatures and binormal vectors. So use the fewest number of points to realize the most effective expression. Experiments show that, streamline algorithm method is simple and efficient, suitable for the messy disorder point cloud data measured from the reverse engineering. It can streamline Lots of dense data directly and effectively, and it can contain more detail information of the area which has larger curvature and more detailed features.Based on the streamline algorithm, This paper put forward the surface reconstruction algorithm which is based on the largest regional growth curvature method. First choose the initial triangle and a block through the Initial triangular K neighborhood, in this area to grow triangulations. And then combining with the Point cloud'curvature acquired by the Streamline algorithm, search the effective triangle the point cloud point points. And get a new regional block from the point's K neighborhood to growth triangulate, until all the simplified point clouds are triangle. Experiments show that, the surface reconstruction algorithm can not only triangle the point cloud effectively, but also priority triangle the more point cloud and the larger curvature area,and so make the larger curvature area triangle more thoroughly and the details more prominent.