A Study Of 3D Model Reconstruction From Cloud-of-Point Coordinates

With the recent development of 3D data collection technologies and hardware facilities (e.g. laser and structured light), the higher requirements of authenticity, real time and interaction of computer graphic visualization, the demands of CAD, CAM and other quick molding technologies, the technology of triangle mesh generation and simplification have become one of the hotspots in the field of 3D reconstruction. The basic thought of triangle mesh generation and simplification is to process disperse data points obtained by 3D measurement or the output results from molding software to generate data in a standard and common format, wipe off the redundant information while at the same time by keeping the accuracy of the model to guarantee the real-time graphic visualization, the efficient of data storage and quickness of data transmissionThis thesis sums up some classical algorithms of surface reconstruction with vast disperse data and several simplification algorithms of triangle mesh. Based on these algorithms and the features of the data obtained by our 3D measurement instrument, a new surface construction and simplification algorithm is presented in this thesis. Using these algorithms, the programs are efficient and the obtained graphics of triangle mesh are of good quality, which meet our requirements quite well. The detailed results of the research are listed below:1. Presents an algorithm of triangle mesh generation of disperse data points based on dynamic circles. This algorithm is efficient, and the obtained cured surface is of good quality. It processes these data that gathered from the optical measurement system or other 3D measuring apparatus directly without thepreprocessing of wiping off noise points. User can define the resolution of the exported triangle mesh through setting a few parameters. It still can process other information of the points of cloud except for the x, y, z coordinates, such as color information (RGB). Besides, several feasible ideas of texture mapping are presented in this paper.2. Presents an algorithm of 3D model represented in simplified triangle mesh. This algorithm adopts the 2nd derivative of the curvature of the curved surface as the condition of simplification and the edge contraction as the basic simplification manner. The concept of quadric error is introduced in the generation of a new vertex.3. The results of the numerical experiments are visualized using OpenGL. The real-time processing results of three dimensions can be viewed on the screen. And the model can be zoomed , panned and rotated.4. It is easily to export three-dimensional geometry with a mapped texture into .VRML format. So we can directly export these data into Internet and use the data in other software, and extend the range of application.