The Technology Of Surface Reconstrction And Realization In Reverse Engineering

The Free-form Surface reconstruction is an important research content in reverse engineering. The precision and quality of the modeling play a vital role in producing high quality parts quickly. So it has important theoretical significance and practical value to study Free-form Surface Design technique which based on scanning point cloud.Scanning point cloud is the foundation of Free-form surface modeling. Obtaining point cloud data and the preprocessing point cloud data are analyzed in this paper. The key technologies of the preprocessing point cloud data, including multi-view data registration data filtering, data sampling, data mending, data block, are researched in this paper. Three point registrations and ICP (Iterative Closest Point Algorithm) algorithm are used to register for multi-view data. The angle-and-chord's algorithm is advanced which is based on chordal deviation algorithm for data sampling. The method is proved to be effective and right by some examples. Bezier and NURBS are chosen as the fundamental methods to achieve surface reconstruction after discussing the fundamental theory of surface reconstruction. The two methods are proved to be effective by some examples. The geometric continuity is the standard that the surface joining is smooth or not after further discussing the parametric continuity and geometric continuity. The methods of the two surface pieces and several surface pieces are joined by Coons surface and by Bezier surface are discussed. Besides, theoretical analysis, algorithm design and program composition are completed. The results of the different surface joining are analyzed and compared.A free surface modeling prototype system, which is based scanning point cloud, is completed by OOD technology, windows XP operating system and Visual C++6.0 as exploiting tools, combine OpenGL three-dimension graph standard. This system has basic function of point cloud's input and visualization, curve and surface fitting from the point cloud, surface joining. Besides, all the process of Free-form Surface Design is disposed and can be observed visually, and the feedback result of calculation and analysis can be obtained at any moment.