Research On Model Reconstruction And Repairing Based On Industrial CT Image Data

Due to the feature of non-destructive and non-contacting of detecting the workpiece, Industrial Computerized Tomography(ICT) is widespread used in the Reverse Engineering(RE). Mesh model reconstructed on the slice Images of ICT equipment not only desplays the inner structure, composition and defects intuitively and accurately, but also used for solid modeling and innovative design. It is a efficient way to design a new product or to absorb good experience from forerunner. However, because of the limits of measurements, algorithm, the mesh model also has some defects, such as holes, topology error etc. In order to solve the above problems, this paper studies reconstruction and the hole-repairing methods, describes the process of reverse engineering design, also gives some sample. The main works are listed as follows:① Review the methods of 3D reconstruction, describe the model reconstruction based on industrial CT slice data, focus on the isosurface extraction method: MC(Marching Cubes) algorithm, analysis on defects of the models.② Present a novel hole-repairing algorithm. Firstly, identify holes and do pre-processing on the holes. and then the local geometric information of the hole boundary is accurately calculated through a novel definition of normal estimation method of incomplete 1-neighbor triangles, especially calculate the hole edges’ projection angle on the tangent plane of the boundary vertex, which can obtain the more accurate features of the vertex with large curvature parts. Finally, improved advancing front mesh method is performed, in which two mechanism to produce the triangle mesh is defined: triangle growth order controled by the edge’projection angle on the tangent plane and the vertex’flat degree, and one more, the adjustment of the new inserted vertex according to the directional curvatures of the adjacnt edge. As a direct hole-repairing method and considering the local curvature, the proposed approach has smooth transition with the surrounding meshes. Examples show that the new algorithm can obtain the high quality mesh model which can be benefit for post- processing.③ The algorithm mentioned above have been integrated into a reconstruction system(named 3D-RCS) designed by our research team. The mesh model has been achived and used to bulid the solid model by the reverse design software UG.④ Studies the route of reverse design based on industrial CT technology, and through a spceific application demonstrates the process of the reverse design, provides a solution to absorb the advanced technology.