Research On Data Segmentation Technology In Reverse Engineering

Reverse engineering technology as a new type of product development form plays a key role in shortening product development period, absorbing advanced technology and experience, increasing product competitiveness. The products generally constructed by quadratic surface and free-form surfaces through extension, transition and spilt joint. It is difficult to describe product surface with a sole surface mathematical model. In order to improve the quality of reconstruction surface, shorten product development period, the point cloud segmentation is needed and the segmentation results directly affect the surface fitting and the CAD model reconstruction quality.Data segmentation is based on the point cloud date of products surface. But during the data acquiring, the working environment and self-defect of measuring equipment will cause the obtained dates existing many noise points. The Triangular mesh model which is established on these dates usually have many errors such as self-grid errors,normal vector errors,overlap errors,vertex errors and isolated grid errors. All these errors will impact later date segmentation .In order to solve this problem, a data preprocessing technical route is given. First, the error triangles are identified and deleted it, forming a single hole errors. Then, repairing the hole errors. Finally, the smooth method base on triangular mesh's curvature and the main direction is used to remove the noise dates. Through experiment results show that the technical route can effectively reduced or eliminated the impact of the error dates.The present point cloud segmentation has summarized. The concept through withdrawing transition surface to segment the point cloud is proposed. Aiming at the edge-based method and surface-based method existing problems, proposed two stage segmentation method. Through the successful segmentation of the experiment block which contains basic surface and transition surface, the experimental results prove the validity of this method. Two stage segmentation method is applied in automobile steering knuckle and motorcycle covering parts and basically realizes the separation of the basic surface and transition surface. The segmentation results show that the method can meet the requirement in engineering application. The designed cover parts and knuckle fork shell have been put into market and have better economical benefits.