Research On Key Technology Of Three-Demension Reconstruction In Commercial Reverse System

The combination of Reverse engineering with Rapid Prototyping brings a new pattern for product design & manufacturing, 3-D measuring. The 3-D laser scanning and measurement system has been developed and commercialized in the Center of Rapid Prototyping of HUST (Huazhong University of Science and Technology). Deep studies on reconstruction of 3D data and key techniques of 3D vision measurement for rapid inspection of products and reverse engineering are carried out in this dissertation.The quality of laser stripe images has direct effect on the accuracy of system. A new way to process laser stripe images is presented. In order to make further processing, the images need to be preprocessed so as to make images more clear with distinctive laser stripe boundary. Then the best-threshold image segmentation algorithm is put forward, and the dynamical images segmentation is carried into execution. In the mean time,the binary images can be obtained. Furthermore, single-pixel wide laser stripe lines are extracted by adopting a new thinning algorithm based on curve fitting. To obtain high accuracy of reconstruction of 3D data, the key thing is how to match the laser stripes more precisely and efficiently. As the existing of "blind view", the datum of reconstruction may be fragmentary. In tackling the problem, a new matching algorithm for laser stripe is present, which is based on laser plane-epipolar constraint. The factors that affect the accuracy of 3D reconstruction of 3D laser scanning and measurement system are analyzed, and methods of improving the accuracy are presented .It is proved in the experiment that they are feasible and effective.In order to get the 3D information of objects in time and then modify the shape of objects, A three dimensions measurement subsystem based on 3D laser scan and measurement system is designed. Lastly, least square fit method of sphere, parts like ladder blocks and arbitrary column is studied, and some other special dimensions calculation methods are researched.