Pattern Recognition in Computer Integrated Manufacturing

In this paper a new approach to an automatic controlled system of manufactured parts is suggested. Inputs of the system are: an unordered cloud of 3D points of the part and its CAD model in IGES and STL formats. The 3D cloud is obtained from a high resolution 3D range sensor. After registration between the cloud of points and the STL CAD model, the cloud is segmented by computing the minimal distance and compared to some local geometric properties between the 3D points and the NURBS surfaces. Controlled results are displayed in two ways: visually, using a colour map to display the level of discrepancy between the measured points and the CAD model, and a hardcopy report of the evaluation results of the tolerance specifications. The computing times are 2 seconds for a model STL made up of 15000 triangles put in correspondence with an image made up of 20000 points and about 10 seconds for the same image put in register with the same object represented with its model NURBS.