The 3D scanning system for the machine vision based positioning of workpieces on the CNC machine tools

Abstract

In the paper some algorithms applied for the calibration of the 3D scanning system and image analysis in the experimental system for positioning the workpieces on the CNC machines are discussed. The idea of the scanning is based on the application of photogrammetric algorithms using the fringe patterns approach. An experimental system consisting of three cameras and three structural light projectors has been built in order to acquire the images representing the scanned object with projected light patterns. These images are then analyzed in order to obtain the depth information for each point representing the workpiece or the background. Nevertheless, a good accuracy requires a proper calibration of the system considering the distortions introduced by the optics of the cameras and projectors. After the calibration, the acquisition of image series and their analysis, the 3D model of the object, represented as a point cloud, is obtained as the result, which should be filtered and can be fitted into the known model. The results obtained in the conducted experiments have also been compared to the effects of the application of an available commercial system with similar cameras.