Positioning of scanned part inside of the laser triangulation system

Abstract

Laser triangulation method is not applicable in all possible areas, due to the presence of numerous disturbances. The method of predictive segmentation of laser line resistant to interference, which allows use in industrial quality control of the glossy elements, has been proposed. It requires precise synchronization with the CAD model of the scanned item. Very high accuracy of positioning is required to enable predictive segmentation of laser prole. -The worse positioning, the widest condential intervals, and worse algorithm's ability to reject specular re ections. The most universal way to synchronize the model of a part under laser scanning, with its virtual model, is to use an extra camera and some 3D matching software. This solution, however, is rather of poor accuracy -even if a high quality optics is used. Kalman ltering is used to reduce the deviation of results. To avoid problems in description of such complicated system, a coherent and homogeneous mathematical description has been proposed. It uses so-called Denavit-Hartenberg notation, widely used in robotics. Several tests has been carried out to verify the 3D matching algorithm for object-model synchronization during laser scanning. The results show clearly that the accuracy of matching can be improved by using Kalman ltering -even up to 10 times. Thanks to it, its accuracy increases to face the requirements of predictive segmentation algorithm.