Research And Application Of Line Structured Light 3D Measurement System Of Binocular Vision Based On Point Cloud Fusion

With the rapid development of processing industry and manufacturing industry,along with the continuous advancement of modern detection technologies,the 3D measurement technology of workpieces composed of the irregular surface,has gradually become a research focus in the field of industrial measurement.The 3D measurement technology of line structured light based on laser triangulation has the characteristics of high precision,easy expansion,and strong robustness.It has become the most widely used and most promising technology for non-contact 3D measurement.When the traditional single-view 3D measurement system of line structured light deals with a relatively complex workpiece,there is a partial occlusion of the surface,resulting in incomplete measurement and data loss.To solve this problem,a 3D structured light system with binocular is designed in this dissertation.The line structured light is projected perpendicular to the surface of the workpiece under test.The positional relationship between the two industrial cameras and the line structure light is relatively fixed.Cameras and the line structured light are drived by the displacement platform to scan along the workpiece to obtain dual-view point cloud.After registration and fusion,a more complete 3D point cloud data is obtained for measurement.Some researches in the key technologies of this system have been done.1.Two kinds of 3D measurement of line structured light models based on the principle of laser triangulation are analyzed and deduced in this dissertation.According to the perspective projection model,hardware selection and software architecture design of the system are completed.2.According to the characteristics of the 3D structured measurement of line structured light system with binocular,a new type of calibration board is used to complete the integrated calibration of binocular cameras,line structured light plane and the displacement platform to obtain system parameters.3.In order to optimize the robustness of the traditional light stripe center extraction algorithm,a new light stripe center extraction algorithm based on Steger extracting method is used,which combined with the local threshold and Blob analysis.The light stripe center extraction algorithm can extract the center accurately even under the complicated situation.4.Aiming at improving the poor real-time performance of large-scale point cloud ICP registration,a method to compensate for the initial position deviation of point cloud is proposed.The accelerating experiment shows that the method can reduce the time by 90% compared with the common registration method.The height measurement experiment and the practical 3D measurement application of complex workpieces verify the effectiveness and practicability of the proposed algorithm.The measurement accuracy of the system can reach 0.05 mm.The overall reliability and the real-time performance of this system can meet the requirements of industrial online 3D measurement.