The Key Technology Research On Line Structured Light 3D Scanning System Based On Robot

In the changing trend of intelligent manufacturing,3d object data has been widely used in industrial measurement,reverse engineering,virtual reality,artificial intelligence and many other fields.However,traditional 3d data collection methods cannot meet the requirements of high precision,high efficiency and high flexibility in modern 3d measurement.Aiming at the problems of low efficiency,low stability of handheld scanning,low flexibility of stationary orbit scanning and limited measurement range,this paper proposes a line structured light 3d scanning system based on robot and researches its key technologies.The system inherits the advantages of high precision,non-contact and strong real-time of linear structured light measurement,and enhances the measurement flexibility and expands the measurement range.The content and innovation of this paper are as follows:(1)The 3d scanning model of line structured light based on robot is established.In the case that the robot terminal pose cannot be acquired in real time,the measuring coordinates of the line structured light measurement system at each position can be unified into the robot base coordinate system to complete the splicing of each three-dimensional cross-section point cloud of line structured light.According to the scanning principle and field conditions,the scanning system experiment platform is built,which combines the industrial robot and linear structured light measurement system,and the main hardware in the test platform is selected.(2)Camera model,linear structured light measurement model and robot hand-eye relationship calibration are realized in the system model.Among them,the second calibration of camera model parameters by zhang's calibration method can eliminate the influence of poor image quality on the calibration and improve the accuracy of camera calibration results.Matrix is proposed based on a single should sex fast calibrationmethod for measuring the line structured light,operate auxiliary device for calibration plate and light plane coplanar structure,with specific calibration board with pixel plane instead of the abstract in the plane of the light plane and the pixel,calibration plate does not need to repeatedly adjust position can complete light plane to single pixel plane should matrix calculation,calibration process simple and efficient,quick line structure light measurement model is established.Using Tsai's two-step calibration method to calibrate the hand-eye relationship,the spatial transformation from camera coordinate system to robot coordinate system was realized(3)According to the characteristics of light stripe image taken in practice,the image processing flow of light stripe center extraction is designed,and an improved gray-scale centroid method based on image skeleton is applied to realize the sub-pixel extraction of light stripe center.After comparative analysis,adaptive threshold method is used to realize binarization of image to retain effective information of light stripe.Four direction templates were used to approximate the normal direction of the light stripe skeleton,and the light stripe sub-pixel center in this direction was extracted by gray scale barycenter method.(4)Based on QT,OpenCV,OpenGL and other open source tool libraries,PC software of the test system was designed and developed with C++ language,and several measurement models were scanned to verify the feasibility of the system.