Study On Three-dimensional Graphical Location Technology Based On Visual Inspection

More and more visual inspection stations are put in use in the automobilebody_in_white measurement. There are many visual sensors in every visualinspection station. In an automobile body_in_white inspection station, how to locatevisual sensor precisely is one key problem. In this dissertation a graphic positioningmethod is proposed to adjust all the many dimensional parameters synthetically, ahollow tetrahedron is used for a positioning target to replace all the edges of astandard automobile body. So it's possible to trace a virtual standard automobile bodywithout a real body. This technology is called virtual positioning technology.The features of virtual location technology are: (1) the position of the visualsensor in the world coordinate frame is unique determined;(2) no necessary ofprocedure of global calibration;(3) one virtual edge is used to substitute for edge ofreal body, the virtual edge can has relationship to drawing directly;(4) graphicaldisplay, which makes the compositive adjustment easier to digital display, and easy toobserve.The dissertation concentrates on the study of visual sensor and virtual locationtechnology. The main and creative works in the dissertation includes the followingaspects:1.The calibration of the two-dimensional visual sensor is studied. A newcalibration method is proposed based on the calibration theory of measurement andthe characteristic of the instrument, and the primary calibrating experiments arecarried out.2.In order to calibrate the two-dimensional visual sensor, an instrument isdesigned to measure the plane of light;the design includes the mechanical design andthe circuit design.3.After calibration, the two-dimensional visual sensor can be used to simplymeasure the length of two-dimensional object;the experiments are carried to measurethe error.4.To realize the virtual location, a many dimensional worktable is designed;theequipment can realize the hollow tetrahedron to move in many directions5.The image processing algorithms needed in the system are studied;ahigh-speed and high-efficiency image processing method is advanced. In addition,many simple operate interfaces are designed in the dissertation.6.A method to measure the repeatability error of virtual positioning technology ispresented, the experiments are carried out and the result is obtained.7.The system is redesigned and realized based on all the study and experimentsof the dissertation, and the experiment worktable and tutorial are designed to train thestudents' skill of synthetically experiment.