3-D Measurement System Study Based On Coded Structured Light

Phase measuring profilometry becomes one of the most widely used structured light 3D measurement technology and it has huge potential in many fields,such as industrial detection,reverse engineering,precision measurement,cultural relics protection etc.In the past ten years,the phase measuring profilometry toward the development of fast and high precision direction.However,many commercial measuring equipment at present use physical grating or laser as projection device,which is high cost,and limited the technology being apply in small companies.Based on the application of detection of PCB electronic circuit board in industrial inspection,this paper research the key techniques of structured lighted system based on digital fringe projection,including phase calculation,system parameters calibration and dedicate to develop low cost and high accurate structured light 3D measuring system,which is adoptable to small and medium-sized companies.The main contents of this paper are as follows: 1.The whole phase calculation including phase calculation and phase unwrapping.In order to improve the burr phenomenon in gray + phaseshift of the phase unwrapping process,this paper proposed a simple improved method.Experimental results show that this method can effectively eliminate burr error.Then with comparison of different phase unwrapping algorithm,we choose gray+phaseshift as the unwrapping algorithm.2.Research on projector calibration algorithm based on coded structured light.The relationship between the image points of the projector and the image points of the camera is established by encoding the structured light,so that the projector has the function of "camera",so that the camera calibration method can be used to calibrate the parameters.According to the orthogonal gray code due to the projector and camera resolution not only lead to inconsistent image point correspondence problem,propose a method based on centroid calculation point correspondence.3.Development and application of structured light 3D measurement system.Based on the above theory and technology,this paper developed a 3D measurement system,the distance precision can reach 0.02 mm within the plane error 0.2mm,then use the prototype of PCB electronic circuit board of the three-dimensional reconstruction and measurement,the practical application shows that the system can be on the PCB electronic circuit board copper the height is measured,is conducive to the production and testing of industrial automation.