Research And Compensation Of Optical System Error Of Color Coded Structured Light For 3D Measurement

In recent years,with the development of information technology and industrial automation,trades and professions have more demands for 3D measurement technology,and the measurement requirements are also increasingly high.The traditional contact measurement or manual measurement can not meet the requirements of high efficiency and high precision.Compared with the traditional binocular vision measurement or monocular black-and-white coding measurement technology,color coded structured light measurement method has the characteristics of high efficiency and no coating,which has increasingly become a research hotspot in the field of 3D measurement.However,due to the introduction of color information by color coded measurement technology,the measurement results are easily affected by the optical chromatic aberration in the system,resulting in the reduction of measurement accuracy.Therefore,this paper analyzes the lateral chromatic aberration error of the optical system in the color coded structured light system and proposes the compensation method to improve the measurement accuracy of the system.Firstly,the working principle and calibration principle of structured light threedimensional measurement system are introduced,and the structured light threedimensional measurement experiment based on color Gray code is designed.Based on projection transformation,the system is calibrated.Secondly,in order to analyze the influence of optical system chromatic aberration on the measurement results,the projection points of different colors are projected onto the calibration plate in this paper.By comparing the position information of different color points at the same position of the image plane of the projector in the camera image plane,the lateral chromatic aberration distribution law of the camera and the projector lens is observed and analyzed.Thirdly,using the theory of geometrical optics,the transfer of chromatic aberration of optical system in the projector coordinate system is mathematically deduced,and the mathematical model of chromatic aberration of optical system is established according to the deduced results.Based on the model and the distribution of lateral chromatic aberration,a compensation scheme for lateral chromatic aberration of optical system is proposed.The feasibility of the compensation scheme is theoretically analyzed and experimentally verified by projecting RGB projection points to high-precision flat plates.Finally,the experimental platform of color coded structured light system is built.The system is calibrated by using high-precision electric translation stage and calibration plate.The measurement of standard plane and gypsum portrait is completed by using color Gray code coding patterns,and the measurement results are compensated.The experimental results show that the proposed optical system error compensation scheme can improve the measurement accuracy of color coded structured light system.