Design And Implementation Of 3D Measurement System Based On MEMS Micro-Vibrating Mirror

The traditional 3D measurement system based on active structured light is to obtain the sine fringe between black and white through the defocusing technology of the projector.However,although the complete sine fringe pattern can be obtained by defocusing technology,the fringe pattern obtained is not accurate enough due to the focus length of the projector and other reasons.Therefore,in the measurement process,the phase measurement work needs to be completed by the mechanical moving optical elements,which leads to the problems of low measurement accuracy,heavy workload,poor measurement stability,etc.;at the same time,the huge and expensive projector is only used for projection strip leads to function waste,large volume,bulky and difficult to integrate.In order to solve these problems,the fringe projection technology based on MEMS(micro electrical mechanical system)is used to build a new three-dimensional measurement system in this paper.Firstly,the measurement principle of fringe projection system based on MEMS is studied,and the mathematical model is built.A data processing program is written with MATLAB for phase unwrapping.In this paper,a calibration method of MEMS based fringe projection system is proposed.The calibration chessboard corner is used as the "capture point" of MEMS fringe projection system,and the calibration of the system is completed.Compared with the phase-shift calibration method,it simplifies the calibration process and improves the calibration speed.Secondly,the hardware selection and module design of the 3D measurement system are completed,including the design of the control signal of the measurement system,the design of the laser driving circuit,the design of the galvanometer driving circuit and the design of the trigger circuit of the CCD camera.Finally,a 3D measurement system based on MEMS fringes is built and measured.The experimental results show that the fringe image based on MEMS is clear,the relative error of measurement is 1.86%,the average error is 0.631 mm,the standard deviation is 0.042 mm,and the measurement system is effective,feasible and stable.However,the stripe width is not uniform,showing the trend of narrow on both sides and wide in the middle.How toavoid this trend and improve the sine and accuracy of the stripe needs further study.