Research On Error Modeling And Correction Of Multi-optical Channel 3D Measurement System

In recent years,with the development of sensing technology and intelligence,the demand for three dimensions(3D)digitalization has gradually increased.3D measurement of fringe projection technology based on phase calculation can obtain the morphological data of the object,and has the advantages of high accuracy and fast data processing,so it has been widely studied and applied.With the increasing demand for measurement speed,multi-optical channel 3D measurement technology come into being.This technology use multiple optical channels simultaneously,and multiple groups of fringe patterns can be obtained in one measurement,which improves the measurement efficiency and provides ideas for rapid measurement research.In the multi-optical channel 3D measurement,the measurement accuracy is restricted due to the coupling between the influences of multiple optical channels and the errors existing in the system optics.Although there are many researches on various errors,a simple and effective system error model and correction method are lacking.Therefore,the thesis establishes a system error model for multi-optical channel 3D measurement system errors,starting from the error type of image collection,and proposes a systematic error correction method.First,according to the structure of the multi-optical channel 3D measurement system,various error sources in the system are analyzed,and system errors such as crosstalk,chromatic aberration,distortion,and nonlinear errors are found.Various errors are measured by different methods,and the effects of various errors on the 3D measurement process and results are analyzed.Secondly,starting from the error type of image collected by the system,the system error is divided into the light intensity error between the image pixel brightness and the actual brightness and the positional deviation of the spatial distribution of the image pixels.An error model based on the light intensity error relation is established,including the effects of crosstalk between channels and non-linear errors on light intensity measurement results.An error model based on the position deviation relation is established,including the influence of channel color difference and distortion error on pixel position measurement results;Based on the above model,a system error correction method is proposed,and the distortion,chromatic aberration,crosstalk and non-linear errors existing in the system are corrected at the same time.Finally,the color fringe projection system is built and the system error is corrected by the proposed method,and the validity of the system error model and correction method is verified.The experimental results show that through the established error model and correction method,the 3D measurement error is reduced from 0.678 mm to 0.031 mm,which improves the accuracy of 3D measurement of multiple optical channels.