Research On Calibration Technology Of 3D Measurement System Based On Line-Structured Light

With the development of urban rail transit, the speed of railway transportation and people increasingly pursuing travel comfort in our country, it puts forward higher requirements on the stability, safety, low noise characteristics of the transport vehicles. So it is very important to detect and trim the wheel tread surface. Accurate measurement is a prerequisite for wheel tread surface detection and trimming, and the measurement technology based on line structured light has the advantages of good real-time performance, easy operation, wide measurement range and high accuracy. Therefore, this technology can be used as the key technology of the wheel tread surface measuring machine in this paper.Calibration technology is one of the key technologies in 3D reconstruction based on structured light. In order to obtain the 3D information of any object in space, calibrating the parameters of the measurement system is needed first. In this paper, taking the major scientific and technological innovation project in Hubei Province as support, the camera,sensor calibration, and feature point extraction and other key technologies are studied,and the corresponding experiments are conducted to verify their effectiveness.The main work of this paper is as follows: The modeling work of the underfloor wheel tread surface measurement system is completed; In this paper, the existing camera mathematical model and calibration method are analysed and studied. On the basis of this,by considering two distortion effects(radial distortion and tangential distortion) and using a nonlinear optimization to obtain all the model parameters of the camera, the calibration method of 2D target is improved;Several commonly used methods of line structured light sensor parameter calibration are analysed in this paper. Finally the calibration method based on 2D target is designed to achieve the calibration of the light plane, and based on the MATLAB and OpenCV, the calibration algorithm is implementated completely; The experimental platform is designed and set up at the end of the paper. According to the foregoing calibration method, the corresponding experiment processes are designed and the calibration experiments are completed, and experimental data and error analysis are carried out. Experimental data show that the improved camera calibration method has ahigher calibration accuracy and the calibration process is fast, simple and easy to operate,and has application value.