Research On Three-Dimensional Measurement Based On Multi-line Structured Light

Three-dimensional measurement has always been a research hotspot in computer vision,and it is also the research foundation in the field of stereo vision.Compared with other 3D measurement technologies,the measurement technology based on multi-line structured light has been widely used in the measurement field because of its flexible and simple operation and strong anti-interference ability.Therefore,it is of great significance to conduct in-depth research on it.This paper mainly studies the measurement principle and calibration method of the multi-line structured light 3D measurement system,as well as the three-dimensional data acquisition.First,the system components and technical principles are analyzed.The small hole imaging model,triangulation principle and binocular stereo vision model used in the system are briefly introduced.Then the calibration method of the multi-line structured light 3D measurement system is explained,and the parameters of each component in the system are obtained.Use the standard checkerboard calibration board to obtain the internal parameter matrix and external parameter matrix of each camera,the basic matrix and eigen matrix of stereo vision,etc.In order to solve the problems that multiple light planes are difficult to distinguish during the calibration process and the image needs to be preprocessed,an innovative method based on ROI line selection is proposed,which can quickly and conveniently extract the center point of the laser stripe of each light plane.Using the homography matrix,the two-dimensional pixel coordinates of the center point of the laser stripe are converted into three-dimensional camera coordinates,and the multi-line structured light plane equation is calibrated.In the process of stereo vision matching for binocular multi-line structured light,the surface shape of many tested objects is complicated,which leads to the problem of not being able to find accurate matching points.A matching point screening method based on back reprojection is proposed,which improves the utilization rate of the center point of the light bar in the system measurement process and improves the system measurement efficiency.In addition,by adding a matching window to analyze the error between the projection point and the center point of the light strip during the matching process,it is proposed to dynamically adjust the size of the matching window to improve the utilization of the laser stripe center point and the unique matching rate.Finally,the actual measurement system is built,and the actual measurement experiment is carried out using the innovative and improved measurement method proposed,and the validity and reliability of the method are verified through the experiment.Experimental data shows that the measurement efficiency of the multi-line structured light 3D measurement system can be significantly improved,the measurement time is shortened,and the quality of the 3D model is improved.