Research On The Measurement And Unified Calibration Method Of Multi-field Laser Contour System

With the development of the industrial automation technology,the combination of computer vision technology and practical application has become the key research direction of the industrial detection.The industrial environment is relatively complex,and it involves different requirements of measuring field.So the measurement technology is required to have higher adaptability.The 3D laser contour measurement technology plays an important role in industrial production due to the flexible measurement field,range and high accuracy.Laser plane calibration is the key point of laser contour measurement.At present,the method of laser plane calibration focuses on the calibration of a single field of view system,while the unified calibration method of different field of view laser contour measurement system is pending.Therefore,the unified calibration method is of great significance for the further application of laser contour measurement system in different measurement field.The realization of 3D laser contour measurement system mainly includes laser plane calibration and laser center extraction.The existing laser plane calibration method is only applicable to a single field measurement system.This thesis proposes an adaptive calibration method,through designing concentric plane targets with different radius and center distance,using the moving method to implement the calibration of different fields.Then analyzing the calibration error to improve the calibration accuracy.In order to realize the further accurate measurement of the scanned object,the center point segmentation fitting method is improved to segment the continuous line and curve features based on G0 and G1.Firstly,extracting the center point of laser by Hessian matrix,then combined with curvature and the least squares line fitting to get segment points.Then fitting the region by polynomial.The continuous segmented region of G1 is transitioned by the Hermite interpolation method to obtain the smooth point cloud.In order to verify the adaptability,accuracy and stability of method,this paper uses the same calibration system to calibrate the parameters of three laser contour measuring systems with different fields.According to the result of calibration,several experiments are carried out on two standard workpieces about height measurement.The RMSE is 0.006?0.07 mm,and the standard deviation is 0.0007?0.0082 mm.For the part of segment point extraction,the extraction error of segmented points under simulation data is small,and the actual data also has better segmentation results.