Dual-view 3D Measurement System Based On Phase Calculation

In optical three-dimensional(3D)measurement technology,phase-aided optical 3D measurement has the advantages of simple implementation,high accuracy,high resolution,rapid measurement,non-contact,etc.,and has always been a hot research subjects at home and abroad.It has received great attention and been widely applied in industrial design,biomedicine,on-line monitoring,machine vision and various fields.Due to the problems of shade and shadow,traditional single view 3D measurement system will exist the phenomenon of data missing obviously.To overcome the shortcomings,this paper has developed a dual-view 3D measurement system based on phase calculation.First,the measurement scheme and system structure have been proposed based on the principle of dual-view detection.According to the principle of fringe projection 3D measurement,two pieces of point cloud data are obtained by calculating absolute phase.System calibration is the key of ensuring the precision of 3D measurement system.The paper analyzes and compares the principle of the polynomial calibration method and the inverse camera calibration method,and corrects the eccentricity error of the calibration plate in the calibration process.The accuracy of center location of circles can be improved by 50% after correction.Second,the hardware platform of the dual-view 3D measurement has been built.Software program is designed to achieve the image acquisition,phase calculation,system calibration,three-dimensional display and other functions.Third,the developed system is calibrated.Compared with the two calibration results,it can be seen that the polynomial method has high accuracy,but the measurement range depends on the position of the calibration plate.The reverse camera method is simpler and the field of view and depth of field is larger,but its accuracy is not as good as the former.Finally,three-dimensional objects are measured.Transforming two 3D point cloud data in the same coordinate system obtains a complete and high accuracy 3D point cloud without shade and shadow.Therefore,the dual-view 3D measurement system not only can avoid the shade and shadow problem effectively,but also can increase the measurement field of view,and conducive to the overall shape of the measured object.