条纹偏折术检测凸球面元件曲率半径方法研究  

Deflectometry-Based Investigation of Radius of Curvature of Convex Spherical Elements Testing Method

作　　者：刘鑫 李大海[1] 张新伟 葛忍好 严子良 Liu Xin;Li Dahai;Zhang Xinwei;Ge Renhao;Yan Ziliang(College of Electronics and Information Engineering,Sichuan University,Chengdu 610065,Sichuan,China)

机构地区：[1]四川大学电子信息学院,四川成都610065

出　　处：《激光与光电子学进展》2023年第7期128-134,共7页Laser & Optoelectronics Progress

基　　金：国家自然科学基金(U20A20215,61875142);四川大学基金(2020SCUNG205)。

摘　　要：为了解决相位测量偏折术测量小曲率半径凸球面时相机所采集到的条纹图案边缘模糊、对比度低的问题,提出了基于逆光线追迹的预畸变条纹偏折术。该方法通过预设待测球面元件的曲率半径建立逆光线追迹模型来获得预畸变条纹图案。利用N步相移算法和迭代优化算法获得待测元件坐标和高度,再结合微分几何方法计算待测元件各点的平均曲率半径。在数值模拟中对曲率半径为8 mm的球面的测量精度约为11μm。最后,在实验中对曲率半径均值为8.26 mm凸球面上的各点进行测量得到的平均曲率半径为8.28 mm,测量区域的直径由原来的4 mm增加到5 mm。结果表明,相比于传统偏折术,本文方法不仅解决了偏折术测量曲率半径较小凸球面时条纹图案边缘模糊、对比度低的问题,还提高了测量精度、增大了有效测量面积。A pre-distortion fringe deflection approach based on reverse ray tracing was proposed to address the blurred edges and low contrast of the fringe pattern captured by the camera while measuring a convex sphere with a small radius of curvature(ROC)using phase measuring deflectometry.In this approach,the pre-distortion fringe pattern was obtained by employing the reverse ray tracing model based on the nominal ROC of the spherical element to be tested.N-step phase shift algorithm and iterative optimization algorithm were applied to obtain the coordinates and height of each point on the element surface and subsequently combine with the differential geometry approach to compute the mean ROC of each point of the element.For a convex surface with an ROC value of 8 mm,the measurement accuracy in numerical simulations was approximately 11μm.Finally,the mean ROC obtained for the points on the convex sphere with a ROC value of 8.26 mm was 8.28 mm,and the diameter of the measurement area increased from the original 4 mm to 5 mm.The findings reveal that compared with the traditional deflection approach,this approach can not only overcome the issue of blurred edge and low contrast of the fringe pattern when measuring convex spheres with small ROC but also improves the measurement accuracy and effective measurement area.

关 键 词：测量 相位测量偏折术 凸球面 小曲率半径 预畸变条纹 微分几何 

分 类 号：O436[机械工程—光学工程]