基于相移偏折法的高反射表面面形测量技术

Measurement Technique of High-reflected Surface Based on Phase Measuring Deflectometry

利用单相机所采集的图像实现了对光滑高反射表面面形的直接检测.首先利用相机获取参考平面在标准平面镜中的镜像,然后通过参考平面上的点与归一化成像平面上图像点之间的密集折返对应关系,求得待测镜面的深度距离,从而实现对高反射表面面形的测量.通过光线追迹将该测量过程转化为求解物空间中关于两对应光线束之间的相交问题.以相位为载体获取面形梯度分布,求得该表面的法向量场,并求解相应的反射光线束.通过光线追迹对该光线束与相应入射光线束求“交点”检测高反射表面.对标准平面镜进行实验检测,测量得到的面形平面度为0.19 mm.采用传统方法与本文所提方法对汽车后视镜进行检测,所得检测结果对应点之间的平均距离为0.15 mm,验证了本文方法检测镜面面形的有效性.

The direct measurement of the smooth and high-reflected surface was realized using images acquired by a single camera.Firstly,the image of the reference plane in the standard plane mirror was captured by the camera.Then,the depth distance of the mirror to be measured was obtained,by using the dense reflection correspondence between the points on the reference plane and the image points on the normalized imaging plane.Finally,the measurement of high-reflected surface was achieved.The high-reflected surface was measured by finding the"intersection point"between the camera ray beam and the corresponding incident ray beam.The ray tracing was used to transform the measurement process into an intersection problem between the two corresponding ray bundles in the solution space.The normal fields of the surface were obtained and the corresponding reflected light beam was solved based on the surface profile gradient which is obtained by taking the phase information as the carrier.The standard plane mirror is tested and the measured flatness is 0.19 mm.The rearview mirror is detected by the traditional method and the method proposed in this paper,and the average distance between the corresponding points in the test result is 0.15 mm,which verifies the effectiveness of the method for detecting the mirror surface shape.