基于相位测量偏折术(PMD)测量原理，提出了一种简单、可靠、精度高的三维面形检测新方法，可以运用于非球面反射镜精磨与粗抛光阶段的面形检测。所提检测方法通过利用入射光线、小孔坐标，以及虚拟的辅助表面来得到待测反射镜面的绝对高度和梯度。测量时，在CCD 相机前放置一个小孔光阑来实现小孔成像模型，并以该小孔的位置作为相机的位置，同时利用相移法并通过移动LCD 显示屏一次，获得摄像机上每个像素点所对应的入射光线。该方法对实验设备的位置无特殊要求，不需要辅助器件，检测过程简单，检测结果可靠。而且，该检测方法采用虚拟的辅助表面对反射镜面进行检测而不是采用入射光线与反射光线的交点，不需要对相机光线进行标定，检测结果受标定误差的影响很小，所以该检测方法具有很高的检测精度。计算机仿真与初步实验验证了该方法的可行性。

A novel three-dimensional (3D) shape measuring method based on phase measuring deflectometry (PMD) is presented, which can be used to measure the aspheric mirror during the stages of fine grinding and the beginning of polish. The proposed method measures the absolute height and slope of the specular surface with incidence ray, camera pinhole and dummy assistant surfaces. During the measurement, a camera with an external stop is used to realize pinhole camera model. The external stop represents the position of the camera and the incidence ray corresponding to the pixels of the camera can be obtained by moving LCD screen once. The procedure of the test is simple and the result is believable because it has no restrict requirements for the experimental devices and no need of other auxiliary devices. What′s more, this method measures the specular surface with dummy auxiliary surfaces instead of the intersection of the incidence ray and the camera ray. So there is no need to calibrate the camera ray. This method can be used to test the specular surface with high pre ? cision because the calibration error has little effect on the result of the testing. Computer simulation and experi? ment validate the feasibility of the proposed method.