提出一种基于相位偏折术(PMD)的非球面镜检测方法。在条纹屏上显示标准正弦环形条纹,经过被测镜反射后为相机所接收。通过对两次不同位置的条纹平面进行测量,利用相移技术及相位展开技术得到两次位置处的相位分布,从而得到像素点对应的原始光线和偏折光线的位置和方向,确定光线的偏折位置和角度,计算出被测面形的梯度分布,通过数值积分重建被测面形。该方法具有结构简单、成本低、易于实行和动态测量范围较大的特点,可用于加工过程中波前变化范围较大的非球面反射镜精磨和初抛光阶段的检验。数字模拟和实验验证了这一技术的可行性。

A method based on basic phase measuring deflectometry (PMD) is proposed for testing the aspherical mirror,which uses two reference screens in different distances from the tested mirror. The intensity-modulated patterns are generated on the screens and the images reflected via the tested mirror are recorded by a camera. The original ray of every pixel and its corresponding deflected ray can be constructed using the recorded patterns and phase-shifting technique. Their intersection points and the surface normal are obtained. Then the mirror surface is reconstructed by numerical integration. The procedure for this method is presented,and the computer simulation and experimental results are shown.