针对传统傅里叶变换法处理光载波干涉条纹图时会有边缘效应产生的问题,提出了一种以傅里叶位移定理为依据的外推延拓方法,数值仿真的结果表明这一方法可以很好地抑制边缘效应所造成的较大误差,使相位的计算精度达到3.3 mrad。为了检验这一方法的正确性,设计了环路径向剪切干涉系统,测量了透过平凸透镜的激光波面,并与传统的离散傅里叶变换的方法进行了比较。结果表明使用这一方法可以使测量精度提高一个数量级。

There are noticeable errors at the border of the pattern when the traditional Fourier transform method (FTM) is used to evaluate the carrier fringe pattern. A new extrapolation of fringe prolongation method based on the shift theorem of Fourier transform is proposed. Numerical simulations are performed to evaluate the performance of the method which reduces the errors at the borders of the pattern. An accuracy of the phase evaluation of approximately 3.3 mrad is obtained. In order to verify the methode, a radial shearing interferometer system has been set up. The surface of a plano-convex lens has been measured. Wavefront traversing the sample is reconstructed by means of the new extrapolation method of fringe prolongation. The results show that errors are reduced in the processing of shearing wavefront testing.