提高Fourier变换轮廓术测量精度的新方法

A New Method for Improving Measuring Accuracy of Fourier Transform Profilometry

在傅里叶变换轮廓术测量方法中,对离散的条纹进行DFT(离散傅里叶变换)运算,存在“栅 栏效应”,离散频谱不能完全无误地代表原连续频谱分布,相当于在频域内发生了谱信息损失。为了减小由“栅栏效应”引入的位相误差,采用了对条纹进行空域数值加权和外插补零方法,从而提高FTP的测量精度。计算机模拟证实了所提方法的有效性。

A 'fence effect' is existed in Discrete Fourier Transform (DFT) operation carried out for the discrete fringes in Fourier transform profilometry. The discrete Fourier spectrum cannot entirely represent the original continuous spectrum distribution. This corresponds to result in the loss of spectrum information in the frequency domain. In order to decrease the phase error introduced by 'fence effect', the measuring accuracy can be improved through numerically weighting for the fringes in spatial domain and extrapolation zero filling method. The computer simulation demonstrates the effectiveness of the proposed method.