滤波窗的选择对傅里叶变换轮廓术测量精度的影响

Analysis on measuring accuracy of Fourier transform profilometry due to different filtering window

比较了在有噪声和无噪声的情况下 ,傅里叶变换轮廓术中采用三种频域滤波窗对测量精度的影响。给出了在有噪声和无噪声情况下 ,FTP中采用不同滤波窗的测量误差分布图。得出在无噪声及噪声较小的情况下 ,采用平顶高斯滤波窗测量面形精度最高 ,而在噪声较大的情况下 ,采用汉宁滤波窗测量面形精度最高。

In Fourier transform profilometry.a grating pattern projected onto the object surface is Fourier-transformed and processed in its spatial frequency domain.To reconstruct the height distribution of object surface.the underlying phase distribution should be extracted form founclamental spectrum of fringe pattern.Hanning,Gaussian and Rect filter are usually in FTP to obtain fundamental spectra.In this paper we analyze the accuracy of FTP using these kinds of fliter when noise exists and does not exist.We also give the error distrbution without noise and with noise.This paper gives a conclusion that using flattened Gaussian window got the best measuring accuracy at low levels of added noise and without noise,while using Hanning window got the best measuring accuracy at high levels of added noise