傅立叶变换轮廓术测量范围的普适讨论

Analysis on Generalized Measuring Range of Fourier Transform Profilometry

针对目前傅立叶变换轮廓术(FTP)测量范围的公式仅适用于投影呈一维变化的光栅条纹的情况,对FTP的测量范围进行了更深入的讨论,给出了适用于投影呈二维变化的光栅条纹的普适的测量范围公式。得出了当被测物体的频谱呈现非圆形分布时,可以采用改变投影的光栅条纹的方向消除频谱混叠,达到在不增加条纹密度和图像获取装置的分辨率的情况下减小或消除基频和零频间的混叠。

At present, the analysis about maximum measuring range of Fourier transform profilometry (FTP) given by Takeda is fit for fringe pattern with single direction frequency carrier. When fringe pattern with two directions frequency carrier is projected onto the object, the limitation of measuring range have not been given. So the maximum measuring range of FTP projected this kind of fringe pattern was analyzed and an expression was given. It shows that we can avoid the frequency aliasing by changing the direction of the frequency carrier when the spectra distribution of the measured object is not spherical symmetry, without increasing the density of the projected fringe and resolution of CCD camera.