New Method to Improve Range and Precision of 3D Surface Measurement

摘要

We introduce short-time Fourier transform into Fourier transform profilometry(FTP) to extract zero frequency component included in deformed fringe pattern. This method can be used to eliminate zero component by only one deformed fringe pattern instead of two. First we extract zero component of deformed fringe image using short-time Fourier transform and normalize it, then calculate the normalized Fourier spectra of deformed fringe image, finally subtract the zero component from Fourier spectra Fourier spectra of deformed fringe image. We give the theory analysis. Experimental results verify that this method can eliminate zero component and extend the measuring range of Fourier transform profilometry to nearly three times of that of the traditional FTP using a frame deformed fringe image. So it is an efficient method to extend measuring range and keep measuring speed, and the setup is very simple because of no phase shifting device needed.