Suppressing inherent noise by combining different frequency peaks in Fourier transform profilometry

Abstract

In this paper we determined the height of a cylindrical phase using Fourier transform profilometry from different frequency peaks produced under a Ronchi grating illumination. The frequency peaks were individually filtered from the Fourier transform plane and their inverse Fourier transforms are calculated. Using Fourier transform profilometry we were able to obtain the maximum height and the average noise of each of the height distributions of the cylindrical phase. The following height distributions were averaged and their maximum height and noise values were compared with their uncombined counterparts. It was observed that for some combinations of peak frequencies, noise can be suppressed. In addition, no noise amplification occurred for all combinations, as well as height corrections. However, we could not predict which frequency peak combinations would give a height distribution with suppressed noise, as well as improved height corrections.