Study on influential factors of measurement precision using Fourier transform profilometry

This paper investigated the effects of various factors on measurement precision using Fourier transform profilometry (FTP). The spherical cap profile was tested by FTP. Firstly, the profiles under different grating frequencies and incident angles were investigated in order to examine the effects of grating frequency and incident angle on measurement precision and acquire suitable grating frequency and incident angle. Further, random speckles were added on the surface of spherical cap, and its profiles under the conditions with different speckle numbers and sizes were measured for exploring their effect on the measurement precision. Finally, different filtering methods were adopted for testing the spherical cap profile with random speckles and based on the results an effective improvement method was proposed. In conclusion, this study found some factors determining the measurement precision using FTP and proposed some effective schemes for its improvement, which were helpful to the application of FTP.