A white-light profiling algorithm adopting the multiwavelength interferometric technique

摘要

A new profiling algorithm is proposed for the scanning white-light interferometry. A series of white-light interferograms are acquired by traditional vertical scanning process. The collected intensity data of the interferograms are then Fourier-Transformed with respect to the ordinate, or the scanning axis, into the wave number domain, where two or more wave numbers are selected for further calculation. The multi-wavelength phase-unwrapping technique is then used to solve for the surface profile. Preliminary experiment has been carried out with a Mirau-type white-light interferometer on two sets of step-height standards. The proposed algorithm works as well even when the spectrum of the white-light source is not Gaussian distributed, while the conventional peak sensing algorithms do not.