Interferograms analysis for wavelength scanning interferometer using convolution and fourier transform.

A convolution and fast Fourier transform methods are proposed separately to analysis a set of interferograms obtained from measurement results of a wavelength scanning interferometer. This paper describes wavelength scanning interferometer setup and the operation principle. Mathematical explanations, for both interferograms analysis methods, are presented. Results of measuring 3μm step height sample, using both interferograms analysis methods, are demonstrated. The results show that the convolution method provides better evaluation for the surface profile than the fast Fourier transform