Surface Profile Interferometry Using FFT and Selecting a Frequency Region

[AjayShankar]

I am trying to use use LabVIEW and Vision to extract surface profile extracting phase information encoded in interference fringes taken for that surface. I read the pattern select particular region take its FFT and select one FFT spectral zone from the fringe. I am following a article " Fourier Tarnsform Profilometry in LabVIEW (Attached) which suggest using using Hanning Filter which I have tried to generate. After selecting second ROI from FFT pattern it shows wrong Image and not running. I am not able to fix it so if anydody can help debugging this VI.

[Mason_Ho]

I don't understand FFT. But I replace "IMAQ Extract Tetragon VI" with "IMAQ ComplexImageToArray VI", then it work fine.