This script calculates the spatial frequency, amplitude, and phase of the peaks (i.e., bright spots) in the Fourier transform of an image,using sub-pixel interpolation. For the script to work correctly, the original image must have been multiplied by a Hanning window before the FFT was calculated.
Before running the script, use the rectangular selection tool to select one or more bright spots. The Shift-key must be held down when making multiple selections. The script outputs the data in rows containing the spatial frequency, amplitude, and phase. The data is tab-delimited to facilitate pasting into Excel etc.
The amplitudes and phases are calculated according to the equations in W.J. de Ruijter.
Journal of Computer-Assisted Microscopy, 6(4):195-212, 1994.