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| File Edit Options Process Analyze Video Macros Stacks SEM SPM Windows Help |
Sharpen Shadow Find Edges Rank Filters Dither Convolve PlugIn Filters
Enhance Contrast Equalize Fix Colors Differential Curvature Unsharp Mask Hough Transform |
FFT Inverse FFT Display Power Spectrum Swap Quadrants Select Largest Square Select Longest Line Autocorrelation Make LEED into FFT Inverse FFT of LEED |
Computes the
Fourier transform and displays the power spectrum. Requires a square,
power of two size image or selection. The transformed frequency domain
image is stored in a 32-bit real buffer attached to the window
displaying the power spectrum. The only commands in NIH Image that currently recognize
this real image are Inverse FFT, Redisplay Power Spectrum and Image Math. All other commands "see" only
the 8-bit power spectrum. A helpful trick to remember when attempting
to make power of two sized selections is to hold down the shift key,
which forces the selection to be square.
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Steve Barrett November 2014 |
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