G'MIC - GREYC's Magic for Image Computing: A Full-Featured Open-Source Framework for Image Processing
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A Full-Featured Open-Source Framework for Image Processing

Latest stable version: 3.5.5        Current pre-release: 3.6.0 (2025/08/04)

Reference
Table of Contents  ▸  List of Commands  ▸  Filtering  ▸  fft◀  erode_threshold    |    gradient  ▶

fft

Built-in command

Arguments:

  • _{ x | y | z }...{ x | y | z }

Description:

Compute the direct fourier transform (real and imaginary parts) of selected images,

optionally along the specified axes only.

See also:

ifft.

This command has a tutorial page.

Examples of use:

• Example #1

image.jpg luminance +fft append[-2,-1] c norm[-1] log[-1] shift[-1] 50%,50%,0,0,2

Command: image.jpg luminance +fft append[-2,-1] c norm[-1] log[-1] shift[-1] 50%,50%,0,0,2
Command: image.jpg luminance +fft append[-2,-1] c norm[-1] log[-1] shift[-1] 50%,50%,0,0,2

• Example #2

image.jpg w2:=int(w/2) h2:=int(h/2) fft shift $w2,$h2,0,0,2 ellipse $w2,$h2,30,30,0,1,0 shift -$w2,-$h2,0,0,2 ifft remove[-1]

Command: image.jpg w2:=int(w/2) h2:=int(h/2) fft shift $w2,$h2,0,0,2 ellipse $w2,$h2,30,30,0,1,0 shift -$w2,-$h2,0,0,2 ifft remove[-1]
G'MIC - GREYC's Magic for Image Computing: A Full-Featured Open-Source Framework for Image Processing

G'MIC is an open-source software distributed under the CeCILL free software licenses (LGPL-like and/or
GPL-compatible). Copyrights (C) Since July 2008, David Tschumperlé - GREYC UMR CNRS 6072, Image Team.