Reference

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fft

Built-in command

Arguments:

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

$ gmic 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

$ gmic 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]