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FFT2D
Section: User Commands (1)
Updated: 16 Mar 1998
Index
NAME
fft2d - Two dimensional Fourier Transform
SYNTAX
fft2d [<option>...] <inimage> <outimage>
DESCRIPTION
fft2d performs a 2 dimensional Fourier transform.
If inimageis of another pixeltype than single precisioncomplex, inimagewill be converted to single precisioncomplex. When inimageis double precision complex, thisis only allowed when using option -rbelow.
The forward and inverse discrete Fourier transformswith standard scaling are given respectively as:
1 M N -j*2*pi*(ux/M + vy/N)
F(u,v) = --- Sum Sum f(x,y) e
M*N x=0 y=0
M N j*2*pi*(ux/M + vy/N)
f(x,y) = Sum Sum F(u,v) e
u=0 v=0
where M=Ixsize(f), N=Iysize(f).
RESTRICTIONS
Horizontal and vertical image size must be powers of two.
OPTIONS
- -i
- Inverse Fourier transform.
- -s scale, -fftscale scale
- The output image is multiplied by scale.Default scaleis1/(xsize*ysize) for forward transform and 1.0 for inversetransform.
- -b
- Pixeltype for outimagewill be unsigned byte, throughconversion of the result. Values outside the range of unsignedbyte will be limited to the min/max values for unsigned byte.
Default: Complex.
- -r
- Allow pixeltype of inimageto be double complex. Convertimage to pixeltype complex before applying the Fouriertransform.
Default: Allow only single-precision complex or non-complexpixeltype for inimage,not double complex. Convert theimage to pixeltype complex before applying the Fouriertransform.
RETURN VALUE
0 - ok
1 - error
SEE ALSO
fft2d(3),
absValue(1),
power(1),
phase(1),
real(1),
imag(1),
fftMagPhase(1),
multiply(1)
AUTHOR
Otto Milvang
ID
$Id: fft2d.c,v 1.34 1997/05/25 11:55:32 svein Exp $
Index
- NAME
- SYNTAX
- DESCRIPTION
- RESTRICTIONS
- OPTIONS
- RETURN VALUE
- SEE ALSO
- AUTHOR
- ID
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