ft2ht
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Name
ft2ht - 2d fourier to hartley conversion
Syntax
ft2ht [-t <title>] <inimage> <outimage>
Description
ft2ht transforms a (single precision) complex Fourier
transform to a (single precision) real Hartley transform.
Note that the Hartley transform is faster than Fourier.
If you need Fourier it may be faster to compute the
Hartley transform and then convert to Fourier by means
of ht2ft.
The Hartley transform is given by the Fourier transform
as follows:
H(u,v) = Re{F(u,v)} - Im{F(u,v)}
= H_e(u,v) + H_o(u,v)
where H_e and H_o are the even and odd parts of H, i.e.
H_e(u,v) = (H(u,v) + H(-u,-v))/2
H_o(u,v) = (H(u,v) - H(-u,-v))/2
For images with horizontal and vertical even symmetry,
H_o(u,v) equals zero, so that
H(u,v) = F(u,v)
See also
ft2ht(3), fft2d(1), fht2d(1), ht2ft(1)
Restrictions
input image should be a sigle precision complex fourier
transform.
Return value
0 => ok
1 => bad number of arguments
2 => couldn't read input file
3 => couldn't write output file
Author
Tor Lønnestad, BLAB, Ifi, UiO
Examples
ft2ht monaf.img monah.img
Id
$Id: ft2ht.c,v 1.25 1997/05/27 14:48:34 svein Exp $