fhtPower
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Name
fhtPower - calculate power spectrum from Hartley transform
Syntax
fhtPower [-t <title>] <inimage> <outimage>
Description
fhtPower calculates the power spectrum from a
Hartley transform. The power spectrum is identical
to the power spectrum calculated from the Fourier
transform, and the Hartley transform is significantly
faster.
The power spectrum is
P(u,v) = [Re{F(u,v)}]^2 + [Im{F(u,v)}]^2
= H_e(u,v)^2 + H_o(u,v)^2
= (H(u,v)^2 + H(-u,-v)^2)/2
For images with horizontal and vertical even symmetry,
the power spectrum simplifies to
P(u,v) = ( H(u,v)^2 + H(-u,-v)^2 ) / 2
= H(u,v)^2
See also
fhtPower(3), fht2d(1), fft2d(1), ft2ht(1), ht2ft(1),
fhtPhase(1)
Restrictions
Input must be a single precision hartley 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
fhtPower monah.img monaf.img
Id
$Id: fhtPower.c,v 1.24 1997/05/27 14:48:33 svein Exp $