fhtPower
[ XITE Reference Manual | XITE home ]
Name
fhtPower - calculate power specter from Hartley transform
Syntax
#include <xite/fht.h>
int fhtPower( IR_BAND inband, IR_BAND outband );
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
Restrictions
Bands should have equal size. Currently, only single
precision float values are accepted.
See also
fhtPower(1), fht2d(3), fft2d(3), ft2ht(3), ht2ft(3),
fhtPhase(3)
Return value
0 => ok
1 => bad pixel type input
2 => bad pixel type output
3 => bad sizes
Author
Tor Lønnestad, BLAB, Ifi, UiO
Id
$Id: fhtPower.c,v 1.24 1997/05/27 14:48:33 svein Exp $