libvips/libsrc/freq_filt/im_freqflt.c

125 lines
3.4 KiB
C

/* @(#) Functions which takes as input a valid image and filters it
* @(#) in the fourier domain with the filter mask
* @(#) Input can have any format ; output is the same as input
* @(#) imin can be char uchar, short, ushort, int, uint, float, double
* @(#) or complex float; result is the same as input, clipped if necessary.
* @(#) mask can have any format but the sizes of input and mask are equal
* @(#) The function performs float fft and if the input is not complex float
* @(#) the output is casted to the type of input according to im_clip2..()
* @(#) Since buffer images are involved the size, is restricted to 512x512
* @(#) for the SUN4 SPARC workstation
* @(#)
* @(#) int im_freqflt(imin, mask, imout)
* @(#) IMAGE *imin, *mask, *imout;
* @(#)
* @(#) Returns 0 on success and -1 on error
*
* Copyright: 1990, N. Dessipris.
*
* Author: Nicos Dessipris
* Written on: 02/05/1990
* Modified on : 08/03/1991
* 16/6/93 J.Cupitt
* - im_multiply() called, rather than im_cmultim()
* 27/10/93 JC
* - im_clip2*() called, rather than im_any2*()
* 20/9/95 JC
* - rewritten
* 10/9/98 JC
* - frees memory more quickly
* 4/3/03 JC
* - use im_invfftr() to get real back for speedup
*/
/*
This file is part of VIPS.
VIPS is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/*
These files are distributed with VIPS - http://www.vips.ecs.soton.ac.uk
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif /*HAVE_CONFIG_H*/
#include <vips/intl.h>
#include <stdio.h>
#include <math.h>
#include <vips/vips.h>
#ifdef WITH_DMALLOC
#include <dmalloc.h>
#endif /*WITH_DMALLOC*/
int
im_freqflt( IMAGE *in, IMAGE *mask, IMAGE *out )
{
IMAGE *dummy;
/* Placeholder for memory free.
*/
if( !(dummy = im_open( "memory-1", "p" )) )
return( -1 );
if( im_iscomplex( in ) ) {
/* Easy case! Assume it has already been transformed.
*/
IMAGE *t1 = im_open_local( dummy, "im_freqflt-1", "p" );
if( !t1 ||
im_multiply( in, mask, t1 ) ||
im_invfftr( t1, out ) ) {
im_close( dummy );
return( -1 );
}
}
else {
/* Harder - fft first, then mult, then force back to start
* type.
*
* Optimisation: output of im_invfft() is float buffer, we
* will usually chagetype to char, so rather than keeping a
* large float buffer and partial to char from that, do
* changetype to a memory buffer, and copy to out from that.
*/
IMAGE *t[3];
IMAGE *t3;
if( im_open_local_array( dummy, t, 3, "im_freqflt-1", "p" ) ||
!(t3 = im_open_local( out, "im_freqflt-3", "t" )) ||
im_fwfft( in, t[0] ) ||
im_multiply( t[0], mask, t[1] ) ||
im_invfftr( t[1], t[2] ) ||
im_clip2fmt( t[2], t3, in->BandFmt ) ||
im_copy( t3, out ) ) {
im_close( dummy );
return( -1 );
}
}
im_close( dummy );
return( 0 );
}