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/* im_fastcor
*
* Copyright: 1990, N. Dessipris.
*
* Author: Nicos Dessipris
* Written on: 02/05/1990
* Modified on : 15/03/1991
* 20/2/95 JC
* - ANSIfied
* - in1 and in2 swapped, to match order for im_spcor
* - memory leaks fixed
* 21/2/95 JC
* - partialed
* - speed-ups
* 7/4/04
* - now uses im_embed() with edge stretching on the output
* - sets Xoffset / Yoffset
* 8/3/06 JC
* - use im_embed() with edge stretching on the input, not the output
* - calculate sum of squares of differences, rather than abs of
* difference
* 3/2/10
* - gtkdoc
* - cleanups
*/
/*
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>
/* Fastcor generate function.
*/
static int
fastcor_gen( REGION *or, void *seq, void *a, void *b )
{
REGION *ir = (REGION *) seq;
IMAGE *ref = (IMAGE *) b;
Rect irect;
Rect *r = &or->valid;
int x, y, i, j;
int lsk;
/* What part of ir do we need?
*/
irect.left = or->valid.left;
irect.top = or->valid.top;
irect.width = or->valid.width + ref->Xsize - 1;
irect.height = or->valid.height + ref->Ysize - 1;
if( im_prepare( ir, &irect ) )
return( -1 );
lsk = IM_REGION_LSKIP( ir );
/* Loop over or.
*/
for( y = 0; y < r->height; y++ ) {
unsigned int *q = (unsigned int *)
IM_REGION_ADDR( or, r->left, r->top + y );
for( x = 0; x < r->width; x++ ) {
VipsPel *b = ref->data;
VipsPel *a =
IM_REGION_ADDR( ir, r->left + x, r->top + y );
int sum;
sum = 0;
for( j = 0; j < ref->Ysize; j++ ) {
for( i = 0; i < ref->Xsize; i++ ) {
int t = b[i] - a[i];
sum += t * t;
}
a += lsk;
b += ref->Xsize;
}
q[x] = sum;
}
}
return( 0 );
}
/* Raw fastcor, with no borders.
*/
int
im_fastcor_raw( IMAGE *in, IMAGE *ref, IMAGE *out )
{
/* PIO between in and out; WIO from ref.
*/
if( im_piocheck( in, out ) ||
im_incheck( ref ) )
return( -1 );
/* Check sizes.
*/
if( in->Xsize < ref->Xsize || in->Ysize < ref->Ysize ) {
im_error( "im_fastcor", "%s",
_( "ref not smaller than or equal to in" ) );
return( -1 );
}
/* Check types.
*/
if( im_check_uncoded( "im_fastcor", in ) ||
im_check_mono( "im_fastcor", in ) ||
im_check_format( "im_fastcor", in, IM_BANDFMT_UCHAR ) ||
im_check_coding_same( "im_fastcor", in, ref ) ||
im_check_bands_same( "im_fastcor", in, ref ) ||
im_check_format_same( "im_fastcor", in, ref ) )
return( -1 );
/* Prepare the output image.
*/
if( im_cp_descv( out, in, ref, NULL ) )
return( -1 );
out->BandFmt = IM_BANDFMT_UINT;
out->Xsize = in->Xsize - ref->Xsize + 1;
out->Ysize = in->Ysize - ref->Ysize + 1;
/* FATSTRIP is good for us, as THINSTRIP will cause
* too many recalculations on overlaps.
*/
if( im_demand_hint( out, IM_FATSTRIP, in, NULL ) ||
im_generate( out,
im_start_one, fastcor_gen, im_stop_one, in, ref ) )
return( -1 );
out->Xoffset = -ref->Xsize / 2;
out->Yoffset = -ref->Ysize / 2;
return( 0 );
}
/**
* im_fastcor:
* @in: input image
* @ref: reference image
* @out: output image
*
* Calculate a fast correlation surface.
*
* @ref is placed at every position in @in and the sum of squares of
* differences calculated. One-band, 8-bit unsigned images only. The output
* image is always %IM_BANDFMT_UINT. @ref must be smaller than or equal to
* @in. The output
* image is the same size as the input.
*
* See also: im_spcor().
*
* Returns: 0 on success, -1 on error
*/
int
im_fastcor( IMAGE *in, IMAGE *ref, IMAGE *out )
{
IMAGE *t1 = im_open_local( out, "im_fastcor intermediate", "p" );
if( !t1 ||
im_embed( in, t1, 1,
ref->Xsize / 2, ref->Ysize / 2,
in->Xsize + ref->Xsize - 1,
in->Ysize + ref->Ysize - 1 ) ||
im_fastcor_raw( t1, ref, out ) )
return( -1 );
out->Xoffset = 0;
out->Yoffset = 0;
return( 0 );
}
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