libvips/libvips/convolution/spcor.c

382 lines
9.1 KiB
C

/* spcor
*
* Copyright: 1990, N. Dessipris; 2006, 2007 Nottingham Trent University.
*
*
* Author: Nicos Dessipris
* Written on: 02/05/1990
* Modified on :
* 20/2/95 JC
* - updated
* - ANSIfied, a little
* 21/2/95 JC
* - rewritten
* - partialed
* - speed-ups
* - new correlation coefficient (see above), from Niblack "An
* Introduction to Digital Image Processing", Prentice/Hall, pp 138.
* 4/9/97 JC
* - now does short/ushort as well
* 13/2/03 JC
* - oops, could segv for short images
* 14/4/04 JC
* - sets Xoffset / Yoffset
* 8/3/06 JC
* - use im_embed() with edge stretching on the input, not the output
*
* 2006-10-24 tcv
* - add im_spcor2
*
* 2007-11-12 tcv
* - make im_spcor a wrapper selecting either im__spcor or im__spcor2
* 2008-09-09 JC
* - roll back the windowed version for now, it has some tile edge effects
* 3/2/10
* - gtkdoc
* - cleanups
* 7/11/13
* - redone as a class
* 8/4/15
* - avoid /0 for constant reference or zero image
*/
/*
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., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 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 <glib/gi18n-lib.h>
#include <stdio.h>
#include <math.h>
#include <vips/vips.h>
#include "pconvolution.h"
#include "correlation.h"
typedef struct _VipsSpcor {
VipsCorrelation parent_instance;
/* Per-band mean of ref images.
*/
double *rmean;
/* Per band sqrt(sumij (ref(i,j)-mean(ref))^2)
*/
double *c1;
} VipsSpcor;
typedef VipsCorrelationClass VipsSpcorClass;
G_DEFINE_TYPE( VipsSpcor, vips_spcor, VIPS_TYPE_CORRELATION );
static int
vips_spcor_pre_generate( VipsCorrelation *correlation )
{
VipsObjectClass *class = VIPS_OBJECT_GET_CLASS( correlation );
VipsSpcor *spcor = (VipsSpcor *) correlation;
VipsImage *ref = correlation->ref_ready;
int bands = ref->Bands;
VipsImage **b = (VipsImage **)
vips_object_local_array( VIPS_OBJECT( spcor ), bands );
VipsImage **t = (VipsImage **)
vips_object_local_array( VIPS_OBJECT( spcor ), 2 );
VipsImage **b2 = (VipsImage **)
vips_object_local_array( VIPS_OBJECT( spcor ), bands );
int i;
double *offset;
double *scale;
if( vips_check_noncomplex( class->nickname, ref ) )
return( -1 );
/* Per-band mean.
*/
if( !(spcor->rmean = VIPS_ARRAY( spcor, bands, double )) ||
!(spcor->c1 = VIPS_ARRAY( spcor, bands, double )) )
return( -1 );
for( i = 0; i < bands; i++ )
if( vips_extract_band( ref, &b[i], i, NULL ) ||
vips_avg( b[i], &spcor->rmean[i], NULL ) )
return( -1 );
/* Per band sqrt(sumij (ref(i,j)-mean(ref))^2)
*/
if( !(offset = VIPS_ARRAY( spcor, bands, double )) ||
!(scale = VIPS_ARRAY( spcor, bands, double )) )
return( -1 );
for( i = 0; i < bands; i++ ) {
offset[i] = -spcor->rmean[i];
scale[i] = 1.0;
}
if( vips_linear( ref, &t[0], scale, offset, bands, NULL ) ||
vips_multiply( t[0], t[0], &t[1], NULL ) )
return( -1 );
for( i = 0; i < bands; i++ )
if( vips_extract_band( t[1], &b2[i], i, NULL ) ||
vips_avg( b2[i], &spcor->c1[i], NULL ) )
return( -1 );
for( i = 0; i < bands; i++ ) {
spcor->c1[i] *= ref->Xsize * ref->Ysize;
spcor->c1[i] = sqrt( spcor->c1[i] );
}
return( 0 );
}
#define LOOP( IN ) { \
IN *r1 = ((IN *) ref->data) + b; \
IN *p1 = ((IN *) p) + b; \
int in_lsk = lsk / sizeof( IN ); \
IN *r1a; \
IN *p1a; \
\
/* Mean of area of in corresponding to ref. \
*/ \
p1a = p1; \
sum1 = 0.0; \
for( j = 0; j < ref->Ysize; j++ ) { \
for( i = 0; i < sz; i += bands ) \
sum1 += p1a[i]; \
p1a += in_lsk; \
} \
imean = sum1 / VIPS_IMAGE_N_PELS( ref ); \
\
/* Calculate sum-of-squares-of-differences for this window on \
* in, and also sum-of-products-of-differences from mean. \
*/ \
p1a = p1; \
r1a = r1; \
sum2 = 0.0; \
sum3 = 0.0; \
for( j = 0; j < ref->Ysize; j++ ) { \
for( i = 0; i < sz; i += bands ) { \
/* Reference pel and input pel. \
*/ \
IN ip = p1a[i]; \
IN rp = r1a[i]; \
\
/* Accumulate sum-of-squares-of-differences for \
* input image. \
*/ \
double t = ip - imean; \
sum2 += t * t; \
\
/* Accumulate product-of-difference from mean. \
*/ \
sum3 += (rp - spcor->rmean[b]) * t; \
} \
\
p1a += in_lsk; \
r1a += sz; \
} \
}
static void
vips_spcor_correlation( VipsCorrelation *correlation,
VipsRegion *in, VipsRegion *out )
{
VipsSpcor *spcor = (VipsSpcor *) correlation;
VipsRect *r = &out->valid;
VipsImage *ref = correlation->ref_ready;
int bands = vips_band_format_iscomplex( ref->BandFmt ) ?
ref->Bands * 2 : ref->Bands;
int sz = ref->Xsize * bands;
int lsk = VIPS_REGION_LSKIP( in );
int x, y, b, j, i;
double imean;
double sum1;
double sum2, sum3;
double c2, cc;
for( y = 0; y < r->height; y++ ) {
float *q = (float *)
VIPS_REGION_ADDR( out, r->left, r->top + y );
for( x = 0; x < r->width; x++ ) {
VipsPel *p =
VIPS_REGION_ADDR( in, r->left + x, r->top + y );
for( b = 0; b < bands; b++ ) {
switch( vips_image_get_format( ref ) ) {
case VIPS_FORMAT_UCHAR:
LOOP( unsigned char );
break;
case VIPS_FORMAT_CHAR:
LOOP( signed char );
break;
case VIPS_FORMAT_USHORT:
LOOP( unsigned short );
break;
case VIPS_FORMAT_SHORT:
LOOP( signed short );
break;
case VIPS_FORMAT_UINT:
LOOP( unsigned int );
break;
case VIPS_FORMAT_INT:
LOOP( signed int );
break;
case VIPS_FORMAT_FLOAT:
case VIPS_FORMAT_COMPLEX:
LOOP( float );
break;
case VIPS_FORMAT_DOUBLE:
case VIPS_FORMAT_DPCOMPLEX:
LOOP( double );
break;
default:
g_assert_not_reached();
/* Stop compiler warnings.
*/
sum2 = 0;
sum3 = 0;
}
c2 = spcor->c1[b] * sqrt( sum2 );
if( c2 == 0.0 )
/* Something like constant ref.
* We regard this as uncorrelated.
*/
cc = 0.0;
else
cc = sum3 / c2;
*q++ = cc;
}
}
}
}
/* Save a bit of typing.
*/
#define UC VIPS_FORMAT_UCHAR
#define C VIPS_FORMAT_CHAR
#define US VIPS_FORMAT_USHORT
#define S VIPS_FORMAT_SHORT
#define UI VIPS_FORMAT_UINT
#define I VIPS_FORMAT_INT
#define F VIPS_FORMAT_FLOAT
#define X VIPS_FORMAT_COMPLEX
#define D VIPS_FORMAT_DOUBLE
#define DX VIPS_FORMAT_DPCOMPLEX
static const VipsBandFormat vips_spcor_format_table[10] = {
/* Band format: UC C US S UI I F X D DX */
/* Promotion: */ F, F, F, F, F, F, F, F, F, F
};
static void
vips_spcor_class_init( VipsSpcorClass *class )
{
VipsObjectClass *object_class = (VipsObjectClass *) class;
VipsCorrelationClass *cclass = VIPS_CORRELATION_CLASS( class );
object_class->nickname = "spcor";
object_class->description = _( "spatial correlation" );
cclass->format_table = vips_spcor_format_table;
cclass->pre_generate = vips_spcor_pre_generate;
cclass->correlation = vips_spcor_correlation;
}
static void
vips_spcor_init( VipsSpcor *spcor )
{
}
/**
* vips_spcor: (method)
* @in: input image
* @ref: reference image
* @out: (out): output image
* @...: %NULL-terminated list of optional named arguments
*
* Calculate a correlation surface.
*
* @ref is placed at every position in @in and the correlation coefficient
* calculated. The output
* image is always float.
*
* The output
* image is the same size as the input. Extra input edge pixels are made by
* copying the existing edges outwards.
*
* The correlation coefficient is calculated as:
*
* |[
* sumij (ref(i,j)-mean(ref))(inkl(i,j)-mean(inkl))
* c(k,l) = ------------------------------------------------
* sqrt(sumij (ref(i,j)-mean(ref))^2) *
* sqrt(sumij (inkl(i,j)-mean(inkl))^2)
* ]|
*
* where inkl is the area of @in centred at position (k,l).
*
* from Niblack "An Introduction to Digital Image Processing",
* Prentice/Hall, pp 138.
*
* If the number of bands differs, one of the images
* must have one band. In this case, an n-band image is formed from the
* one-band image by joining n copies of the one-band image together, and then
* the two n-band images are operated upon.
*
* The output image is always float, unless either of the two inputs is
* double, in which case the output is also double.
*
* See also: vips_fastcor().
*
* Returns: 0 on success, -1 on error
*/
int
vips_spcor( VipsImage *in, VipsImage *ref, VipsImage **out, ... )
{
va_list ap;
int result;
va_start( ap, out );
result = vips_call_split( "spcor", ap, in, ref, out );
va_end( ap );
return( result );
}