139 lines
4.0 KiB
C
139 lines
4.0 KiB
C
/* @(#) Find the phase of the cross power spectrum of two complex images,
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* @(#) expressed as a complex image where the modulus of each pixel is
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* @(#) one.
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* @(#)
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* @(#) I.E. find (a.b*)/|a.b*| where
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* @(#) . represents complex multiplication
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* @(#) * represents the complex conjugate
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* @(#) || represents the complex modulus
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* @(#)
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* @(#) int im_cross_phase( IMAGE *a, IMAGE *b, IMAGE *out );
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* @(#)
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* @(#) All functions return 0 on success and -1 on error
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* @(#)
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*
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* Copyright: 2008, Nottingham Trent University
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*
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* Author: Tom Vajzovic
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* Written on: 2008-01-09
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*/
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/*
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This file is part of VIPS.
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VIPS is free software; you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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/*
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These files are distributed with VIPS - http://www.vips.ecs.soton.ac.uk
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*/
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#ifdef HAVE_CONFIG_H
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#include <config.h>
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#endif /*HAVE_CONFIG_H*/
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#include <vips/intl.h>
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#include <stdlib.h>
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#include <math.h>
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#include <vips/vips.h>
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#ifdef WITH_DMALLOC
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#include <dmalloc.h>
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#endif /*WITH_DMALLOC*/
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static void double_complex_phase( void *in1, void *in2, void *out, int n, void *im, void *unrequired );
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static void float_complex_phase( void *in1, void *in2, void *out, int n, void *im, void *unrequired );
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int im_cross_phase( IMAGE *a, IMAGE *b, IMAGE *out ){
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#define FUNCTION_NAME "im_phase"
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if( im_pincheck( a ) || im_pincheck( b ) || im_poutcheck( out ))
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return -1;
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if( a-> Xsize != b-> Xsize || a-> Ysize != b-> Ysize ){
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im_error( FUNCTION_NAME, "not same size" );
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return -1;
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}
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if( a-> Bands != b-> Bands ){
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im_error( FUNCTION_NAME, "numbers of bands differ" );
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return -1;
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}
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if( a-> Coding || b-> Coding ){
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im_error( FUNCTION_NAME, "not uncoded" );
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return -1;
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}
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if( a-> BandFmt != b-> BandFmt ){
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im_error( FUNCTION_NAME, "formats differ" );
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return -1;
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}
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if( IM_BANDFMT_COMPLEX != a-> BandFmt && IM_BANDFMT_DPCOMPLEX != a-> BandFmt ){
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im_error( FUNCTION_NAME, "not complex format" );
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return -1;
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}
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if( im_cp_descv( out, a, b, NULL )
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|| im_wraptwo( a, b, out,
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IM_BANDFMT_COMPLEX == a-> BandFmt ? float_complex_phase : double_complex_phase, a, NULL ))
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return -1;
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return 0;
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}
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static void double_complex_phase( void *in1, void *in2, void *out, int n, void *im, void *unrequired ){
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double *a= (double*) in1;
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double *b= (double*) in2;
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double *o= (double*) out;
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double *o_end= o + 2 * n * ((IMAGE*)im)-> Bands;
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for( ; o < o_end; a+= 2, b+= 2 ){
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double arg= atan2( a[1], a[0] ) - atan2( b[1], b[0] );
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*o++= sin( arg );
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*o++= cos( arg );
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#if 0
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/* FIXME very prone to overflow */
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double re= a[0] * b[0] + a[1] * b[1];
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double im= a[1] * b[0] - a[0] * b[1];
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double mod= hypot( re, im );
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*o++= re / mod;
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*o++= im / mod;
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#endif
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}
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}
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static void float_complex_phase( void *in1, void *in2, void *out, int n, void *im, void *unrequired ){
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float *a= (float*) in1;
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float *b= (float*) in2;
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float *o= (float*) out;
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float *o_end= o + 2 * n * ((IMAGE*)im)-> Bands;
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for( ; o < o_end; a+= 2, b+= 2 ){
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double arg= atan2( a[1], a[0] ) - atan2( b[1], b[0] );
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*o++= sin( arg );
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*o++= cos( arg );
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#if 0
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/* FIXME very prone to overflow */
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double re= (double)a[0] * (double)b[0] + (double)a[1] * (double)b[1];
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double im= (double)a[1] * (double)b[0] - (double)a[0] * (double)b[1];
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double mod= hypot( re, im );
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*o++= re / mod;
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*o++= im / mod;
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#endif
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}
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}
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