159 lines
5.5 KiB
C
159 lines
5.5 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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* 2008-02-04 tcv:
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* - exp( i.th ) == cos(th)+i.sin(th) NOT sin(th)+i.cos(th)
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* - add quadratic version (ifdef'd out ATM - still using trigonometric one)
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*
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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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/* There doesn't seem to be much difference in speed between these two methods (on an Athlon64),
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* so I use the modulus argument version, since atan2() is in c89 but hypot() is c99.
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*
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* If you think that it might be faster on your platform, uncomment the following:
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*/
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#define USE_MODARG_DIV
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#ifdef USE_MODARG_DIV
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#define COMPLEX_PHASE_FN( TYPE, ABS ) \
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static void \
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complex_phase_ ## TYPE ( void *in1, void *in2, void *out, int n, void *im, void *unrequired ){ \
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\
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TYPE *X= (TYPE*) in1; \
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TYPE *Y= (TYPE*) in2; \
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TYPE *Z= (TYPE*) out; \
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TYPE *Z_stop= Z + 2 * n * ((IMAGE*)im)-> Bands; \
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\
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for( ; Z < Z_stop; X+= 2, Y+= 2 ){ \
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double arg= atan2( X[1], X[0] ) - atan2( Y[1], Y[0] ); \
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*Z++= cos( arg ); \
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*Z++= sin( arg ); \
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} \
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}
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#else /* USE_MODARG_DIV */
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#define COMPLEX_PHASE_FN( TYPE, ABS ) \
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static void \
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complex_phase_ ## TYPE ( void *in1, void *in2, void *out, int n, void *im, void *unrequired ){ \
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\
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TYPE *X= (TYPE*) in1; \
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TYPE *Y= (TYPE*) in2; \
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TYPE *Z= (TYPE*) out; \
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TYPE *Z_stop= Z + 2 * n * ((IMAGE*)im)-> Bands; \
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\
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for( ; Z < Z_stop; X+= 2, Y+= 2 ) \
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\
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if( ABS( Y[0] ) > ABS( Y[1] )){ \
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double a= Y[1] / Y[0]; \
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double b= Y[0] + Y[1] * a; \
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double re= ( X[0] + X[1] * a ) / b; \
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double im= ( X[1] - X[0] * a ) / b; \
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double mod= im__hypot( re, im ); \
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*Z++= re / mod; \
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*Z++= im / mod; \
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} \
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else { \
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double a= Y[0] / Y[1]; \
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double b= Y[1] + Y[0] * a; \
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double re= ( X[0] * a + X[1] ) / b; \
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double im= ( X[1] * a - X[0] ) / b; \
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double mod= im__hypot( re, im ); \
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*Z++= re / mod; \
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*Z++= im / mod; \
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} \
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}
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#endif /* USE_MODARG_DIV */
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COMPLEX_PHASE_FN( float, fabsf )
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COMPLEX_PHASE_FN( double, fabs )
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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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return im_cp_descv( out, a, b, NULL ) || im_wraptwo( a, b, out,
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IM_BANDFMT_COMPLEX == a-> BandFmt ? complex_phase_float : complex_phase_double, a, NULL );
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}
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