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fix cos<->sin transposition in im_cross_phase

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This commit is contained in:
John Cupitt 2008-02-04 12:56:55 +00:00
parent 68328c9647
commit 9410ec047f
1 changed files with 75 additions and 55 deletions
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130
libsrc/arithmetic/im_cross_phase.c
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@ -1,9 +1,9 @@
/* @(#) Find the phase of the cross power spectrum of two complex images, /* @(#) Find the phase of the cross power spectrum of two complex images,
* @(#) expressed as a complex image where the modulus of each pixel is * @(#) expressed as a complex image where the modulus of each pixel is
* @(#) one. * @(#) one.
* @(#) * @(#)
* @(#) I.E. find (a.b*)/|a.b*| where * @(#) I.E. find (a.b*)/|a.b*| where
* @(#) . represents complex multiplication * @(#) . represents complex multiplication
* @(#) * represents the complex conjugate * @(#) * represents the complex conjugate
* @(#) || represents the complex modulus * @(#) || represents the complex modulus
* @(#) * @(#)
@ -16,12 +16,17 @@
* *
* Author: Tom Vajzovic * Author: Tom Vajzovic
* Written on: 2008-01-09 * Written on: 2008-01-09
*
* 2008-02-04 tcv:
* - exp( i.th ) == cos(th)+i.sin(th) NOT sin(th)+i.cos(th)
* - add quadratic version (ifdef'd out ATM - still using trigonometric one)
*
*/ */
/* /*
This file is part of VIPS. This file is part of VIPS.
VIPS is free software; you can redistribute it and/or modify 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 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 the Free Software Foundation; either version 2 of the License, or
@ -58,8 +63,69 @@
#include <dmalloc.h> #include <dmalloc.h>
#endif /*WITH_DMALLOC*/ #endif /*WITH_DMALLOC*/
static void double_complex_phase( void *in1, void *in2, void *out, int n, void *im, void *unrequired );
static void float_complex_phase( void *in1, void *in2, void *out, int n, void *im, void *unrequired ); /* There doesn't seem to be much difference in speed between these two methods (on an Athlon64),
* so I use the modulus argument version, since atan2() is in c89 but hypot() is c99.
*
* If you think that it might be faster on your platform, uncomment the following:
*/
#define USE_MODARG_DIV
#ifdef USE_MODARG_DIV
#define COMPLEX_PHASE_FN( TYPE, ABS ) \
static void \
complex_phase_ ## TYPE ( void *in1, void *in2, void *out, int n, void *im, void *unrequired ){ \
\
TYPE *X= (TYPE*) in1; \
TYPE *Y= (TYPE*) in2; \
TYPE *Z= (TYPE*) out; \
TYPE *Z_stop= Z + 2 * n * ((IMAGE*)im)-> Bands; \
\
for( ; Z < Z_stop; X+= 2, Y+= 2 ){ \
double arg= atan2( X[1], X[0] ) - atan2( Y[1], Y[0] ); \
*Z++= cos( arg ); \
*Z++= sin( arg ); \
} \
}
#else /* USE_MODARG_DIV */
#define COMPLEX_PHASE_FN( TYPE, ABS ) \
static void \
complex_phase_ ## TYPE ( void *in1, void *in2, void *out, int n, void *im, void *unrequired ){ \
\
TYPE *X= (TYPE*) in1; \
TYPE *Y= (TYPE*) in2; \
TYPE *Z= (TYPE*) out; \
TYPE *Z_stop= Z + 2 * n * ((IMAGE*)im)-> Bands; \
\
for( ; Z < Z_stop; X+= 2, Y+= 2 ) \
\
if( ABS( Y[0] ) > ABS( Y[1] )){ \
double a= Y[1] / Y[0]; \
double b= Y[0] + Y[1] * a; \
double re= ( X[0] + X[1] * a ) / b; \
double im= ( X[1] - X[0] * a ) / b; \
double mod= im__hypot( re, im ); \
*Z++= re / mod; \
*Z++= im / mod; \
} \
else { \
double a= Y[0] / Y[1]; \
double b= Y[1] + Y[0] * a; \
double re= ( X[0] * a + X[1] ) / b; \
double im= ( X[1] * a - X[0] ) / b; \
double mod= im__hypot( re, im ); \
*Z++= re / mod; \
*Z++= im / mod; \
} \
}
#endif /* USE_MODARG_DIV */
COMPLEX_PHASE_FN( float, fabsf )
COMPLEX_PHASE_FN( double, fabs )
int im_cross_phase( IMAGE *a, IMAGE *b, IMAGE *out ){ int im_cross_phase( IMAGE *a, IMAGE *b, IMAGE *out ){
#define FUNCTION_NAME "im_phase" #define FUNCTION_NAME "im_phase"
@ -78,61 +144,15 @@ int im_cross_phase( IMAGE *a, IMAGE *b, IMAGE *out ){
if( a-> Coding || b-> Coding ){ if( a-> Coding || b-> Coding ){
im_error( FUNCTION_NAME, "not uncoded" ); im_error( FUNCTION_NAME, "not uncoded" );
return -1; return -1;
} }
if( a-> BandFmt != b-> BandFmt ){ if( a-> BandFmt != b-> BandFmt ){
im_error( FUNCTION_NAME, "formats differ" ); im_error( FUNCTION_NAME, "formats differ" );
return -1; return -1;
} }
if( IM_BANDFMT_COMPLEX != a-> BandFmt && IM_BANDFMT_DPCOMPLEX != a-> BandFmt ){ if( IM_BANDFMT_COMPLEX != a-> BandFmt && IM_BANDFMT_DPCOMPLEX != a-> BandFmt ){
im_error( FUNCTION_NAME, "not complex format" ); im_error( FUNCTION_NAME, "not complex format" );
return -1;
}
if( im_cp_descv( out, a, b, NULL )
|| im_wraptwo( a, b, out,
IM_BANDFMT_COMPLEX == a-> BandFmt ? float_complex_phase : double_complex_phase, a, NULL ))
return -1; return -1;
return 0;
}
static void double_complex_phase( void *in1, void *in2, void *out, int n, void *im, void *unrequired ){
double *a= (double*) in1;
double *b= (double*) in2;
double *o= (double*) out;
double *o_end= o + 2 * n * ((IMAGE*)im)-> Bands;
for( ; o < o_end; a+= 2, b+= 2 ){
double arg= atan2( a[1], a[0] ) - atan2( b[1], b[0] );
*o++= sin( arg );
*o++= cos( arg );
#if 0
/* FIXME very prone to overflow */
double re= a[0] * b[0] + a[1] * b[1];
double im= a[1] * b[0] - a[0] * b[1];
double mod= hypot( re, im );
*o++= re / mod;
*o++= im / mod;
#endif
}
}
static void float_complex_phase( void *in1, void *in2, void *out, int n, void *im, void *unrequired ){
float *a= (float*) in1;
float *b= (float*) in2;
float *o= (float*) out;
float *o_end= o + 2 * n * ((IMAGE*)im)-> Bands;
for( ; o < o_end; a+= 2, b+= 2 ){
double arg= atan2( a[1], a[0] ) - atan2( b[1], b[0] );
*o++= sin( arg );
*o++= cos( arg );
#if 0
/* FIXME very prone to overflow */
double re= (double)a[0] * (double)b[0] + (double)a[1] * (double)b[1];
double im= (double)a[1] * (double)b[0] - (double)a[0] * (double)b[1];
double mod= hypot( re, im );
*o++= re / mod;
*o++= im / mod;
#endif
} }
return im_cp_descv( out, a, b, NULL ) || im_wraptwo( a, b, out,
IM_BANDFMT_COMPLEX == a-> BandFmt ? complex_phase_float : complex_phase_double, a, NULL );
} }