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mri_stat_seq.c File Reference
#include "mrilib.h"Go to the source code of this file.
Functions | |
| MRI_IMAGE ** | mri_stat_seq (MRI_IMAGE *imin) |
Function Documentation
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Definition at line 18 of file mri_stat_seq.c. References EXIT, MRI_IMAGE::kind, malloc, MRI_COPY_AUX, mri_data_pointer(), mri_free(), MRI_IS_2D, mri_new(), mri_to_float(), MRI_IMAGE::nx, MRI_IMAGE::ny, and retval(). Referenced by main(), and mri_align_crao().
00019 {
00020
00021 /* static variables (exist between calls) */
00022
00023 static MRI_IMAGE * imsum , * imsumq ;
00024 static int nim = 0 , npix , nx , ny ;
00025 static double * dbsum , * dbsumq ;
00026
00027 /* local variables */
00028
00029 register int ii ;
00030 MRI_IMAGE * imfl , * imsd , ** retval ;
00031 float * flar , * sdar ;
00032 double scl , vscl , vvv ;
00033
00034 /*** case: set up new problem ***/
00035
00036 if( nim == 0 ){
00037
00038 if( imin == NULL ){
00039 fprintf(stderr,"mri_stat_seq: NULL argument for initial call!\n") ;
00040 EXIT(1) ;
00041 }
00042
00043 if( ! MRI_IS_2D(imin) ){
00044 fprintf(stderr,"\n*** mri_stat_seq: only works on 2D images!\n") ;
00045 EXIT(1) ;
00046 }
00047
00048 nx = imin->nx ;
00049 ny = imin->ny ;
00050 npix = nx * ny ;
00051
00052 imsum = mri_new( nx , ny , MRI_double ) ;
00053 imsumq = mri_new( nx , ny , MRI_double ) ;
00054 dbsum = mri_data_pointer( imsum ) ;
00055 dbsumq = mri_data_pointer( imsumq ) ;
00056
00057 MRI_COPY_AUX(imsum,imin) ;
00058
00059 for( ii=0 ; ii < npix ; ii++ ) dbsum[ii] = dbsumq[ii] = 0.0 ;
00060
00061 }
00062
00063 /*** case: add new image into problem ***/
00064
00065 if( imin != NULL ){
00066
00067 if( imin->nx != nx || imin->ny != ny ){
00068 fprintf(stderr,"mri_stat_seq: input image size mismatch!\n") ;
00069 EXIT(1) ;
00070 }
00071
00072 if( ! MRI_IS_2D(imin) ){
00073 fprintf(stderr,"\n*** mri_stat_seq: only works on 2D images!\n") ;
00074 EXIT(1) ;
00075 }
00076
00077 if( imin->kind == MRI_float ){
00078 imfl = imin ;
00079 } else {
00080 imfl = mri_to_float( imin ) ;
00081 }
00082 flar = mri_data_pointer( imfl ) ;
00083
00084 for( ii=0 ; ii < npix ; ii++ ){
00085 dbsum[ii] += flar[ii] ;
00086 dbsumq[ii] += flar[ii] * flar[ii] ;
00087 }
00088
00089 if( imin != imfl ) mri_free( imfl ) ;
00090 nim++ ;
00091 return NULL ;
00092 }
00093
00094 /*** case: make report on results, and reset static data ***/
00095
00096 if( nim < 1 ){
00097 fprintf(stderr,"mri_stat_seq: # images input=%d; too small!\n",nim) ;
00098 EXIT(1) ;
00099 }
00100
00101 imfl = mri_new( nx , ny , MRI_float ) ;
00102 imsd = mri_new( nx , ny , MRI_float ) ;
00103 flar = mri_data_pointer( imfl ) ;
00104 sdar = mri_data_pointer( imsd ) ;
00105
00106 MRI_COPY_AUX(imfl,imsum) ;
00107
00108 scl = 1.0 / nim ;
00109 vscl = (nim==1) ? 1.0 : sqrt( ((double)(nim))/(nim-1.0) ) ;
00110
00111 for( ii=0 ; ii < npix ; ii++ ){
00112 flar[ii] = scl * dbsum[ii] ;
00113 vvv = scl * dbsumq[ii] - flar[ii] * flar[ii] ;
00114 sdar[ii] = (vvv > 0.0) ? (sqrt(vvv)*vscl) : 0.0 ;
00115 }
00116
00117 mri_free( imsum ) ; mri_free( imsumq ) ;
00118 nim = 0 ;
00119
00120 retval = (MRI_IMAGE **) malloc( 2 * sizeof(MRI_IMAGE *) ) ;
00121 if( retval == NULL ){
00122 fprintf(stderr,"mri_stat_seq: malloc error for retval!\n") ;
00123 EXIT(1) ;
00124 }
00125
00126 retval[0] = imfl ;
00127 retval[1] = imsd ;
00128
00129 return retval ;
00130 }
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