static MATRIX *
align_pca(MRI *mri_in, MRI *mri_ref) {
int row, col, i ;
float dot ;
MATRIX *m_ref_evectors = NULL, *m_in_evectors = NULL ;
float in_evalues[3], ref_evalues[3] ;
double ref_means[3], in_means[3] ;
#if 0
MRI *mri_in_windowed, *mri_ref_windowed ;
mri_in_windowed = MRIwindow(mri_in, NULL, WINDOW_HANNING,127,127,127,100.0f);
mri_ref_windowed = MRIwindow(mri_ref,NULL,WINDOW_HANNING,127,127,127,100.0f);
if (Gdiag & DIAG_WRITE) {
MRIwriteImageViews(mri_in_windowed, "in_windowed", 400) ;
MRIwriteImageViews(mri_ref_windowed, "ref_windowed", 400) ;
}
#endif
if (!m_ref_evectors)
m_ref_evectors = MatrixAlloc(3,3,MATRIX_REAL) ;
if (!m_in_evectors)
m_in_evectors = MatrixAlloc(3,3,MATRIX_REAL) ;
MRIprincipleComponents(mri_ref, m_ref_evectors, ref_evalues,
ref_means, thresh_low);
MRIprincipleComponents(mri_in,m_in_evectors,in_evalues,in_means,thresh_low);
/* check to make sure eigenvectors aren't reversed */
for (col = 1 ; col <= 3 ; col++) {
#if 0
float theta ;
#endif
for (dot = 0.0f, row = 1 ; row <= 3 ; row++)
dot += m_in_evectors->rptr[row][col] * m_ref_evectors->rptr[row][col] ;
if (dot < 0.0f) {
printf("WARNING: mirror image detected in eigenvector #%d\n",
col) ;
dot *= -1.0f ;
for (row = 1 ; row <= 3 ; row++)
m_in_evectors->rptr[row][col] *= -1.0f ;
}
#if 0
theta = acos(dot) ;
printf("angle[%d] = %2.1f\n", col, DEGREES(theta)) ;
#endif
}
printf("ref_evectors = \n") ;
for (i = 1 ; i <= 3 ; i++)
printf("\t\t%2.2f %2.2f %2.2f\n",
m_ref_evectors->rptr[i][1],
m_ref_evectors->rptr[i][2],
m_ref_evectors->rptr[i][3]) ;
printf("\nin_evectors = \n") ;
for (i = 1 ; i <= 3 ; i++)
printf("\t\t%2.2f %2.2f %2.2f\n",
m_in_evectors->rptr[i][1],
m_in_evectors->rptr[i][2],
m_in_evectors->rptr[i][3]) ;
return(pca_matrix(m_in_evectors, in_means,m_ref_evectors, ref_means)) ;
}
static MATRIX *
compute_pca(MRI *mri_in, MRI *mri_ref) {
int row, col, i ;
float dot ;
MATRIX *m_ref_evectors = NULL, *m_in_evectors = NULL ;
float in_evalues[3], ref_evalues[3] ;
double ref_means[3], in_means[3] ;
if (!m_ref_evectors)
m_ref_evectors = MatrixAlloc(3,3,MATRIX_REAL) ;
if (!m_in_evectors)
m_in_evectors = MatrixAlloc(3,3,MATRIX_REAL) ;
if (binarize) {
MRIbinaryPrincipleComponents(mri_ref, m_ref_evectors, ref_evalues,
ref_means, thresh_low);
MRIbinaryPrincipleComponents(mri_in,m_in_evectors,in_evalues,in_means,
thresh_low);
} else {
MRIprincipleComponents(mri_ref, m_ref_evectors, ref_evalues, ref_means,
thresh_low);
MRIprincipleComponents(mri_in,m_in_evectors,in_evalues,in_means,
thresh_low);
}
order_eigenvectors(m_in_evectors, m_in_evectors) ;
order_eigenvectors(m_ref_evectors, m_ref_evectors) ;
/* check to make sure eigenvectors aren't reversed */
for (col = 1 ; col <= 3 ; col++) {
#if 0
float theta ;
#endif
for (dot = 0.0f, row = 1 ; row <= 3 ; row++)
dot += m_in_evectors->rptr[row][col] * m_ref_evectors->rptr[row][col] ;
if (dot < 0.0f) {
fprintf(stderr, "WARNING: mirror image detected in eigenvector #%d\n",
col) ;
dot *= -1.0f ;
for (row = 1 ; row <= 3 ; row++)
m_in_evectors->rptr[row][col] *= -1.0f ;
}
#if 0
theta = acos(dot) ;
fprintf(stderr, "angle[%d] = %2.1f\n", col, DEGREES(theta)) ;
#endif
}
fprintf(stderr, "ref_evectors = \n") ;
for (i = 1 ; i <= 3 ; i++)
fprintf(stderr, "\t\t%2.2f %2.2f %2.2f\n",
m_ref_evectors->rptr[i][1],
m_ref_evectors->rptr[i][2],
m_ref_evectors->rptr[i][3]) ;
fprintf(stderr, "\nin_evectors = \n") ;
for (i = 1 ; i <= 3 ; i++)
fprintf(stderr, "\t\t%2.2f %2.2f %2.2f\n",
m_in_evectors->rptr[i][1],
m_in_evectors->rptr[i][2],
m_in_evectors->rptr[i][3]) ;
return(pca_matrix(m_in_evectors, in_means,m_ref_evectors, ref_means)) ;
}
