Estimate fiducials for a subject.
The FreeSurfer subject name.
The path to the directory containing the FreeSurfer subjects
None, defaults to the
List of estimated fiducials (each point in a dict), in the order LPA, nasion, RPA.
This takes the
fsaverage-fiducials.fif file included with MNE—which
contain the LPA, nasion, and RPA for the
transforms them to the given FreeSurfer subject’s MRI space.
The MRI of
fsaverage is already in MNI Talairach space, so applying
the inverse of the given subject’s MNI Talairach affine transformation
$SUBJECTS_DIR/$SUBJECT/mri/transforms/talairach.xfm) is used
to estimate the subject’s fiducial locations.
For more details about the coordinate systems and transformations involved, see https://surfer.nmr.mgh.harvard.edu/fswiki/CoordinateSystems and Source alignment and coordinate frames.