HI,
I created a scalp surface mesh with mkheadsurf. I need to mark or select some scalp surface points and obtain their MRI coordinates. That is, if my MRI is 256-cubed I need the (ix,iy,iz) MRI voxel coordinates closest to the scalp mesh point I mark, where these run from 1 to 256 (or 0-255 if you must). The tksurfer display shows several types of floating point coordinates, but they assume an origin in the center of the head somewhere. If I knew the MRI coordinates of this origin I could calculate the original MRI.
Thanks, -Jeff
Hi Jeff The coordinate conversions are documented on our wiki. Or you could do the marking in tkmedit or freeview which will show you voxel and surface RAS coords. There might also be an option to view them in tksurfer too, I can't remember (view->information or something like that) Cheers Bruce
On Jan 2, 2013, at 7:43 PM, Jeff Eriksen eriksenj@ohsu.edu wrote:
HI,
I created a scalp surface mesh with mkheadsurf. I need to mark or select some scalp surface points and obtain their MRI coordinates. That is, if my MRI is 256-cubed I need the (ix,iy,iz) MRI voxel coordinates closest to the scalp mesh point I mark, where these run from 1 to 256 (or 0-255 if you must). The tksurfer display shows several types of floating point coordinates, but they assume an origin in the center of the head somewhere. If I knew the MRI coordinates of this origin I could calculate the original MRI.
Thanks, -Jeff
Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer
freesurfer@nmr.mgh.harvard.edu
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Bruce Fischl -
Jeff Eriksen