On Wed, Feb 20, 2008 at 10:46 PM, Doug Greve <[EMAIL PROTECTED]> wrote: > On Wed, 20 Feb 2008, Mishkin Derakhshan wrote: > > > Hi, > > > > 1. When using mris_convert lh.white lh.white.ascii, what co-oridnate > > system are the xyz co-ordinates reported in? ie. is it the RAS > > co-ordinates of the T1.mgz volume? > > These are "surface RAS" or "tkregister RAS". There is a power point > presentation on coord systems on the wiki.
So according to the overview on https://surfer.nmr.mgh.harvard.edu/fswiki/CoordinateSystems if I wanted to go from the SurfaceRAS (ie. what the lh.white.ascii is in) back to the coord system of my original volume, i would transform my object with the matrix M = inv(xform3)*inv(xform2)*inv(xform1) ? The diagram leads me to believe this is the same as M = inv(4)*inv(1) ? The text also says the SurfaceRasFromVoxel matrix is: [ 3x3 part (t1 - c_r)] [ same as (t2 - c_a)] [ xform0 (t3 - c_s)] [ 0 1 ] So the inverse of that would be what I'm looking for as well right? In that case, what is xform0? Just my directional cosines of the original image? Would t1,t2,t3 =0 then? thanks for the help, mishkin > > > > > 2. I am making the assumption that the lh.white and the lh.pial will > > always have the same number of indices and polygons. Can I also make > > the assumption that the order in which they are printed using > > mris_convert will be the same. ie. Will the vertex on line 54 of > > lh.white.ascii correspond to the same vertex on line 54 of > > lh.pial.ascii? > > Yes. > > doug > > > thanks, > > mishkin > > _______________________________________________ > > Freesurfer mailing list > > Freesurfer@nmr.mgh.harvard.edu > > https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer > > > > > > > > -- > Douglas N. Greve, Ph.D. > MGH-NMR Center > [EMAIL PROTECTED] > Phone Number: 617-724-2358 > Fax: 617-726-7422 > > In order to help us help you, please follow the steps in: > surfer.nmr.mgh.harvard.edu/fswiki/BugReporting > > _______________________________________________ Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer
