Hi Colleen
After correction the Euler number should be exactly 2. If it is not, it means
the surface is not topologically equivalent to a sphere. Every defect (hole or
handle) will decrease it by 2, so an Euler number of -18 (like your lh below)
is:
# of holes = (2-euler_number)/2 = (2--18)/2 = 10
Make sense?
Cheers
Bruce
-----Original Message-----
From: freesurfer-boun...@nmr.mgh.harvard.edu
<freesurfer-boun...@nmr.mgh.harvard.edu> On Behalf Of C.P.E. Rollins
Sent: Thursday, September 3, 2020 12:17 PM
To: Freesurfer <freesurfer@nmr.mgh.harvard.edu>
Subject: [Freesurfer] how to calculate Euler number
External Email - Use Caution
Dear Freesurfer Developers,
It is not clear to me how to calculate the Euler number. Using mri_segstats
reports something like:
Computing euler number
orig.nofix lheno = -18, rheno = -20
orig.nofix lhholes = 10, rhholes = 11
However, I had understood from previous comments that the Euler number should
be around 2. I'm wondering which of the above numbers I could report.
Thanks,
Colleen
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