[FieldTrip] Fixing bad segmentation for EEG forward modelling

[Jason Leung]

Hello Fieldtrip community,

I'm following the steps from the "Forward modeling for EEG source
reconstruction" tutorial, and am having trouble creating the headmodel from
the meshes of the segmented MRI. Note that I am using my own MRI image and
I am using the OpenMEEG method for preparing the head model.

When I call ft_prepare_headmodel, I get an error message saying that my
meshes are intersecting. I tried plotting the meshes and noticed that there
were spikes in one of the meshes, so I changed the number of vertices
around to get rid of them. However, even after doing that, I still get the
same error messages. This leads me to think the issue is with the
segmentation. Following the "Bonus: troubleshooting the meshes" section in
the tutorial, I tried plotting the segmented mri, and it does look like
some areas of the skin are too thin. However, I am not sure how to proceed
at this point. What parameters can I adjust in the ft_volumesegment to fix
it? Is it possible to manually fix the segmentation? Any input will be
greatly appreciated!

Please find the output of the ft_volumesegment and ft_prepare_headmodel
functions, the plots, and the code here (https://jpst.it/2mOcE).

Thank you very much in advance for your help!

Jason
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