[FieldTrip] ft_electroderealign

[tibor.auer at gmail.com]

Nevermind. I managed to sort it out based on NFT
<https://sccn.ucsd.edu/nft/> 's Coregistration.

 

Kind regards,

Tibor 

 

Auer, Tibor M.D. Ph.D.

Research Fellow

School of Psychology, Faculty of Health and Medical Sciences

University of Surrey, Guildford GU2 7XH

T.Auer at surrey.ac.uk <mailto:T.Auer at surrey.ac.uk> 

@TiborAuer
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From: tibor.auer at gmail.com <tibor.auer at gmail.com> 
Sent: Saturday, October 3, 2020 1:11 AM
To: 'FieldTrip discussion list' <fieldtrip at science.ru.nl>
Subject: ft_electroderealign

 

Dear colleagues,

 

I am experiencing an issue with the ft_electroderealign.

 

I would like to fit the electrode to the scalp because the initial alignment
(see fieldtrip_start.png) is not optimal.

(The attached diag.tiff is a MAT-file. You have to rename it to diag.mat
before loading if you want to experiment with the data.)

 

I have created a mesh of the scalp (mesh) and identified erroneous positions
close to the edge of the FOV (meshedge).

 

I thought the following code should do the re-alignment:

cfg = [];

cfg.method = 'headshape';

cfg.warp = 'traditional';

cfg.headshape = mesh.pos(~meshedge,:);

elec  = ft_electroderealign(cfg, elec);

However, it barely moves the electrodes (see fieldtrip_traditional.png). I
have also tried nonlinear warping, but it did not help.

 

I have also tried manually, and by simply changing the scale of two axes (y
and z) by 1.25 and shifting the electrodes backwards by 12.5mm worked (see
fieldtrip_interactive.png).

 

I have ca. 200 participants, and I would prefer to have an automatic
solution like the snippet above.

 

Kind regards,

Tibor 

 

Auer, Tibor M.D. Ph.D.

Research Fellow

School of Psychology, Faculty of Health and Medical Sciences

University of Surrey, Guildford GU2 7XH

T.Auer at surrey.ac.uk <mailto:T.Auer at surrey.ac.uk> 

@TiborAuer
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om%2FTiborAuer&data=02%7C01%7Ct.auer%40surrey.ac.uk%7Cdb32da458c424eedef2908
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