[FieldTrip] coordinate transform

[jan-mathijs schoffelen]

Hi Qi,

Could you be a bit more specific? In what coordinate system are the fiducials defined? MRI-voxel space? MEG-dewar space? Something else?
There is a headcoordinates function in fieldtrip/private, which is computing a 4x4 affine transformation matrix for you (from which the rotation and translation can be determined). The high level fieldtrip functions you may want to look into are ft_electroderealign, or ft_volumerealign. 

Best,

Jan-Mathijs

On Feb 8, 2012, at 5:14 PM, qi li wrote:

> Hi,
> 
> I want to do a coordinate transformation of the sensor positions by
> knowing the fiducial point(na,lpa,rpa). Is there any function can do
> this? More specifically I want to know the 3 translational and 3
> rotational degree changes between the original coordinate and the
> changed one.
> 
> Thanks a lot!
> 
> Qi
> _______________________________________________
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> fieldtrip at donders.ru.nl
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Jan-Mathijs Schoffelen, MD PhD 

Donders Institute for Brain, Cognition and Behaviour, 
Centre for Cognitive Neuroimaging,
Radboud University Nijmegen, The Netherlands

Max Planck Institute for Psycholinguistics,
Nijmegen, The Netherlands

J.Schoffelen at donders.ru.nl
Telephone: +31-24-3614793

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