[FieldTrip] Polhemus Patriot

[Julian Keil]

Dear FieldTrip-Users,

I have a not really FieldTrip-related question, but maybe one of you can help me anyways.
In our lab, we have a Polhemus Patriot 3D tracking system to acquire electrode positions.
Unfortunately, the recordings are severely distorted in the Z-axis (up-down).
After contacting the Polhemus Support, I got the information, that this is due to metal in the surroundings of the source which distorts the magnetic field.
I tried to get as far away from any metal as possible in our lab (~1.5 m to the walls and floor) but to no avail.

Now to my question: Has anyone any experience dealing with this? I'm quite puzzled by this as I know plenty of labs use Polhemus trackers, and I'm not sure if our lab is especially metal prone or if I'm missing something.

Thanks a lot for any help.

Julian

********************
Dr. Julian Keil

AG Multisensorische Integration
Psychiatrische Universitätsklinik
der Charité im St. Hedwig-Krankenhaus
Große Hamburger Straße 5-11, Raum E 307
10115 Berlin

Telefon: +49-30-2311-1879
Fax:        +49-30-2311-2209 
http://psy-ccm.charite.de/forschung/bildgebung/ag_multisensorische_integration

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