[FieldTrip] Polhemus Patriot

[Sarang S. Dalal]

Dear Julian,

At UCSF, we were unable to use a Polhemus (an older model, not sure which) in the shielded room of the MEG, so we performed the digitization just outside the room before moving the subject inside. Perhaps if you have a nicely shielded EEG booth you have the same problem...

Sarang


On Jun 3, 2013, at 9:08 AM, fieldtrip-request at science.ru.nl wrote:
> Date: Mon, 3 Jun 2013 17:14:08 +0200
> From: Julian Keil <julian.keil at gmail.com>
> To: FieldTrip discussion list <fieldtrip at science.ru.nl>
> Subject: [FieldTrip] Polhemus Patriot
> Message-ID: <67D8C434-4D28-40C3-94A6-A95C86BD6B78 at gmail.com>
> Content-Type: text/plain; charset="iso-8859-1"
> 
> 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
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