box tutorial topographic-map

About BCI and box tutorial/demo scenarios bundled with OpenViBE.
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Bob
Posts: 2
Joined: Tue Jul 10, 2012 2:10 pm

box tutorial topographic-map

Post by Bob »

Hello openvibe community,

I have a question to the toppgraphic-map.xml file.
The algorithm displays the EEG-Signals of the bci-motor-imagery.ov file. I can understand that you can calculate the biopotential between two of the ten+1 electrodes(marked area). But how is it possible to calculate the potential outside of the red area? I mean, there is no recorded data for it.

best regards
Bob
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lbonnet
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Joined: Wed Oct 07, 2009 12:11 pm

Re: box tutorial topographic-map

Post by lbonnet »

Hi bob,

The topographic maps use interpolation to compute a value for each area of the map.
Different interpolation methods exist, here we use Spline interpolation.

Laurent
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Bob
Posts: 2
Joined: Tue Jul 10, 2012 2:10 pm

Re: box tutorial topographic-map

Post by Bob »

Thank you, Laurent.
But do you mean extrapolation?

yrenard
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Re: box tutorial topographic-map

Post by yrenard »

Dear Bob,

This is indeed extrapolation and should be considered with care, but I believe you already know that.

Hoep this helps,
Yann

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