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box tutorial topographic-map

Posted: Tue Jul 10, 2012 2:20 pm
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

Re: box tutorial topographic-map

Posted: Wed Jul 11, 2012 7:02 am
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

Re: box tutorial topographic-map

Posted: Wed Jul 11, 2012 11:00 am
by Bob
Thank you, Laurent.
But do you mean extrapolation?

Re: box tutorial topographic-map

Posted: Thu Sep 20, 2012 7:24 pm
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