Extracting brandwave spectra (alpha, etc...) -what method?

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WHY5Research
Posts: 2
Joined: Fri Apr 13, 2012 8:53 am

Extracting brandwave spectra (alpha, etc...) -what method?

Post by WHY5Research »

Hi,

I'm using OpenVibe to process the data from Emotiv EPOC headset.
For my research I need to extract the amplitudes of Alpha, Beta, etc... brainwaves with pre-defined frequency ranges.

I see 2 possible methods:
1. Apply FFT (with 0.16HZ pre-filtering + windowing) and extract the right spectra.
2. Apply a band-pass filter (e.g 16-24HZ for Beta waves) on the raw data.

Which method would be the best?

Thank you in advance

Alexei

fabien.lotte
Posts: 112
Joined: Sun Mar 14, 2010 12:58 pm

Re: Extracting brandwave spectra (alpha, etc...) -what metho

Post by fabien.lotte »

Both approaches would give rather similar performances, but the second-one may give slightly better results. I would suggest you have a look at the following papers who compared different approaches to extract band-power features for BCI:

Herman, Pawel, Prasad, Girijesh, McGinnity, Martin and Coyle, Damien (2008) Comparative analysis of spectral approaches to feature extraction for EEG-based motor imagery classification. IEEE transactions on neural systems and rehabilitation engineering: a publication of the IEEE Engineering in Medicine and Biology Society, 16 (4). pp. 317-26.
http://eprints.ulster.ac.uk/4141/

N. Brodu, F. Lotte, A. Lécuyer, "Comparative Study of Band-Power Extraction Techniques for Motor Imagery Classification", 2011 IEEE Symposium on Computational Intelligence, Cognitive Algorithms, Mind, and Brain (SSCI'2011 CCMB), pp. 1-6, 2011
http://hal.inria.fr/docs/00/60/91/61/PD ... _final.pdf

WHY5Research
Posts: 2
Joined: Fri Apr 13, 2012 8:53 am

Re: Extracting brandwave spectra (alpha, etc...) -what metho

Post by WHY5Research »

Thank you for your input!

I have one more qustion: I need to visualize the brand wave amplitudes in real time.
The visualization tools included into OpenVibe are quite limited.

Is there a way to export brain spectra to external graphical packages? If yes, how?

Thank you


ALexei

fabien.lotte
Posts: 112
Joined: Sun Mar 14, 2010 12:58 pm

Re: Extracting brandwave spectra (alpha, etc...) -what metho

Post by fabien.lotte »

The most common way to send data from OpenViBE to an external application would be to use VRPN (http://openvibe.inria.fr/vrpn-tutorial- ... plication/).
But this is a generic method, there is no dedicated connection to another graphical application.

ddvlamin
Posts: 160
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Location: Ghent University
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Re: Extracting brandwave spectra (alpha, etc...) -what metho

Post by ddvlamin »

You could also try to use the matlab box and use matlab to plot the things you want to plot. Or if you do not have matlab, maybe there is a similar python box? Although I can not seem to find a python box, I definitely heard that someone developed that? Does anyone know the person who did?

EDIT: Ok stupid me, I found the python box after an update, it should be in the python directory inside the openvibe-plugins directory

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