OpenViBE forum

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

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

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

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.

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