congratulations for getting this to work ! 78% is not an excellent classifier performance in case of the P300 speller but with 12 repetitions, it indeed leads to correct detection. Did you try to play with the number of repetitions as well ?
What happens if I run/play multiple times in the "p300-speller-2-train-xDAWN.xml" (or "p300-speller-3-train-classifier") in the training phase? Does the new training gets accumulated and stored in the .ov file OR does it overwrite the previous training in the .ov file?
The training is not iterative. The data is recorded in separate files so you can train on any of them but not all of them. If you want more data to train on, just spell more letters in one session.
I would like to change the dimension of the P300 matrix. Also I would like to change the graphics? For example, 3 x 3 matrix with photos. Is there an easy way to do this?
Did you look at the Magic Card scenarios ?
If I had to remove some of the EEG sensors of the Emotiv EPOC headset to minimize the total number of sensors, which EEG sensors should I keep for P300-speller in the Emotiv?
Channel names in Emotiv headset based on the International 10-20 locations are: AF3, F7, F3, FC5, T7, P7, O1, O2, P8, T8, FC6, F4, F8, AF4
I recommand you read this article http://hal.archives-ouvertes.fr/hal-00517388
Any plans for OpenViBE technical conference? Or any recommendation for upcoming good BCI conferences?
There will be some OpenViBE workshop by the end of 2011 but not before this. If interested in BCI events, you should have a look at Fabien Lotte's dedicated page
Hope this helps,