Search found 109 matches

by jawilson
13 Sep 2010, 10:59
Forum: Configuration
Topic: P300 Speller - Worng Letter, correct line
Replies: 18
Views: 6437

There is a lot of information on the wiki, at http://www.bci2000.org/wiki/index.php/User_Reference:P300Classifier . Basically, it uses a step-wise linear discriminate analysis to try to find the time points that are significantly associated with the correct stimulus, and uses those for the classifie...
by jawilson
10 Sep 2010, 10:07
Forum: Configuration
Topic: P300 Speller - Worng Letter, correct line
Replies: 18
Views: 6437

Timur,
Sorry, I meant the P300 Classifier, not the P300 GUI (they do similar things, but the GUI requires matlab, and I confused them!).
Let us know if this works better for you!
Adam
by jawilson
08 Sep 2010, 09:29
Forum: Configuration
Topic: P300 Speller - Worng Letter, correct line
Replies: 18
Views: 6437

Timur, I can almost certainly promise you that the P300 speller uses both the row and column, since this is a bug that probably would have been detected in the last decade and dozens of papers :D . I would definitely make using the P300 GUI a priority; it works VERY well, and will likely eliminate a...
by jawilson
30 Aug 2010, 10:28
Forum: Configuration
Topic: Offline Analysis for Speller Calibration Session
Replies: 4
Views: 2741

You might want to try using the P300 GUI tool, found at http://www.bci2000.org/wiki/index.php/User_Tutorial:P300_GUI_for_Offline_Analysis_Tutorial . This does not generate plots, but it will generate a classification matrix using a linear stepwise regression, and tends to work better than the Matlab...
by jawilson
30 Aug 2010, 10:25
Forum: Software Development
Topic: Can BCI2000 read raw eeg from emotiv epoc headset ($299)?
Replies: 3
Views: 2796

Yes, Emotiv research headsets are supported as a contribution.
by jawilson
30 Aug 2010, 10:24
Forum: Configuration
Topic: P300 Speller - Worng Letter, correct line
Replies: 18
Views: 6437

Timur, The short answer is that you should probably be using the P300 GUI to automatically generate the correct classification matrix. See http://www.bci2000.org/wiki/index.php/User_Tutorial:P300_GUI_for_Offline_Analysis_Tutorial for information on using this, since it works much better. If you are ...
by jawilson
22 Jul 2010, 08:27
Forum: BCI Systems - Signal Processing
Topic: Offline analysis.
Replies: 12
Views: 4868

Ok, a few things: 1. I would use labels for your ChannelNames, to make sure that the channels are in the right order, e.g., ChannelNames= 12 F3 F4 P3 P4 C3 Cz C4... (I'm not sure what order your channels are in, so adjust this accordingly). 2. Do you have a low impedance EEG headstage? If so, then T...
by jawilson
21 Jul 2010, 15:33
Forum: BCI Systems - Signal Processing
Topic: Offline analysis.
Replies: 12
Views: 4868

Can you post the contents of the parameter file you are using? I would like to see your configuration before commenting.
by jawilson
16 Jul 2010, 08:11
Forum: Data Analysis
Topic: MEX files
Replies: 3
Views: 3232

Ok, I see the problem. You need to pass the Frequency parameter, which is optional. If you do not pass it, then it defaults to 1, and all of your values would then need to be scaled accordingly, e.g., 0.0 <= BinWidth < 0.5, and so on. This parameter lets the program know what the sample rate is. So,...
by jawilson
16 Jul 2010, 08:07
Forum: BCI Systems - Signal Processing
Topic: cursor task
Replies: 6
Views: 2842

The power is updated every sample block, using a signal of length WindowLength; in other words, it is a sliding window. For example, if your block size is 50 ms and your window length is 500 ms, the power will be calculated on a 500 ms window every 50 ms. You could change the block size to 100 ms, a...
by jawilson
15 Jul 2010, 10:10
Forum: BCI Systems - Signal Processing
Topic: cursor task
Replies: 6
Views: 2842

The EvaluationsPerBin and ModelOrder do not depend on each other in any way. The ModelOrder is the model order of the auto-regressive model, which is used to estimate the power. This could be 10, or it could be 120; a higher model order will provide more "bumps" in the frequency domain, but if it is...
by jawilson
14 Jul 2010, 10:30
Forum: BCI Systems - Signal Processing
Topic: cursor task
Replies: 6
Views: 2842

The linear classifier will use the bin from 10.5-13.5 Hz, which contains the mean of all of the amplitudes in this range. The number of values in a bin depends on the EvaluationsPerBin parameter. For example, if EvaluationsPerBin is 15, then the mean 15 evenly-spaced values will be calculated from 1...
by jawilson
14 Jul 2010, 10:25
Forum: Data Analysis
Topic: MEX files
Replies: 3
Views: 3232

It is hard to tell what is happening, but it appears the signal might not be in the matlab "double" format. You can try this:

Code: Select all

signal = double(signal);
[spectrum, frequencies] = mem(signal, parms); 
or this:

Code: Select all

[spectrum, frequencies] = mem(double(signal), parms); 
and it might work.
Adam
by jawilson
13 Jul 2010, 09:13
Forum: Software Development
Topic: about Mario Mu Rhythm Off-line Analysis
Replies: 2
Views: 1715

Hello, Unfortunately, there is currently no such tool for the sensorimotor rhythm tasks, although something may be in the works. Fortunately, with the motor tasks, you have a good a priori idea of which electrodes (C3, Cz, C4, plus T7/T8 for facial, I assume?) and frequency ranges (mu, beta) will be...
by jawilson
13 Jul 2010, 09:09
Forum: Software Development
Topic: BCI2000 for 64Bit CPU
Replies: 1
Views: 1477

Since none of my German-speaking colleagues have responded, I'll take a stab at this: First, currently BCI2000 is not supported as a 64-bit application. However, you CAN run it as a 32-bit application on 64-bit Windows, like I do on my computer. However, many of the drivers are not supported yet, mo...