Search found 10 matches

by bertocasta
11 Jun 2015, 14:35
Forum: Data Analysis
Topic: Data in each step of a Visuall P300 Speller
Replies: 3
Views: 1504

Re: Data in each step of a Visuall P300 Speller

Hi again, Peter, I've tried to use all of these options. [1] Offline Analysis only allows me to plot the r-squared value or target/non-target stimulus for a given channel and time interval. [2] I've sucessfully loaded the XXXXXX.dat file. But at this point, no processing is done. I only have the raw...
by bertocasta
11 Jun 2015, 13:11
Forum: Data Analysis
Topic: Data in each step of a Visuall P300 Speller
Replies: 3
Views: 1504

Data in each step of a Visuall P300 Speller

Hi, I'm trying to perform an analysis of a P300 Visual Speller and I need to get some figures of the data. I've acces to raw data (files .dat created by the BCI2000 application). As long as I know, the processing steps are as follow: *Spatial Filter (CAR or others) *Dividing in epochs and averaging ...
by bertocasta
11 Jun 2015, 06:47
Forum: BCI Systems - Signal Processing
Topic: How P300 LinearClassifier works?
Replies: 13
Views: 3192

Re: How P300 LinearClassifier works?

Peter,

Thank you so much for your help. I appreciate it so much man. Thank you.

Regards
by bertocasta
10 Jun 2015, 17:24
Forum: BCI Systems - Signal Processing
Topic: How P300 LinearClassifier works?
Replies: 13
Views: 3192

Re: How P300 LinearClassifier works?

Peter,

I attach a image showing what I think that correlation do.
Image

That's right?

Regards, Alberto.
by bertocasta
10 Jun 2015, 14:16
Forum: BCI Systems - Signal Processing
Topic: How P300 LinearClassifier works?
Replies: 13
Views: 3192

Re: How P300 LinearClassifier works?

pbrunner, Let's see if I understood it. *You correlate those time points corresponding to a target stimulus with 1. *You correlate those time points corresponding to a non-target sitmulus with 0. So, when the r-squared of these correlations are maximum, those are the time points with the strongest r...
by bertocasta
10 Jun 2015, 13:35
Forum: BCI Systems - Signal Processing
Topic: How P300 LinearClassifier works?
Replies: 13
Views: 3192

Re: How P300 LinearClassifier works?

Peter,

I understand how it is calculated. What I don't know is why the relevant marks of time are those with largest r-squared values since the larger the r2, the more correlated are both stimulus (target and not target).

Regards, Alberto.
by bertocasta
10 Jun 2015, 06:39
Forum: BCI Systems - Signal Processing
Topic: How P300 LinearClassifier works?
Replies: 13
Views: 3192

Re: How P300 LinearClassifier works?

pbrunner, Ok, I think I gor it. The Classifier Matrix contains the weights for the element we are interested in, right? While performing a calibrating sesion, I am supposed to chose those values with larger r-squared calculated between attended and unattended stimulus, right? Those time marks will b...
by bertocasta
09 Jun 2015, 16:39
Forum: BCI Systems - Signal Processing
Topic: How P300 LinearClassifier works?
Replies: 13
Views: 3192

Re: How P300 LinearClassifier works?

pbrunner,

Thank you so much for your answer, it clarified a lot of my questions about it.

Next question, can you explain to me in more detail what's that you called multi-variate regresion?

Thank you.
by bertocasta
06 Jun 2015, 05:16
Forum: BCI Systems - Signal Processing
Topic: How P300 LinearClassifier works?
Replies: 13
Views: 3192

How P300 LinearClassifier works?

Hi everyone. I'm really new in this world, but I'm performing my Degree Project using BCI2000, so I have few questions about how modules work. I've found some information about how the P300SignalProcessing works, if I'm not wrong: It applies a spatial filter. It takes a matrix ChannelsxSamples and g...
by bertocasta
28 May 2015, 06:11
Forum: Configuration
Topic: P300 Speller doesn't start
Replies: 1
Views: 1306

P300 Speller doesn't start

Hello, I've been trying to do a P300 Speller with my Enobio system usign BCI2000. After set the config and start the Speller, a screen appears telling it is been started but then, nothing more happens. Screenshot: http://i.imgur.com/yYf4N8rl.png It isn't flashing the letter and numbers. Any help?