P300 Signal Processing

Forum for discussion on different signal processing algorithms
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nadoona
Posts: 14
Joined: 10 Aug 2007, 15:31

P300 Signal Processing

Post by nadoona » 18 Sep 2007, 04:04

Hi,

I was trying to understand P300 signal processing. I noticed that we keep going through 5 filters all the time while signals are being recorded. And the Classifier filter keeps computing an output signal in its Process function. However, I cant find where is the final control signal sent to the P3Speller application (telling it which character was selected). Where is the averaging of all the 30 intensifications done?

Please advise.

Thanks.

gschalk
Posts: 615
Joined: 28 Jan 2003, 12:37

P3Speller ...

Post by gschalk » 18 Sep 2007, 11:16

Nadoona,
I was trying to understand P300 signal processing. I noticed that we keep going through 5 filters all the time while signals are being recorded. And the Classifier filter keeps computing an output signal in its Process function. However, I cant find where is the final control signal sent to the P3Speller application (telling it which character was selected). Where is the averaging of all the 30 intensifications done?
The averaging is done in the P3TemporalFilter. Whenever it averages a signal, it sets StimulusCodeRes to the stimulus code of the averaged waveform. While the classifier classifies data on every call of Process(), the P3Speller application only evaluates the results when StimulusCodeRes is > 0.

Gerv

coolgee6
Posts: 1
Joined: 27 Nov 2014, 06:25

Re: P300 Signal Processing

Post by coolgee6 » 27 Nov 2014, 06:26

I have a question about how BCI does signal processing. I have the impression that it hands off functions like FFT or FIR filtering to Matlab that must then be running in the background. Is this right? If I am wrong, then any explanation that will help me understand how I went wrong will be very helpful.





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Last edited by coolgee6 on 18 Dec 2014, 05:45, edited 2 times in total.

boulay
Posts: 382
Joined: 25 Dec 2011, 21:14

Re: P300 Signal Processing

Post by boulay » 27 Nov 2014, 14:15

coolgee6 wrote:I have a question about how BCI does signal processing. I have the impression that it hands off functions like FFT or FIR filtering to Matlab that must then be running in the background. Is this right? If I am wrong, then any explanation that will help me understand how I went wrong will be very helpful.
It is possible to use Matlab to do the signal processing. To do so you must use "MatlabSignalProcessing.exe" as your signal processing module. Alternatively, and perhaps more commonly, you can use one of the other signal processing modules that come with BCI2000. For P300 tasks, for example, most people use "P3SignalProcessing.exe".

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