P300 speller again

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Yueqing Li
Posts: 51
Joined: 08 May 2007, 16:41

P300 speller again

Post by Yueqing Li » 21 Jun 2007, 20:09

Dr Schalk, thank you so much for your help thus far.

We are still attempting to correctly run a P300 experiment. Please note that we have emailed you 2 different parameter configuration files as you have requested.

One of the configuration files is from the recommended P300 documentation tutorial. Please note that this file was not in BCI2000/src/Documentation/P3Speller (we have no src directory). Rather, it was found in BCI\doc\P300 Tutorial. This is your tutorial from 2003. We completely followed your P300 Tutorial, and when we attempted to 'Set Config' we received the following errors:

6/21/2007 6:48:21 PM - gUSBampADC::Preflight: Could not find appropriate pass band filter in gUSBamp. Use gUSBampgetinfo tool.
6/21/2007 6:48:21 PM - gUSBampADC::Preflight: Could not find appropriate notch filter in gUSBamp. Use gUSBampgetinfo tool.

When we attempted to use the gUSBampgetinfo tool located at BCI\tools\USBampgetinfo, a command prompt was displayed onscreen and then left at the speed of light - therefore we could not read the displayed information.

Please note that the other parameter configuration file (P300Custom.prm) displays no errors when 'Set Config' is pressed. P300Custom.prm is directly taken from the document "P300 Signal Acquisition and Analysis using Mario" found in BCI\doc\BCI2000 Workshop Handout (starting at page 145/186). However, P300Custom.prm is the file described to you in my last post that only displays 'A' regardless of what you are trying to spell. For example, 'HI' would result in 'AA'.

Aside from these problems.....
We cannot find any documentation about the MLR matrix. Anything we find only tells us to set it to 0 0 0 0 0 - with no reasoning or explanation. We do not know how to configure MLR beyond this...

We would appreciate any light you could shed on this :D
-Yueqing Li

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

P3Speller questions ...

Post by gschalk » 23 Jun 2007, 12:48


I think we cleared up most of your questions by going through your parameter file. Regarding your remaining question with the MLR matrix:

The MLR matrix can produce classification for a second control signal. This second control signal is not used by the P3Speller. Thus, the MLR matrix is irrelevant for the speller.

The Gerv


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