Details of parameter file generated by P300classifier

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tinui
Posts: 16
Joined: 14 May 2015, 02:11

Details of parameter file generated by P300classifier

Post by tinui » 23 Aug 2015, 00:13

Hello.

I was trying to analysis data by using P300classifier.
I was inputting training data to P300classifier, and generated Feature Weights.
In addition, I generated parameter file by using Write*.prm file button,
but this generated parameter file was changed not only classifier parameter
but also other parameters (e.g: Epoch Length parameter, StimulusDuration parameter).
Why is it ? Can it be returned to the original value?
Please instruct me on what I should do.

Thank you.

pbrunner
Posts: 344
Joined: 17 Sep 2010, 12:43

Re: Details of parameter file generated by P300classifier

Post by pbrunner » 24 Aug 2015, 09:46

Tinui,

the weights of the linear classifier calculated by the P300Classifier tool [1] are specific to the stimulus timing. This is because the evoked responses to the stimuli are overlapping each other, as they are typically longer than the inter-stimulus interval. In addition, the weights depend on a certain signal processing pipeline. Hence you will find the in the parameter fragment the EpochLength, SpatialFilterType and TransmitChList in addition to the Classifier parameter.

If you don't want to adhere to these parameter, you have three options:

1) manually remove them from the .prm file
2) load a fragment with the parameters you like to use after the classifier .prm file
3) change the code in the \src\core\Tools\P300Classifier\WritePRM.cpp file to avoid writing these parameters into the .prm files

Regards, Peter

[1] http://www.bci2000.org/wiki/index.php/U ... Classifier

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