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How do you extract the Stimulus Frequncies from the data sets #54

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Gargablegar opened this issue Jul 27, 2016 · 4 comments
Open

How do you extract the Stimulus Frequncies from the data sets #54

Gargablegar opened this issue Jul 27, 2016 · 4 comments

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@Gargablegar
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I have looked at the datasets, and I want to use this data as extra data in experiments I am running which use a novel model based classification approach to SSVEPs in BCIs.

To make use of this data I need to have a value at which the stimulus is presented. In your data gathering method you indicate that the stimulus was randomised. I cant seem to see anywhere where the actual Frequency of the stimulus is record.

Any help with this would be great :)

@Gargablegar
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I see there is a Session.m file which segments the data according to experiment. A useful output would be something like an array of [Frequency presented, Start Sample, End Sample]

Could you perhaps point me to where you assign Frequency from the DIN data? For datasets I and II.

@Gargablegar
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I have used:
sess = eegtoolkit.util.Session;
sess.loadAll(1);

To extract this data, i will follow the comment i found in the code that says "%dont ask" :p

@liarosge
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Hi,

Yes you can use the method "split" of class "Session.m" to segment the Dataset I&II into trials of 5 sec duration which correspond to the stimulation period. Just be careful, there is a small difference between datasets I & II.

In the first dataset the stimulation frequency is calculated from the DIN_1 data (see "freqs" variable inside split).

In the second dataset there is a "labels" variable inside each .mat file which corresponds to the sequence of the stimuli.
1=12Hz
2=10Hz
3=8.57Hz
4=7.5Hz
5=6.66Hz

@Gargablegar
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I would just like to say I am using this toolbox and the PSDA classification portion as a benchmark comparison to the performance of my model based classification method.

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