Import the markers

[faisal]

Hi every one

I am working on P300 signals and I used brain vision System to record the signals. Now i want to Import the markers file (obtained in the brain vision software) to the matlab to analyze the signal.

Please tell me how i could do this ?



Best regards
Faisal

[yrenard]

Dear faisal,

thank you for your interest in OpenViBE and welcome on this forum. Please note that your question is not related in OpenViBE !

The markers files recorded by Brain Vision Recorder are simple text files. I'm not familiar with Matlab but I know there are several functions to open and read text files. Please dig the Matlab documentation this way.

Yann

[faisal]

Thanks alot for the reply

i solved this problem .


i want to ask you about the averaging of P300 data. I have recorded the data , and i now i want to detect P300 signal . please tell me how to do this averaging when we knows from theory that P300 evoked after 300ms , it means that we have many P300's in our data. For my case , i use 15 time character repetion (i,e: means i would have 30 P300's of my required character overrall).

How i would do my data's averaging to see one data equalient from all those 30 P300 's in this regard . Because in between time of occurance of P300 is difficult to judge.

I hope u understand my Problem.

Thanks in advance


Best Regards

[yrenard]

Dear faisal,

it's nice that you got this working.

About the averaging question, don't forget OpenViBE is not devoted to offline analisys. Its primary purpose is to process data online.
In order to average multiple ERP signals, you will have to use the Epoch Average box. Have a look to the P300 sample scenarios for examples of how to use them for P300 averaging.

Regards,
Yann

[faisal]

Thanks alot

Can u please let me knoe how i can configure Openvibe with Brain vision software ?




Best regards

[yrenard]

Dear faisal,

please check this page in order to know how the OpenViBE acquisition server works. You will be able to chose the driver that best fits your needs. By the way, I recommend that you use dedicated driver if your device is natively supported by OpenViBE instead of using Brain Vision Recorder.

Hope that helps,
Yann

[olivierjoly]

Dear All,
It seems I have a problem to import my markers from BrainAmp File header for computing later ERP.
Should I use a specific name of Marker ? I have tried with Label_00 and with OVTK_StimulationId_Label_00 but it seems I always get
'not supported'.
I guess I will have the same problem for online analysis with direct connection to the BrainVision Recorder.
Any ideas ?
Many thanks!
Olivier
Here is a list of warnings :
[WARNING] <Algorithm::Brainamp file reader> Header specifies code page as UTF-8 but it will be forced back to ANSI
[WARNING] <Algorithm::Brainamp file reader> Marker [New Segment:] is not supported. Therefore it will be ignored
[WARNING] <Algorithm::Brainamp file reader> Marker [OVTK_StimulationId_Label_00:] is not supported. Therefore it will be ignored
[WARNING] <Algorithm::Brainamp file reader> Marker [R:R 1] is not supported. Therefore it will be ignored
[WARNING] <Algorithm::Brainamp file reader> Marker [OVTK_StimulationId_Label_00:] is not supported. Therefore it will be ignored
[WARNING] <Algorithm::Brainamp file reader> Marker [OVTK_StimulationId_Label_00:] is not supported. Therefore it will be ignored
[WARNING] <Algorithm::Brainamp file reader> Marker [R:R 1] is not supported. Therefore it will be ignored
[WARNING] <Algorithm::Brainamp file reader> Marker [Deviant_a:D 1] is not supported. Therefore it will be ignored
[WARNING] <Algorithm::Brainamp file reader> Marker [OVTK_StimulationId_Label_00:] is not supported. Therefore it will be ignored
[WARNING] <Algorithm::Brainamp file reader> Marker [R:R 1] is not supported. Therefore it will be ignored
[WARNING] <Algorithm::Brainamp file reader> Marker [OVTK_StimulationId_Label_00:] is not supported. Therefore it will be ignore

[yrenard]

Dear olivierjoly,

thank you for your interest in OpenViBE and welcome on this forum.

Actually, you should not have the same problem with BrainVision Recorder.
By the way, the markers that can be read from BrainAmp Files are only Stimulus markers.

The syntax in the marker file should be as follows :

Code: Select all

Mkn=Stimulus,S x, position, duration, channel, date

The output OpenViBE stimulation code will be OVTK_SimulationLabel_00 + x.

Here is a sample marker file that could be read from this box :

Code: Select all

Brain Vision Data Exchange Marker File, Version 1.0

[Common Infos]
Codepage=UTF-8
DataFile=OVP300_JBE_0002.eeg

[Marker Infos]
; Each entry: Mk<Marker number>=<Type>,<Description>,<Position in data points>,
; <Size in data points>, <Channel number (0 = marker is related to all channels)>
; Fields are delimited by commas, some fields might be omitted (empty).
; Commas in type or description text are coded as "\1".
Mk1=New Segment,,1,1,0,20081212142006102060
Mk2=Stimulus,S  6,17754,1,0
Mk3=Stimulus,S  8,17971,1,0
Mk4=Stimulus,S  2,18187,1,0
Mk5=Stimulus,S 10,18404,1,0
Mk6=Stimulus,S  4,18621,1,0
Mk7=Stimulus,S  7,18837,1,0
Mk8=Stimulus,S  5,19054,1,0
Mk9=Stimulus,S  9,19270,1,0
Mk10=Stimulus,S  3,19487,1,0
Mk11=Stimulus,S  1,19704,1,0
Mk12=Stimulus,S 11,19920,1,0
Mk13=Stimulus,S 12,20137,1,0
Mk14=Stimulus,S 12,20354,1,0
Mk15=Stimulus,S  6,20570,1,0
Mk16=Stimulus,S 10,20787,1,0
Mk17=Stimulus,S  3,21004,1,0
Mk18=Stimulus,S  7,21220,1,0
Mk19=Stimulus,S  1,21437,1,0
...

Note that Mk1 will be skipped as it is not a Stimulus.

Hope this helps,
Best regards,
Yann

[olivierjoly]

Dear Yann,
Thanks a lot, I got it !
It seems to work for me, just have to find out how to display online averaging of my ERP.
Best regards
Olivier

[yrenard]

Dear Olivier,

the Epoch Average box is probably what you are looking for

Hope that helps,
Regards,
Yann