Errors in tuto2_FFT openvibe while reading EEGdata from .csv

Working with OpenViBE signal processing scenarios and doing scenario/BCI design
Post Reply
NagarjunV
Posts: 9
Joined: Wed Feb 06, 2019 11:53 am

Errors in tuto2_FFT openvibe while reading EEGdata from .csv

Post by NagarjunV »

Hi all,

I am using EEG Cap; g.tec Mobilab+; g.Saharabox to obtain EEG data.

First, I recorded EEG data into csv file.
The, I tried to play openvibe box tutorials tuto2_FFT_filter. Instead of Generic stream reader, I replaced it to CSV file reader and kept epoch time duration 2 and intervel as 0.5 sec. I specified the path properly both Matlab working directory and Matlab executable file. I want to add noise at 6Hz frequency and display the signals. 5 errors are occuring while performing this scenario. They are:

[ ERROR ] At time 0.000sec <Box algorithm::(0*00006669, 0*00003b2c) aka csv file reader> : {Error discription} : {Error in header file. Details: First Column (Time:8*257:256) is not well formed}, {Errorotype::internal (code2)}, {Error location} : {C:\ovm\sdk\plugins\processing\file-io\src\box-algorithms\csv\ovpCBoxAlgorithmOVCSVFileReader.cpp::81}
[ ERROR ] {Error description} : {Box algorithm <TCP Writer> initialization failed}, {Error type} : {ErrorType::Internal (code 2)}, {Error location} : {C:\ovm\sdk\kernel\src\kernel\player\ovkCSimulatedBox.cpp::105}
[ ERROR ] {Error description} : {Failed to initialize player}, {Error type} : {ErrorType::Internal (code 2)}, {Error location} : {C:\ovm\sdk\kernel\src\kernel\player\ovkCPlayer.cpp::212}
[ ERROR ] The player could not be initialized.
[ ERROR ] The initialization of player failed. Check the above log message to solve the issue.

I am not understanding what these are...Can anyone suggest how to avoid these errors?

I am providing images below:
Attachments
ERROR
ERROR
3.JPG (58.19 KiB) Viewed 892 times
tut2 scenario
tut2 scenario
2.JPG (30.11 KiB) Viewed 892 times
FFT MATLAB script config
FFT MATLAB script config
1.JPG (68.32 KiB) Viewed 892 times

Thibaut
Posts: 144
Joined: Wed Oct 31, 2018 9:14 am

Re: Errors in tuto2_FFT openvibe while reading EEGdata from

Post by Thibaut »

Hi,
The color of the little triangle.^^
When you have record your csv the little triangle were green it's because your data were record as a streamed matrix. They lost the sampling rate information when the triangle is pink it's for signal data (with sampling rate) the format is not the same. change your record scenario. right click on csv writer box "input->input stream->configure" click on streamed matrix and choose signal.
Thibaut

NagarjunV
Posts: 9
Joined: Wed Feb 06, 2019 11:53 am

Re: Errors in tuto2_FFT openvibe while reading EEGdata from

Post by NagarjunV »

Thank You for your previous reply and Yes, you are right I took input as stream Matrix instead of signal. Now, it is working...I hope Openvibe describes the error in an easier way. Sometimes the errors it shows I don't understand it at all. Thank you again. :D.

I have another question:

I am a research student, and I am still learning. My aim is to build BCI system using SSVEP. I have created a 6Hz Flashing Channel and I recorded that data into CSV file. I need to display the peak value at 6 Hz frequency, which shows my BCI system can detect brain waves at 6hz out of all other noise. But what exactly is the use of adding noise at that frequency? In that tutorial given on the openvibe website, they have added noise at 20HZ frequency and displayed its peak value at 20Hz. What is the purpose of adding Noise? I have followed this website, they have not explained it properly.

http://openvibe.inria.fr/tutorial-using ... -openvibe/

Can anyone please explain this in detail?

Thibaut
Posts: 144
Joined: Wed Oct 31, 2018 9:14 am

Re: Errors in tuto2_FFT openvibe while reading EEGdata from

Post by Thibaut »

I feel that it is only an example.
Thibaut

Post Reply