how to change the EEG signals into sound signals ?

[faiz_ulrich]

how to change the EEG signals into sound signals ?

Hi there,

I am a beginner, I want to ask you some questions about OpenVibe...

1. Can openvibe working with EEG offline data signals??, if so, how to configure it at OpenVibe??
2. how to change the EEG signals into sound signals ??, i'm blind of this...

thanks very much before...

regards,
faiz

[lbonnet]

Hello faiz, and welcome on board !

I saw you just posted your message in 3 topics, but 1 is enough... We are wandering the forum pretty much all the time and we try to answer quickly. Your questions won't be lost

1. Can openvibe working with EEG offline data signals??, if so, how to configure it at OpenVibe??

Yes indeed. OpenViBE can be used in offline or online mode.
To use openvibe offline, you need prerecorded EEG data files. The current available format are GDF, BCI Competition IIb files, Brainamp format, CSV or openvibe native format. the software includes some EEG files if you want to run some tests. Look at the files in /share/openvibe-scenarios/. There is xml scenario files to open with the Designer, and EEG data files to read for offline treatment. To read these data, just use the corresponding box ! (under File reading and writing).

2. how to change the EEG signals into sound signals ??, i'm blind of this...

Good question... So far, we don't have any box that could do the trick. If you need to translate EEG signal into sound signal, I guess it's possible with a translation of the frequency spectrum in the sound frequencies (much higher freq) One problem that will come is the sampling rate : EEG for BCI purpose has around 500 Hz sampling frequency. Your sound card will need sound sampled at 40kHz or more I think (interpolation needed ?).

Feel free to contribute by writing a new openvibe box for that job
You can count on our support for the development

Regards,

Laurent-

[faiz_ulrich]

thanks for the reply

My research actually will be implemented for 3 months after this,
and my research related to the development of BCI with OpenVibe.

maybe after this, will a lot of questions from me about the question "how to change the EEG signals into sound signals"
thanks for the help
do you have a journal in relation to my question earlier??

Can I ask for your personal email ?
so I can contact you other than the forum and mailing list....

regards,
faiz

[lbonnet]

do you have a journal in relation to my question earlier??

Sorry but I don't have any article to give you right now. Our work here is to develop the OpenViBE software, and help the BCI community to use it and contribute. I will only give some ideas we had regarding openvibe and sound signals.
One solution (thank my PhD coworker ) could be :

• - FFT for the transformation (temporal to frequential)
  - spectrum translation and dilatation (e.g. 0-20hz band to 100-1000Hz)
  - inverse FFT (frequential to temporal)
  - Upsampling (e.g. 512 hz eeg to 44KHz sound signal)
  - Sending the signal to a sound card

I'm not sure when the upsampling has to be done. Maybe after the FFT.

This is just a basic idea that you could think over. I guess you will need to google a little bit more if you want precise answers and algorithms, as we won't be helping much more. Our work is hardly focused on the development of the platform.
Once you have your algorithms, and the signal processing chain, you could implement several openvibe boxes enclosing the algorithms. And we could help you for that.

Can I ask for your personal email ?
so I can contact you other than the forum and mailing list....

Sorry I can't give you my personal email. It will become impossible to work if everyone is mailing me
I recommend you to read the tutorials, for the installation procedure and box development. Moreover the forum is here for you, as any further questions you may have will be useful for the community !

Best regards,

Laurent-