Reading files .hdf5 creeated in gNautilus/gRecorder

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ammaia
Posts: 11
Joined: Tue Dec 04, 2012 12:15 pm

Reading files .hdf5 creeated in gNautilus/gRecorder

Post by ammaia »

Hi!
I'm using gNautilus32 device with gRecorder software to record EEG data. At the end the result is a file with ".hdf5" format.
Is there anyway to read it in OpenVibe?

I suppose not. So, I used Matlab to convert .hdf5 to .csv format but the new file created is not correct so I get an error.
Maybe someone has some experience about it...

Regards
Pedro Morais

ammaia
Posts: 11
Joined: Tue Dec 04, 2012 12:15 pm

Re: Reading files .hdf5 creeated in gNautilus/gRecorder

Post by ammaia »

Well, without any answers about this issue, I did a Matlab code to convert .hdf5 EEG data to .csv - compatible with OpenVibe.
If anyone need it just contact me.

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

Re: Reading files .hdf5 creeated in gNautilus/gRecorder

Post by Thibaut »

Hello,
Sorry I had to miss your message and forget to answer it. Indeed we do not read this kind of file. Level conversion, you did well, it is, I think, the best method. It's too late, but my only advice would have been that you look at how a basic csv is done with a dummy signal, like sinus oscillator, and reproduce that pattern in your script.

ammaia
Posts: 11
Joined: Tue Dec 04, 2012 12:15 pm

Re: Reading files .hdf5 creeated in gNautilus/gRecorder

Post by ammaia »

Thanks Thibaut!

But now I have a problem...
Using the "CSV Reader" + "Signal Display" to read the generated CSV file there are no animation at all.
The graph result is showed only at the end of time.

And the CSV file seems to be well formated... Do you know what can be wrong? (please look at attached file with the first lines...)
Attachments
OpenVibe_CSV_test.txt
(204.25 KiB) Downloaded 59 times

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

Re: Reading files .hdf5 creeated in gNautilus/gRecorder

Post by Thibaut »

The problem is the Epoch (second column),
For Example if your signal is in 512Hz, you have 32 Epoch Sample count. You increment your epoch number every 32/512 = 0,0625s.
Thibaut

ammaia
Posts: 11
Joined: Tue Dec 04, 2012 12:15 pm

Re: Reading files .hdf5 creeated in gNautilus/gRecorder

Post by ammaia »

Thanks!!! :D Problem solved.

Just one more question:
If my signal is 256Hz the Epoch Sample count should be 16?

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

Re: Reading files .hdf5 creeated in gNautilus/gRecorder

Post by Thibaut »

it's not mandatory, you can have as much sample as you want. By putting all the time the epoch to 0, you made an epoch with thousands of sample. ^^ By playing between the frequency and the sample count you play with the speed of refreshing.
Thibaut

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