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Reading files .hdf5 creeated in gNautilus/gRecorder

Posted: Mon Jul 01, 2019 2:12 pm
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

Re: Reading files .hdf5 creeated in gNautilus/gRecorder

Posted: Thu Jul 11, 2019 7:27 am
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.

Re: Reading files .hdf5 creeated in gNautilus/gRecorder

Posted: Thu Jul 11, 2019 8:26 am
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.

Re: Reading files .hdf5 creeated in gNautilus/gRecorder

Posted: Thu Jul 11, 2019 8:44 am
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...)

Re: Reading files .hdf5 creeated in gNautilus/gRecorder

Posted: Fri Jul 12, 2019 8:03 am
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

Re: Reading files .hdf5 creeated in gNautilus/gRecorder

Posted: Fri Jul 12, 2019 8:59 am
by ammaia
Thanks!!! :D Problem solved.

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

Re: Reading files .hdf5 creeated in gNautilus/gRecorder

Posted: Mon Jul 15, 2019 9:43 am
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