Stimulation based epoching cannot work on overlapped signals

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RadhaKumari
Posts: 27
Joined: Wed Nov 14, 2018 6:10 pm

Stimulation based epoching cannot work on overlapped signals

Post by RadhaKumari »

I recorded data using Open BCI Ganglion via LSL and saved it in a CSV file. I am trying to process the data using Stimulation based epoching to extract segment after one particular stimulus. I am getting the error: Stimulation based epoching cannot work on overlapped signal. What do I make out of it?
Last edited by RadhaKumari on Fri Nov 16, 2018 10:39 am, edited 1 time in total.

jtlindgren
Posts: 778
Joined: Tue Dec 04, 2012 3:53 pm
Location: INRIA Rennes, FRANCE

Re: Stimulation based epoching cannot work on overlapped sig

Post by jtlindgren »

Hi,

the stimulation based epoching only works on continuous streams apparently. Such streams have data chunks with each having timestamps like

Code: Select all

chunk:    1   2    3    4   ...
stamp: [a,b][b,c][c,d][d,e] ... 
and so on. The end of previous chunk must exactly match in time to the start of the next chunk. You can use e.g. EBML stream spy to investigate these stamps.

It is possible that the csv format with its finite precision (typically smaller than what ov uses internally) introduces rounding error or something that makes the box think them as noncontinuous. You can use the .ov format to avoid this issue.


Cheers,
Jussi

RadhaKumari
Posts: 27
Joined: Wed Nov 14, 2018 6:10 pm

Re: Stimulation based epoching cannot work on overlapped sig

Post by RadhaKumari »

Yes, when I changed to generic stream writer and used stimulation based epoching, it was no longer an issue.
Thanks

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