[FieldTrip] cfg.trialfun in realtime functions

Stephen Whitmarsh stephen.whitmarsh at gmail.com
Thu May 10 14:51:56 CEST 2012


Dear Hamza,

The trialfunction is an integral part of processing data in FieldTrip.
It is how you define your timepoints of interest, i.e. trials based on
recorded markers in your data, or based on user-defined events (e.g.
sleep stages).

If you are not yet familiar with the basic FieldTrip operations the
documentation of the realtime analysis  might indeed seem somewhat
inadequate as it assumes this familiarity. FieldTrip's online analysis
tools are using many of the same functions of the offline ones, and
has a similar overall philosophy and approach. This makes it
relatively easy to understand and to use online analysis approach once
one is familiar with the offline one. Alas this translation is
assymmetric and doesn't hold for the other way around.

The good news is, however, that everything is there to get you on your
way once your take a little detour. You could take a look at the
tutorial documentation (http://fieldtrip.fcdonders.nl/tutorial) and
get a bit of hands-on working through some steps with the supplied
tutorial-data.

Specifically for your question these pages would be relevant:
http://fieldtrip.fcdonders.nl/example/getting_started_with_reading_raw_eeg_or_meg_data
http://fieldtrip.fcdonders.nl/tutorial/preprocessing
http://fieldtrip.fcdonders.nl/tutorial/continuous

For more overview and general operations I would advice reading through:
http://fieldtrip.fcdonders.nl/walkthrough

Most of all it might not be a bad idea to start with a pre-recorded
dataset and work on it offline, using the more standard and more
extensively documented offline functions for e.g. trial based
averaging. Once that works out for you can adapt it to the realtime
situation.

Hope this helps,
Stephen

On 10 May 2012 13:55, Hamza Fawzi Altakroury (Student)
<hamzaf at sabanciuniv.edu> wrote:
> Hello,
>
> I don't know why should I define a function inside the
> ft_realtime_selectiveaverage.
> I just want to make an average of some segments.
>
> Could you provide me with an example of cfg.trialfun
>
> Hamza
>
>
> On Wed, May 9, 2012 at 11:33 AM, Hamza Fawzi Altakroury (Student)
> <hamzaf at sabanciuniv.edu> wrote:
>>
>> Hello,
>>
>> I am doing realtime processing, and I wanted to check ft_realtime_average
>> function and ft_realtime_selectiveaverage functions.
>>
>> I faced a problem in defining cfg.trialfun
>>
>> Could you help me
>>
>> Best
>>
>> --
>> Hamza Fawzi Altakroury
>> Graduate student - MA
>> Faculty of Engineering and Natural Sciences
>> Sabanc─▒ University
>
>
>
>
> --
> Hamza Fawzi Altakroury
> Graduate student - MA
> Faculty of Engineering and Natural Sciences
> Sabanc─▒ University
>
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> fieldtrip mailing list
> fieldtrip at donders.ru.nl
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