[FieldTrip] importing method for ft_crossfrequency() using our customized data format

[Casper van Heck]

Dear Ahn,

As background:

   1. Constructing your own format is easy, and is explained on the page "How
   can I import my own dataformat?
   <http://www.fieldtriptoolbox.org/faq/how_can_i_import_my_own_dataformat>"
   2. I'm assuming you're using the function 'ft_crossfrequencyanalysis',
   which doesn't seem to be embedded in a tutorial or anything similar. I do
   know that it wants the output of ft_freqanalysis, but if you want to know
   how it works, you're going to have to dive into the code.
   3. Working with Brainvision Recorder, you don't import the raw data
   directly; you direct Fieldtrip to the header file, and use ft_preprocessing
   to read all the data and the markers. If this goes awry, you can use the
   separate functions ft_read_header, ft_read_data, and ft_read_event to load
   those elements into memor  (more info here
   <http://www.fieldtriptoolbox.org/dataformat>). I seem to remember
   Brainvision events need to be read using ft_read_event anyway.

Importing data works best either through ft_preprocessing, or through
ft_read_data. You're trying to define a trial structure, but don't provide
a method to do that. Read the tutorial on preprocessing
<http://www.fieldtriptoolbox.org/tutorial/preprocessing>, and simply copy
the code used there, making a few changes to fit your data.

Good luck!

On 4 February 2016 at 03:20, 안민희 <tigoum at naver.com> wrote:

> 
>
> Dear community,
>
>
> My name is Ahn Min-Hee and I am working in the mindbrain lab in korea
> university, south koera
>
> on invasive BMI.
>
> Currently I am analyzing EEG data of our lab project, where we processed
> using our time-frequency
>
> analysis method on matlab. It's sourcing from Brain Vision Recorder.
>
>
>
> I tried using ft_crossfrequency() to assess time-frequency aspects of our
> data.
>
> First, I tried importing our own data that formed 3D type by frequency x
> time x channel,
>
> but I don't know how it convert the fieldtrip style data structure.
>
> Specially, about converting epoch dimension & constructing trial struct...
>
>
>
> So, I tried additional work as initiation. I import raw data such as
> *.eeg from Brain Vision Recorder.
>
> I work following:
>
>
>
> >> cfg = [] ;
>
> >> cfg.dataset='SSVEP_NEW_su0001.eeg';
>
> >> cfg.trialdef.eventtype='?';
>
> >> [cfg] = ft_definetrial(cfg);
>
>
>
> Warning: no trialfun was specified, using ft_trialfun_general
>
> > In ft_definetrial (line 135)
>
> evaluating trialfunction 'ft_trialfun_general'
>
> reading the events from 'SSVEP_NEW_su0001.vhdr'
>
> the following events were found in the datafile
>
> event type: 'Comment' with event values: 'actiCAP Data On'
>
> event type: 'New Segment' with event values:
>
> event type: 'Stimulus' with event values: 'S 11' 'S 12' 'S 13' 'S 14' 'S
> 15' 'S 16' 'S 21' 'S 22' 'S 23' 'S 24' 'S 25' 'S 26' 'S 28' 'S111' 'S112'
> 'S113' 'S114' 'S115' 'S116' 'S121' 'S122' 'S123' 'S124' 'S125' 'S126'
> 'S127'
>
> no trials have been defined yet, see FT_DEFINETRIAL for further help
>
> found 943 events
>
> created 0 trials
>
> the call to "ft_definetrial" took 0 seconds and required the additional
> allocation of an estimated 0 MB
>
> Then... I don't know that its result is correct or not... also, how treat
> warning & why resulting trial to 0.
>
> -----
>
> So, I summarize my question:
>
> 1. How convert/construct our own data format(freq x time x channel) to
> fieldtrip type data struct ?
> 2. What or where detailed example for ft_crossfrequency() function ?
> 3. How import *.eeg(brain vision raw data) ? Especially treat a trial
> information ?
>
> I uploaded our data formed file o a filehoster such as fieldtriptoolbox
> ftp site as it exceeds the
> critical file size of 1 MB. Here is the link:
>
> ftp://ftp.fieldtriptoolbox.org/pub/incoming/TiGoum_USIL.FREQxTIMExCHANNEL.mat
>
>
> Can someone tell me above questions. Any help world be appreciated.
> Thank you very much.
>
> Best,
>
> Ahn Min-Hee.
>
>
> _______________________________________________
> fieldtrip mailing list
> fieldtrip at donders.ru.nl
> http://mailman.science.ru.nl/mailman/listinfo/fieldtrip
>
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