[FieldTrip] general questions about the FieldTrip
mor2451 at gmail.com
Sun Mar 29 14:11:38 CEST 2015
thanks a lot Robert
one more question if i may: are there any spesific set of functions on
Matlab FieldTrip or even a sequence of algorithms in order to make P300
extractions for my p300 speller?
On Fri, Mar 27, 2015 at 6:53 PM, Robert Oostenveld <
r.oostenveld at donders.ru.nl> wrote:
> Hi Moran
> 1) The fieldtrip buffer by itself has a delay that can be as small as 5ms.
> But the actual delay in the data stream from the electronics to the MATLAB
> side of the buffer depends on quite a number of parameters and can be much
> larger. Sending data in blocks (i.e. multiple samples are bufferend and
> sent in one go), bluetooth and USB all cause delays before you are able to
> process the samples in the data block. Even the USB connection and whether
> you are sharing it with another device (i.e. mouse or USB hard drive on the
> same USB hubor port) can affect the delay and can cause jitter (variation
> in the delay). I suggest you look at
> for a demonstration how you can quantify the That page has data for our CTF
> MEG system, which has a blocksize of ~100ms and does some online processing
> (head localization) prior to forwarding the data, hence the delay of 150ms
> that we see here makes sense.
> 2) On http://www.fieldtriptoolbox.org/getting_started/realtime you can
> find some getting started instructions. Reading data from a file rather
> than from a realitme buffer just means that you specify the name of the
> file. If you look at
> http://www.fieldtriptoolbox.org/example/ft_realtime_signalviewer you can
> see how you can simulate a real time data stream. Just replace cfg.dataset
> with an EEG file name in ft_realtime_signalviewer and you are not plotting
> real time data, but data from file.
> 3) your P300 application can send events to the fieldtrip buffer and the
> signal processing application can read them and act upon the data referred
> to in the events. You can also make a single application that does both, or
> make two applications that communicate events separate from the data stream.
> 4) I recall that some emotiv software needed to be installed, but don’t
> know whether that requires the full SDK to be installed. I don’t have an
> emotiv epoc myself. Please see
> http://www.fieldtriptoolbox.org/development/realtime/emotiv and feel free
> to add your findings to that (wiki) page.
> best regards,
> On 27 Mar 2015, at 16:28, moran abilea <mor2451 at gmail.com> wrote:
> > hi again,
> > i have another question/s, but this time they are genra.
> > but first let me explain what i need from field trip: i'm working for
> extracting from 14 channels EPOC Emotive the EEG raw data as contious data,
> send trigger if i want to display the raw data or not and then process the
> data with SVM. all this process is for creating EEG speller in Matlab.
> > so my questions are:
> > 1. i assume the field trip has constant "delay", the delay i reffer to
> is between the time of view the signal and the real time data transfer in
> the buffer. does anyone knows what is the delay time somehow?
> > 2. where can i find how to open stream for a file?
> > 3. using triggers: can i send time stamp in my configuration in order to
> know when to display the data that i need for the EEG speller?
> > 4. what to do in order to use the EPOC Emotive? do i need to set some
> new configurations for matlab? to download any SDK? etc
> > any kind of help will be welcomed,
> > Moran Abilea
> > _______________________________________________
> > fieldtrip mailing list
> > fieldtrip at donders.ru.nl
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