eog artifact rejection

Rodrigo A. Montefusco Siegmund rmontefusco at MED.UCHILE.CL
Wed Mar 25 22:51:12 CET 2009

Hello everyone

I'm trying to implement a script to detect and remove artifacts. One using
artifact_eog to eliminate artifacts in the EOG channels. I'm also looking
to eliminate a very large amplitudes in the signal.

The problem is that the script artifact_eog doesn't work on my dataset
derived from my own trialfun script.

Error in ==> fieldtrip-20080701\private\filetype at 225
[p, f, x] = fileparts(filename);

Error in ==> fieldtrip-20080701\private\dataset2files at 66
  switch filetype(cfg.dataset)

Error in ==> artifact_zvalue at 155
cfg = dataset2files(cfg);

Error in ==> artifact_eog at 137
  [tmpcfg, artifact] = artifact_zvalue(tmpcfg);

My raw data is obtained from an amplifier built in my laboratory, so we
collect data very raw, without file header or anything similar.

The file .dat is turned to .mat, then that file is loaded to the
workspace, and then I process it with my trialfun. with that, I create a
structure "data" which contains

data =
       trial: (1x60 cell)
       label: (1x24 cell)
     fsample: 250
        time: (1x60 cell)

in the format for fieldtrip. also generates a hdr

hdr =
                     Fs: 250
                 nChans: 24
               nSamples: 750
            nSamplesPre: 250
                nTrials: 60
                  label: (1x24 cell)
         FirstTimeStamp: 1
     TimeStampPerSample: 1

and the trl that is requested by the documentation.

How can I use the artifact_eog on data generated in the format that I
mentioned above?

Thanks a lot and excuse my english

best regards


Rodrigo A. Montefusco Siegmund
Doctorado en Ciencias Biomédicas
Programa de Fisiología y Biofí­sica
I. C. B. M. Facultad de Medicina
Universidad de Chile
Centro de Neurociencias Integradas
Iniciativa Cientí­fica Milenio
Fono: 56 09 82793847
email:  rmontefusco at med.uchile.cl

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