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How to create auxiliary measures (aux)?

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New Member
Joined: 9 months ago

Good afternoon,

I am trying to preprocess the fNIRS records and in order to perform the first step of removing artifacts ("show excluded by channels") I read that it is necessary to have configured different auxiliary measurements (aux1, aux2, accelerometer...). I would like to know how I can create these auxiliary measures, because when I opena register with Homer3 I don't see any of them.

Thank you very much in advance.

1 Reply
Meryem Yücel
Posts: 195
Joined: 3 years ago

Dear Belen,

Typically the nirs instrument collects the auxiliary signals simultaneously with the fNIRS, and they would be saved under the snirf files as aux. Have you collected them separately? In that case, do you know the time offset between them? You will need to make sure either to extract the segment that is synchronous with the fnirs (or provide the offset time). Here are a few lines to, then, save it under a snirf file:

(You need to have homer3 on your matlab path.)

% load the snirf file

obj = SnirfLoad(filenm)

% set the fields to the auxiliary data acquired
obj.aux.dataTimeSeries = ...
obj.aux.time = ... = ...

% etc

% save it back

SnirfSave( filenm, obj )