[Homer-users] examples of using the prune_channels function?

[Sabrina Brigadoi]

Hi Erin,

the values for the enPruneChannel function are highly dependent on your
data. The first parameter are two thresholds: one is the low one and one is
the upper one. They depend on the intensity of your raw data. If a channel
as a mean value above the upper threshold, it will be labeled as noisy. If
a channel has a mean value smaller than the low threshold, it will be
labeled as noisy. I usually leave the upper threshold as it is set as
default and I change the low threshold based on my data. You have to look
at the y-axis value of your raw data and detect the suitable threshold for
your data, to remove the noisy channels usually displayed at the bottom of
the window, if any. The second parameter of the function is the SNR
threshold: every channel with SNR smaller than the SNR threshold is labeled
as noisy. I usually prefer to play only with the amplitude thresholds, thus
I set the SNR one to zero. The default parameter (2) is also ok. But again,
it depends on your data.

And yes, the channel removed with this function will be skipped in the
subsequent analysis.

Sabrina

--
Sabrina Brigadoi
PhD Student
DPSS, University of Padova, Italy
Room 028, Via Venezia 15, Padova
Phone: (+39) 049 8276402
sabrina.brigadoi at studenti.unipd.it

Cognition and Language Research Laboratory
http://colab.psy.unipd.it


2013/3/12 Erin Solovey <erinsol at mit.edu>

> Hi,
>
> Are there any examples for using the prunce_channels function. What
> values are typically put in as parameters? In the user's guide, the
> sections on this are "TBA".
>
> Also, if a channel gets removed in one data file, how does that affect
> the group calculations? Will it just be skipped?
>
> Thanks!
> Erin Solovey
>
> --
> Humans and Automation Laboratory
> Massachusetts Institute of Technology
> Cambridge, MA 02139
> http://people.csail.mit.edu/erinsol
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-- 
Sabrina Brigadoi
sabrina.brigadoi at gmail.com
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