[Eeglablist] Cleanline and Basic FIR filter

[Makoto Miyakoshi]

Dear Eric,

> The only major difference is that you define passband edges in
pop_eegfiltnew but half amplitude (-6 dB) cutoffs in the windowed sinc
filter.

For details, see below.
https://cloud.github.com/downloads/widmann/firfilt/firfilt.pdf
http://sccn.ucsd.edu/wiki/Firfilt_FAQ

Makoto

On Sun, Aug 30, 2015 at 11:20 AM, Andreas Widmann <widmann at uni-leipzig.de>
wrote:

> Hi Eric,
>
> > I have some questions about both cleanline and the basic FIR filter:
> >
> > 1) Do you have any recommendation about which one should be used first?
> At the moment I'm doing this (cleanline first and then bandpass filtering):
> Highpass filtering should be done before cleanline. Cleanline expects
> stationary data. See Nima’s recent paper for a more detailed explanation
> (Bigdely-Shamlo N, Mullen T, Kothe C, Su K-M and Robbins KA (2015) The PREP
> pipeline: standardized preprocessing for large-scale EEG analysis. Front.
> Neuroinform. 9:16. doi: 10.3389/fninf.2015.0001). Consider the „temporary
> highpass“-solution suggested there in applications not requiring a highpass
> otherwise.
>
> > [EEG, Sorig, Sclean, f, amps, freqs, g] = pop_cleanline(EEG,
> 'Bandwidth',2,'ChanCompIndices',[1:EEG.nbchan], ...
> >
>  'SignalType','Channels','ComputeSpectralPower',true,             ...
> >                           'LineFrequencies',[50 100]
> ,'NormalizeSpectrum',false,           ...
> >
>  'LineAlpha',0.01,'PaddingFactor',2,'PlotFigures',false,          ...
> >
>  'ScanForLines',true,'SmoothingFactor',100,'VerboseOutput',1,    ...
> >
>  'SlidingWinLength',EEG.pnts/EEG.srate,'SlidingWinStep',EEG.pnts/EEG.srate);
> >
> > EEG = pop_eegfiltnew(EEG, 1, 70, 1650, 0, [], 1);
> >
> > 2) I'm doing the filtering before epoching the data (on continuous
> data). Can that lead to any problem with the filtering?
> Filtering should always be done on the continuous data!
>
> > In cleanline: Both the 'SlidingWinLength' and 'SlidingWinStep' are the
> length of the recording. However, the 'SmootingFactor is 100, which
> shouldn't matter when the window length = EEG length.
> >
> > 3) Is there an easy way to figure out the filter order for
> pop_eegfiltnew? The current 1650 is just what was decided through the GUI.
> Use the windowed sinc FIR filter to manually adjust the filter order.
> pop_eegfiltnew is just a front-end for the windowed sinc filter with
> hardcoded hamming window and a default heuristic for filter order as
> explained in the help text. The only major difference is that you define
> passband edges in pop_eegfiltnew but half amplitude (-6 dB) cutoffs in the
> windowed sinc filter.
>
> Hope this helps! Best,
> Andreas
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-- 
Makoto Miyakoshi
Swartz Center for Computational Neuroscience
Institute for Neural Computation, University of California San Diego
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