[Eeglablist] remove DC offset

[Andrew Hill]

Thanks Søren,

I've been detrending before epoching - this should be less of a problem in distorting the epochs, I assume?

Best,
Andrew

On Mar 24, 2011, at 9:54 AM, Søren K. Andersen wrote:

> Hi Andrew and Baris,
> 
> if you only want to remove DC-offset, subtracting the mean of each epoch is the best:
> 
> EEG.data=EEG.data-repmat(mean(EEG.data,2),[1 EEG.pnts 1]);
> 
> Detrending also removes linear drifts. This is often a good idea for time-frequency analysis. However, detrending can cause major distortions when analyzing ERPs, especially if epochs are short!
> 
> Best,
> Søren
> 
> 
> On 23-Mar-11 5:35 PM, Andrew Hill wrote:
>> 
>> Hi Baris,
>> 
>> I'm not 100% sure what you are asking, but I use "detrend" to eliminate drift that's left in my DC recorded BDF files even after I convert them to EDF.
>> 
>> e.g.:
>> 
>> EEG.data = detrend(EEG.data);
>> 
>> Best,
>> Andrew
>> 
>> On Mar 21, 2011, at 4:50 AM, Baris Demiral wrote:
>> 
>>> Hi everyone,
>>> 
>>> Do you know which function is the "Remove DC offset" in the Display call for?
>>> 
>>> I was not able to track it out.
>>> 
>>> Thanks,
>>> Baris
>>> 
>>> -- 
>>> SB Demiral, PhD.
>>> Department of Psychology 
>>> 7 George Square
>>> The University of Edinburgh
>>> Edinburgh, EH8 9JZ
>>> UK
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>> 
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> 
> 
> -- 
> Søren K. Andersen, Ph.D.
> Department of Neurosciences
> University of California San Diego
> La Jolla, CA 92093
> Phone:(858) 534-1389
> Fax:  (858) 534-1566
> Email: skandersen at ucsd.edu

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