How do I normalize this signal
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I have a noisy data set that I am trying to find peaks for (I am using the peakfinder function). The function works great when the baseline of the signal does not change, but when it does it no longer finds peaks well - I was thinking of filtering the data, but was unsure what kind of filter would actually help. Any help would be greatly appreciated. A sample below:
Accepted Answer
Star Strider
on 13 May 2014
I suggest a low-order bandpass filter, perhaps Butterworth 3 or 4. That will eliminate your baseline drift and most of the noise, making it much easier for findpeak to work.
6 Comments
More Answers (2)
Greg Dionne
on 13 May 2014
Since your peaks appear well-defined and are spaced far enough apart, I would suggest estimating the baseline by using medfilt1().
6 Comments
Greg Dionne
on 20 May 2014
Edited: Greg Dionne
on 20 May 2014
OK. It might be helpful to post your data file.
If you're not comfortable posting your data... maybe try something like:
[~,locs] = findpeaks(x-medfilt1(x,100),'MinPeakHeight',.01e4)
x(locs)
Image Analyst
on 13 May 2014
Some of those peaks are just barely above other peaks that don't have the red circle. Are you setting some threshold for how much a peak must exceed the "baseline" signal before it can be called a peak? What about using sgolayfilt() in the Signal Processing Toolbox. I have a demo available upon request.
2 Comments
Image Analyst
on 15 May 2014
Sounds like you don't even have an interest in even trying to understand, and have decided in advance that you "can't really use it" without understanding it. For example, you haven't attached your data file to let anyone help you by trying things.
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