How to measure overlap area of peaks from different signals

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Hi All, I wonder if there is a simple way to solve the following problem. There are two time-series signals S1 and S2 from two sensors and the signals were collected by the same frequency and time scale. If there are n peaks in S1 and m peaks in S2, how much area of peaks in S1 is overlapped with peaks in S2? Thanks in advance! Wenlong

Accepted Answer

Star Strider
Star Strider on 6 Aug 2014
I’m not quite certain what you want, but if you want the total overlap of the peak areas, use trapz (or cumtrapz) and subtract:
% Create Data:
pk = @(m,s,x) exp(-(x-m).^2./s); % Create peaks with centre=m, width=s
x= linspace(0,20);
s1 = pk(5,2,x) + pk(11,3,x) + pk(17,2,x);
s2 = pk(7,2,x) + pk(12,2,x) + pk(15,2,x);
% Integrate, Then Subtract:
Is1 = cumtrapz(x,s1);
Is2 = cumtrapz(x,s2);
Isd = Is1 - Is2;
figure(3)
plot(x,Isd)
grid
The final value of ‘Isd’ is the difference in the areas of the peaks between the two data vectors, ‘s1’ and ‘s2’.
Is this what you want to do?
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More Answers (1)

Salaheddin Hosseinzadeh
Salaheddin Hosseinzadeh on 6 Aug 2014
Hi Wenlong,
You didn't explain the problem in detail, so you probably looking for an idea.
What I understood and I would do is:
1- Define what's the accepted signal level as a peak (you may wanna use FWHM or any preferred definition), lets call it "threshold".
2- peakAreaS1 = S1 > threshold;
3- peakAreaS3 = S2 > threshold;
4 - overlapedArea = peakAreaS1 & peakAreaS2;
Hopefully this is a good enough hint.
Good luck!

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