Sum of both negative - positive part of a Peak

Dear ALL,

I have a peak that I woud like to take the integral of it, however, this peak has a positive (> 0 baseline) and negative part (< 0 beaseline).

So, is it any function in MATLAB that automatically sums both parts?

Please see attached the example...

Answer 1

[Star Strider]

Try this:

x = linspace(6.622, 9.644);
y = exp(-(x-mean(x)).^2/0.5) - 0.1;

Lv = y>=0;
PosPart = trapz(x(Lv), y(Lv))
NegPart = trapz(x(~Lv), y(~Lv))
SumParts = PosPart - NegPart

figure
plot(x, y)

Experiment to get different results.

[abaza]

Thank you so much for your quick response!

I will try to implement what you suggested in my "real work data", and I will come back to you for "accepting you answer"!

Cheers!

[Star Strider]

My pleasure!

EDIT — (25 Nov 2019 at 22:10)

Depending on what you want to do, this may be more accurate:

Lv = y>=0;
PosPart = trapz(x(Lv), y(Lv))
LT0 = trapz(x(~Lv), ones(size(x(~Lv)))*min(y))
NegPart = LT0 - trapz(x(~Lv), y(~Lv))
SumParts = PosPart - NegPart

Answer 2

[Image Analyst]

What if you sum the absolute value of the signal?

area = sum(abs(signal));

That will be the difference between the signal and the y axis.