# Curve start and end coordinates

7 views (last 30 days)
ekagra gupta on 29 Aug 2022
Edited: Image Analyst on 30 Aug 2022
Hello,
I have a curve
I want to find the starting and end coordinates of these gaussian curves.
It would be great if you guys could help!
The required data is attached in this question itself ("req_data.mat").
Thank you!

Matt J on 29 Aug 2022
Edited: Matt J on 29 Aug 2022
Gaussian curves are infinite in length., so it isn't clear what your criterion would be for where they start/stop. However, a good place to start would probably be to use the Curve Fitting Toolbox to fit a three-term Gaussian model ( 'gauss3' ).
x=s.tau;
y=s.gamma_tau*1e4;
a=[1.5,0.5,6];
b=[-2,-0.3,1.4];
c=[1,0.5,1];
x0=[a;b;c];
ft=fit(x,y,'gauss3','StartPoint',x0(:).');
plot(ft,x,y)
Image Analyst on 30 Aug 2022
Edited: Image Analyst on 30 Aug 2022
The area in the tails is probably insignificant, therefore simply use the formula for the area of a Gaussian:
The area under a Gaussian curve equals Amplitude * StdDev / 0.3989
From Matt's code you know the 3 amplitudes and 3 standard deviations. It should be accurate enough for your purposes.

### Categories

Find more on Fit Postprocessing in Help Center and File Exchange

### Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by