Get envelope of multiples curve

Dear all Any idea about the envelope of 2 or more curves via Matlab; Please see the attached Xls file Thanks

[Star Strider]

No file 5 hours later.

When you use the ‘paperclip’ icon be sure to complete both the ‘Choose file’ and ‘Attach file’ steps.

[John BG]

After you click on the 'clip' to attach you have to 'Choose file' and actually attach it by clicking on the 'Attach file button'

[Lila wagou]

Any help please

[Roger Stafford]

@Lila: The word 'envelope' is not appropriate for "fitting" a curve to a finite number of other curves. You need a precise definition of the curve you are seeking if you want matlab to determine it.

Answer 1

[Star Strider]

With your data, I would simply use the min and max functions:

d = xlsread('Lila wagou 3_Curves.xlsx');

t = d(:,1);
data = d(:,2:end);

env = [min(data,[],2)  max(data,[],2)];

figure(1)
plot(t, data)
hold on
plot(t, env(:,1), '-g', 'LineWidth',2)
plot(t, env(:,2), '-g', 'LineWidth',2)
hold off
grid

[Lila wagou]

Thank you Star Strider, it's work 10 by 10

[Star Strider]

My pleasure!

[Anand]

Is there a way to characterize lets say 1k graphs, and then any new series that's added can be approved/rejected based on it being inside the envelope?

[Star Strider]

@Anand — This makes no sense to me.