how to find peaks

I want to find peaks from a plot, but I won't to use "findpeaks".

my professor told me to create a treshold in certain point and then count the peak as a region with "imfill".

I still didn't know ho to execute that, can someone give me some advice.

Here is an example code:

x=linspace(1,10);
y=sin(2*x);
plot(x,y)

Answer 1

[Dyuman Joshi]

I don't see how imfill would work with curves and plots (unless saved as an image, of course).

findpeaks finds the local maxima.

So, a simple workaround is to use islocalmax paired with logical indexing -

x=linspace(1,10);
y=sin(2*x);

idx = islocalmax(y);

plot(x,y)
hold on
plot(x(idx), y(idx), '*', 'MarkerSize', 10)
legend({'function', 'peaks'})
ylim([-1.2 1.2])