find local minima within a time window of interest

To do the plot I have the X values and the Y values.

I need to find the local minima within a specific time-window (250-350) in the x axes.

How can I do it?

Answer 1

[Star Strider]

To find the minimum using findpeaks, multiply the first argument (‘y’) by -1 so the minimum becomes a maximum. Do not use the second argument as ‘x’ so that ‘locs’ returns an index. Then, use the ‘locs’ output with the original ‘x’ and ‘y’ vectors to get those values.

.

Answer 2

[Yongjian Feng]

You first need to figure out idx range of X for 250-350. Called them idx_start and idx_end.

Then just

min(Y(idx_start:idx_end))

[Melissa Jones]

Dont I need to use the function findpeaks?

[Melissa Jones]

How do I find those indexes?

[Yongjian Feng]

Try this:

idx_start = find(X>=250, 1);
idx_end = find(X>=350, 1);

Adjust the condition above whether you want X>= or just X>.

[Melissa Jones]

Thank you Yongjian, but i need to use the find_peaks function