selecting and extracting contiguous points as one event

I'm sure there is probably a drop-dead simple way to do this, but my brain is fried at the moment and I can't think of one. I'm trying to identify and count numbers of events that exceed a certain value in a time series. For example, a plot of the attached file yields:

I'd like to be able to count the number of events that exceed the red line (y=0.13). Sometimes there is 1 point > 0.13 (e.g. the first event above at x=40) and that is easy to count as a single signal. But sometimes there are 2 or more contiguous points > 0.13 (e.g. the second event above, at x=56, 57), yet should be counted as just one "event", not as 2 events.

How can this be done? I've attached a file with the above signal.

[nanren888]

Perhaps you could count the number of upward level-crossings?

Answer 1

[Andrei Bobrov]

let a - your data - vector.

out = sum(diff([0;a(:) > .13]) == 1);

[Stephen]

Oh wow, GREAT! Thanks Andrei!

Answer 2

[nanren888]

tt = linspace(0,12,1001);

s= sin(tt);

th = 0.4;

nnz(diff(s-th));

dd = [0,diff((s-th)>0)>0.5];

plot(tt,s,tt,dd);

grid('on');

nnz(dd)

ans =

2

[Stephen]

Thanks, nanren888! I'm having trouble applying your solution to a matrix of numbers (such as the excel spreadsheet that was attached with my Q) instead of a mathematical function such as the sin wave you show. sorry, I'm not as advanced as you are.

Answer 3

[Image Analyst]

If you have the Image Processing Toolbox, the simplest way is to just use the function that was made to do exactly that: bwlabel

[~, numRegions] = bwlabel(signal > 0.13);

Can't get any easier than that.

[Stephen]

Thanks, Image Analyst! I will investigate whether I can get the Image Processing Toolbox. In any case, the answer by Andrei Bobrov also worked well.

I appreciate this help.