Identifying periods of signal above threshold

The code below provides number of "bursts" or periods of activity (300 consecutive points = 0.2 s) above a given threshold. How could I add a further condition to the code that identifies "bursts" only when there are at least n values of separation (i.e. 1200 points) (below the threshold) between two different bursts?

      above_threshold = (signal > threshold);
      minAcceptableLength = 300;
      % Find spans that are long enough.
      isLongEnough = bwareafilt(above_threshold, [minAcceptableLength, inf]);
      % Count the number of spans (bursts) that are long enough.
      [labeledSpans, numberOfBursts] = bwlabel(isLongEnough);

Answer 1

[Image Analyst]

You'd have to look at the inverse: ~isLongEnough. Then call regionprops() to measure the lengths of all the stretches/gaps between the bursts. Then take some action depending on whether they are long enough or not.

labeledLowSignalRegions = bwlabel(~isLongEnough);
props = regionprops(labeledLowSignalRegions, 'Area');
allLengths = [props.Area]

[Antonio Morales]

Thank you, it seems to give me what I want. Nonetheless, I am not sure if I am correctly taking the number of bursts.

As an example: 70 bursts have been identified in one of the signals.

Here are all lengths of each burst (above threshold) and gap between burst (below threshold) identified:

LengthsAboveThreshold = [3296  423  1715  1189  309  536  209  364  13778  1973  1847  8843  1329  3627  6274  375  252  204  338  841  519  1454  2597  215  203  463  277  5205  404  236  722  526  367  283  931  2387  306  221  371  265  272  205  274  331  392  238  219  222  222  3192  473  708  212  213  207  2830  373  281  2074  301  232  313  854  1776  255  201  218  200  307  5155]; 

LengthsBelowThreshold = [1717085  14  2  36  15  140  72  13  32  47  15  24  22  18  14  39  59  7529427  465416  37  23800  10  76680  551  745  12753  27  9  1116106  9  40  137  37  34  75  27  272  134918  192  1139  166  868  171  533  293  205  275  21061  153  20  4  105  82  32  31151  49  30  1936  108560  167  59999  412  18  7  54  707  6960  243  52480  76  2605663];

Let's suppose want to quantify the number of bursts that have a gap of at least 1200 points between them. Would it be right just doing the following:

idx = find(LengthsBelowThreshold >= 1200);
numberOfBursts = length(idx);

Thank you