How do I find peaks from a graph which I plotted from analyzing a video file?

I have a video file which I am analyzing- I have split my video into frames, and then checked each frame for gray levels and plotted my results in a graph. I would like to find the peaks in this graph and eventually find distance between the peaks and frequency of the peaks.

The documentation says I need to do something similar to this :

 load sunspot.dat
 year=sunspot(:,1);
 relNums=sunspot(:,2);
 findpeaks(relNums,year);
 xlabel('Year');
 ylabel('Sunspot Number')
 title('Find All Peaks');

How would I go about this? I realise I need to use findpeaks(), but I am not sure what to put in the brackets because I don't actually have a file full of data.

Answer 1

[Image Analyst]

You don't need a file. findpeaks() takes an array. Just do this

[peakGrayLevel, indexOfPeaks] = findpeaks(yourGrayLevelVector);