title: Need help with peak signal detection in Perl
body: <p>Hi everyone I have some values of intensities from images of yeast colony plates.  I need to be able to find the peak values from the intensity values.  Below is an example image showing how the values look when graphed.  </p>
  
  <p><strong>Example of some of the values</strong> </p>
  
  <pre>
  5.7
  5.3
  8.2
  16.5
  34.2
  58.8
  **75.4**
  75
  65.9
  62.6
  58.6
  66.4
  71.4
  53.5
  40.5
  26.8
  14.2
  8.6
  5.9
  7.7
  14.9
  30.5
  49.9
  69.1
  **75.3**
  69.8
  58.8
  57.2
  56.3
  67.1
  69
  45.1
  27.6
  13.4
  8
  5
  </pre>
  
  <p>These values show two peaks at 75.4 and 75.3, you can see that the values increase then decrease.  The change is not always the same.</p>
  
  <p><strong>Graph of intensity values</strong></p>
  
  <a href="http://picasaweb.google.com/lh/photo/M6KxZBZM82E5cKcBPm-hmg?feat=embedwebsite" rel="nofollow noreferrer">http://lh4.ggpht.com/_aEDyS6ECO8s/THKTLgDPhaI/AAAAAAAAAio/HQW7Ut-HBhA/s400/peaks.png</a>From <a href="http://picasaweb.google.com/alos31/Research?feat=embedwebsite" rel="nofollow noreferrer">research</a>
  
  <p>One of the things that I am thinking of doing is to store each of the groups i.e. mountains in a hash then look for the largest value in a group.  One if the issues that I am seeing though is how to determine the boundaries of each of the groups.</p>
  
  <p>Here is a link to the code that I have so far:
  <a href="http://paste-it.net/public/y485822/" rel="nofollow noreferrer">http://paste-it.net/public/y485822/</a></p>
  
  <p>Here is a link to a complete data set:
  <a href="http://paste-it.net/public/ub121b4/" rel="nofollow noreferrer">http://paste-it.net/public/ub121b4/</a></p>
  
  <p>I am writing my code in Perl.  Any help would be greatly appreciated.  Thank you</p>