title: What are the second-moments of a region?
body: <p>I'm currently working on replicating some of the functionality of Matlab's regionprops function in Octave.  However, I have a bit of a hangup on a subset of the functionality.  The 'Eccentricity', 'MajorAxisLength', 'MinorAxisLength' and 'Orientation' properties are my sticking point.  In the documentation, they all derive from "...the ellipse that has the same second-moments as the region."</p>
  
  <p>So my question is, what are these second-moments, and how do I find them?</p>
  
  <p>I was looking at this link:
  <a href="http://en.wikipedia.org/wiki/Image_moments" rel="noreferrer">http://en.wikipedia.org/wiki/Image_moments</a></p>
  
  <p>Honestly, it's just left me more confused.  Can anyone point me towards something a little more beginner friendly?  Thanks.</p>