title: How can you tell if a homography matrix is acceptable or not?
body: <p>When using OpenCV's <code>findHomography</code> function to estimate an homography between two sets of points, from different images, you will sometimes get a bad homography due to outliers within your input points, even if you use RANSAC or LMEDS.</p>
  
  <pre><code>// opencv java example:
  Mat H = Calib3d.findHomography( src_points, dst_points, Calib3d.RANSAC, 10 );
  </code></pre>
  
  <p>How can you tell if the resulting 3x3 homography matrix is acceptable or not?</p>
  
  <p>I have looked for an answer to this here in Stackoverflow and in Google and was unable to find it.</p>
  
  <p>I found this article, but it is a bit cryptic to me:</p>
  
  <p><a href="http://perception.inrialpes.fr/Publications/2005/CPS05/" rel="noreferrer">"The geometric error for homographies"</a></p>