title: What are the main references to the fish-eye camera model in OpenCV3.0.0dev?
body: <p>I am wrestling with the <strong>Fish-Eye Camera Model</strong> used in <strong>OpenCV 3.0.0.dev</strong>. I have read the documentation in this <a href="http://docs.opencv.org/master/db/d58/group__calib3d__fisheye.html" rel="noreferrer">link</a>  several times, especially the <strong>"Detailed Description"</strong> part and formulas modeling fish-eye distortion. By now I have two concerns: </p>
  
  <ol>
  <li><p>Based on the projection models listed <a href="http://wiki.panotools.org/Fisheye_Projection" rel="noreferrer">here</a> and their conceptual explanations in "<strong>Accuracy of Fish-Eye Lens Model</strong>" By Hughes, I can't figure out which <strong>projection model</strong> has been used in the OpenCV implementation. </p></li>
  <li><p>Since the description is so concise, I need to know <strong>the main reference papers</strong> used by OpenCV developers for implementing  fish-eye namespace, so that I could be on the ball and get through more details. 
  P.S. I checked OpenCV 3.0.0-dev documentation and did not find anything useful.  </p></li>
  </ol>