title: How to do the correspondance 2D-3D points
body: <p>I'm working with <strong>OpenCv API</strong> on an augmented reality project using one camera.I have :</p>
  
  <ul>
  <li>The <strong>3D point</strong> of my 3D object( i get 4 points from MeshLab)</li>
  <li>The <strong>2D points</strong> which i want to follow ( i have 4 points):these points are not the projection of the 3D points.</li>
  <li><strong>Intrinsic</strong> camera <strong>parameters</strong>.</li>
  </ul>
  
  <p>Using these parameters, i have the <strong>extrinsic parameters</strong>( rotation and translation using the <strong>cvFindExtrinsicParam</strong> function) which i have used to render my model and set the <strong>modelView matrix</strong>.
  My problem is that the 3D model are not shown in particular position: it has been shown in différent location on my image. How can i fix the model location and then the modelView matrix? 
  In other forums they told me that i should do the correspondance 2D-3D to get the extrinsic parameters but i don't know how to correspond my 2D points with the 3D points?</p>