title: Calculating distance using a single camera
body: <p>I would like to calculate distance to certain objects in the scene, I know that I can only calculate relative distance when using a single camera but I know the coordinates of some objects in the scene so in theory it should be possible to calculate actual distance. According to the opencv mailing list archives, </p>
  
  <p><a href="http://tech.groups.yahoo.com/group/OpenCV/message/73541" rel="noreferrer">http://tech.groups.yahoo.com/group/OpenCV/message/73541</a></p>
  
  <p>cvFindExtrinsicCameraParams2 is the function to use, but I can't find information on how to use it?</p>
  
  <p>PS. Assuming camera is properly calibrated.</p>