title: Z coordonate from intrinsic matrix and inverse disparity map in OpenCV
body: <p>I am facing the challenge to recover the Z coordinate from an inverse disparity map and the camera matrix K. The Z coordinate does not have to be metric but it has to be scale aware.</p>
  <pre><code>K = [[721, 0, 596],
       [0, 721, 149],
       [0, 0,     1]
  </code></pre>
  <p>I know that z=f*(T/d) where T is the distance between two co-planer cameras f is the focal length and d is the disparity. However, I am not told any extrinsic other than the camera is 1.5m up from the floor. The disparity is already an inverse disparity so I guess z=f*d? Also, what do I do with the other parameters in my K matrix (596, 149)? Is there any implementation in a library like OpenCV to recover the scale-aware 3D coordinates?</p>