title: get pose from orbslam
body: <p>Hi I need use orbslam to get the pose of camera.
  I know I should use things like  <code>mpCurrentKeyFrame-&gt;GetPose()</code> to get the pose. I saw the source code the "GetPose()" function will return "Tcw". What's the meaning of Tcw here? 
  If I extract "roll pitch yaw " and "x,y,z" from that Tcw, then the "roll pitch yaw" are the camera Euler angles and the "x,y,z" are the camera's position? 
  I did it like that way, I use the <code>mpCurrentKeyFrame-&gt;GetPose()</code> to get the first several keyframes' pose. It returns me the following things for the first keyframe</p>
  
  <p><code>[0.99992567, 0.01199016, 0.0022002477, 0.00021382024;
        -0.011967794, 0.99987924, -0.0099111488, -0.026224624;
    -0.0023188184, 0.0098840808, 0.99994844, -0.0081501938;
    0, 0, 0, 1]</code> </p>
  
  <p>If my understanding is right, [0.00021382024,-0.026224624,-0.0081501938] should be the [x,y,z]. What's the unit of these number?　Is it "meter" or others?
    Then I extract roll pitch yaw from rotation matrix, using equation <a href="http://planning.cs.uiuc.edu/node103.html" rel="nofollow noreferrer">here</a>
  What's the unit of the Euler angles?</p>
  
  <p>Thanks for your answer!!  </p>