title: How to draw 3D Coordinate Axes with OpenCV for face pose estimation?
body: <p>Suppose I have got the face euler angles (pitch, yaw, roll). How can draw the 3D Coordinate Axes which show the face pose?</p>
  <p>Here is an example from <a href="http://www.morethantechnical.com/2010/03/19/quick-and-easy-head-pose-estimation-with-opencv-w-code/" rel="nofollow noreferrer">here</a>:</p>
  <p><img src="https://i.stack.imgur.com/wKeT4.png" alt="enter image description here" /></p>