title: Drawing fixed set of grid lines with OpenCV
body: <p>Is it possible to draw user-defined grid lines with defined points at all intersections, against the output of the color detection sample in the OpenCV sample file? Basically, the webcam will need to be detecting human head and shoulders from above you. Then when a person is detected, I need the grid lines to be there so that I am able to know from which outermost grid (left shoulder), to the next outermost grid (right shoulder), in both x and y axis (forehead and back of head). Thereafter, these points have to be sent for operation of mechanical parts like actuator and valves.</p>
  
  <p>I'm an entry level OpenCV user, with just beginner knowledge about working with C++.
  I am currently using OpenCV 2.1 on VS2008.</p>