Or you can check out the video I recorded at youtube.
Try closing one of your eyes and then move you head slowing relative to the screen.
Check if the camera capture at the top-left corner acts like a mirror. Check the flip camera box if needed.
You can fine tune the system by the UIs below the camera view port. See details below.
Red/black rectangles are the head-detection results. Green dots and rectangle is optical-flow tracking. White rectangle is the resulting head position.
screen width and head size is in the unit of size of your hand. Just to let you measure them easily.
head size at distance 2 and head size at distance 3 is the detected head size in pixels. You can set them by placing your head 2 or 3 hands from the camera and click the get button.
from my blog post.