I’m experimenting with tracking a marker using the same technique that Sony uses to track the move. By counting the number of pixels in a blob, you get area. By taking sqrt(Area/PI) you can get the radius (assuming sphericality of blob object). Radius is inversely proportional to distance from the camera, so you calibrate it once and it’s done. The measuring tape ends at 12″ so you can see it’s calibrated in the video. Marker is a ping-pong ball with a modified wide-angle LED keychain inside.
PSEye Ball Tracking
