The automated counting system for the corner goals is composed of an camera system located above the goal, and a back-lit diffuser panel in the floor of the ramp on the interior (ball corral side) of the goal. Jeff Wetzel has posted a picture of the
overhead camera and the
back-lit panel. The camera system is not a simple break-beam counter. The system was developed by National Instruments, and is designed to recognize and discriminate between individual balls that may enter the goal at the same time. The system is a full computer vision application, and explicitly looks for circular objects passing in front of the back-lit panel. During testing, the system easily handled three balls passing into the goal simultaneously (ie. side-by-side across the full width of the goal), and up to 10 balls entering the goal per second.
Note that the "3-inch incursion buffer" inside the goal is about the same distance as the set-back from the goal opening to the back-lit panel.
-dave