Hawk-Eye's system uses seven cameras to track the movement of the ball and sends a signal -- within a second -- to watches worn by match officials when a goal is scored.
Thompson turned around in time to watch it fly toward a row of defenseless photographers sitting on the baseline, and then raised his hand to signal it was his team's ball since he hadn't touched it last.
The image wasn't perfect (expected for a first attempt), as at certain times the signal would wig out and at others -- when the ball moved fast enough -- it got fuzzy.