For a closer look at how the Hawk-Eye works, launch the photo gallery by clicking 'View Photos' at left.
Its accuracy may be based on a complex computer-generated algorithm, but the Hawk-Eye Tennis Officiating System is ratcheting up the human drama at this year's U.S. Open. Rather than simply relying on officials to make line calls, the entire crowd now acts as referee, hollering "Challenge!" after controversial judgements. If the player chooses to consult the replay (each player is allowed two challenges per set), an animated image of the ball hitting the court zooms into focus on giant screens around the stadium. The effect is so entertaining that tennis officials have actually asked the Hawk-Eye technicians to delay showing instant replays for a few extra seconds to allow suspense and excitement to build.
Developed by English artificial-intelligence expert and entrepreneur Paul Hawkins, the new instant-replay system brings an unprecedented level of accuracy to a game in which the players are bigger, stronger, fitter and quicker, hitting the ball faster than ever and making line calls almost impossible for humans to make. But this is where the Hawk-Eye excels. A series of high-speed cameras surrounds the court and tracks the trajectory of the ball using a system Hawkins first developed for the game closest to his heart, cricket.
"It was an easy fit for cricket, but I always knew this technology was perfect for tennis," says the soft-spoken Brit. Before it was adopted for use at this year's Open, the International Tennis Federation exhaustively tested the Hawk-Eye's ball-tracking capabilities in the lab and at tournaments. Over the course of many rigorous trials, the Hawk-Eye technology was honed to make definitive calls in less than three seconds with zero errors.
At the early test tournaments, most players were incredulous, but competitors like top American James Blake quickly warmed to Hawk-Eye's speed and unfailing accuracy. "With instant replay, we can take advantage of the technology and eliminate human error," Blake said. "And having just a few challenges will make it both fun and dramatic for the fans at the same time."