Perched high above Qizhong Stadium’s Center Court are two inconspicuous rooms that house the Hawk-Eye system, providing the ultimate in conflict resolution.
Since its introduction in 2005 for tennis, Hawk-Eye has practically ended the era of epic player and umpire confrontations over close line calls. While a few till try, it’s nevertheless hard to argue with a machine that projects a binary “in” or “out” with a virtual reality reconstruction of the flight and impact point of the ball.
Many years ago a more rudimentary system was used and the great John McEnroe was getting beeped and in a flash he said, “I’m not paranoid but that machine knows who I am.”
“I think that it actually improves fan engagement,” Andrew Simpson, Hawk-Eye Operations Manager for Asia says. “The whole stadium is involved in the build up to the call rather than just a quick call made by an umpire.”
Simpson arrived in Shanghai with his team of eleven operators five days before the start of play to set up, map and calibrate the 30 cameras located on the three stadium courts, a process that involves hitting actual balls to measure the ball marks to then compare with the Hawk-Eye results.
During matches, at least five cameras track the flight of the ball on each side of the court, each taking 75 high-resolution images per second. Sophisticated software then uses an algorithm that considers factors such as the size of the ball, the width of the line, the flight of the ball, and probable distortion of the ball upon bouncing to visually reconstruct the bounce point. Here in Shanghai, a 4K camera shows the actual ball in flight before phasing into a virtual reality shot.
While there is an average error margin of 2.6-3.6mm, that’s significantly lower than the average of 40mm by line judges and players who are hampered by “human” elements of bias, lapses in concentration, and viewing angle. Some studies show that we’re more accurate at seeing the ball if its trajectory is parallel to the line (ie. side lines and the center service line) than we are when the ball travels directly across the line (ie. service line and baseline).
While other systems utilize cameras which take images of the actual ball bounce points, the advantage of Hawk-Eye is that it also captures information like speed, direction, and trajectory which is invaluable to players and coaches in determining things like how high a serve is bouncing and where players are standing when they make contact with the ball. “We can tell you where each and every serve has landed in Shanghai,” says Simpson. “There are literally thousands of data points”.
After each match, a match analysis document is made available which provides the information to players and coaches, including rally hit points and shot placement. Hawk-Eye is now used in over 80 tournaments around the world. While the French Open notably doesn’t use Hawk-Eye technology to challenge line calls, the camera set-up is still in place to capture statistics.