Hawk-Eye System in Cricket
Hawk-eye is the name of a computer system which traces a ball's trajectory, with a claimed accuracy of 5 mm, and sends it to a virtual-reality machine.
Hawk-Eye uses six or more computer-linked television cameras situated around the cricket field of play. The computer reads in the video in real time, and tracks the path of the cricket ball on each camera. These six separate views are then combined together to produce an accurate 3D representation of the path of the ball.
The Hawkeye system was launched in 2001. It was first used in television coverage of sporting events such as Test cricket, and has now reached the stage of being used by officials in tennis to assist in adjudicating close line calls.
The system was first used during a Test match between Pakistan and England at Lord's Cricket Ground, on 21 April 2001, in the TV coverage by Channel 4. Since then it has been an indispensable tool for cricket commentators around the world. It is used primarily by the majority of television networks to track the trajectory of balls in flight, mostly for analyzing leg before wicket decisions. The ball by ball tracking by the Hawk-Eye system also allows the broadcasters to showcase many other features of the game, such as comparing the bowlers' speeds, spin, swing, line and length.
In the case of LBW decisions, Hawk-Eye is able to project the likely path of the ball forward, through the batsman's legs, to see if it would have hit the wicket. In addition to providing information to TV viewers, the technology is also used by the third umpire to adjudicate on LBW decisions that have been referred.
Although Hawkeye is very accurate in measuring the actual path of a ball, when it comes to predicting the future path of the ball, such as in LBW decisions, it is not as clear. If the ball is heading to the pitch, there's no way Hawk-eye can tell if a delivery is going to skid a bit more than normal or hit a crack, bit of grass, or worn patch of the pitch. The predicted path of the ball is based on the average and expected pathway.