Hawk-Eye
Hawk-Eye is a computer vision system used to visually track the trajectory of a ball and display a profile of its statistically most likely path as a moving image. It is used in more than 20 major sports, including baseball, cricket, tennis, badminton, hurling, rugby union, soccer, Gaelic football, American football, and volleyball.
The Sony-owned Hawk-Eye system was developed in the United Kingdom by Paul Hawkins. The system was originally implemented in 2000 for television purposes in cricket. It works via the use of up to ten high-performance cameras, normally positioned on the underside of the stadium roof, which track the ball from different angles. The video from the cameras is then triangulated and combined to create a three-dimensional representation of the ball's trajectory. Although not infallible, Hawk-Eye is advertised to be accurate to within 2.6 mm (100 thou).
Hawk-Eye is increasingly used as an impartial review in sports, having been accepted by governing bodies in tennis, cricket, and association football (soccer) as a means of adjudication. Hawk-Eye has been used for the Challenge System since 2006 in tennis and Decision Review System in cricket since 2009. The system is also used to determine whether the ball has crossed the goal line in football as a means of goal-line technology, implemented in the 2013–14 Premier League season and now present at many domestic leagues and international competitions.