Hawk Eye

Hawk-Eye is a complex computer system used officially in numerous sports such as tennis, Gaelic football, badminton, hurling, Rugby Union, association football and volleyball, to visually track the trajectory of the ball and display a record of its statistically most likely path as a moving image.

Hawk-Eye was developed in the United Kingdom by Paul Hawkins. The system was originally implemented in 2001 for television purposes in cricket. The system works via six (sometimes seven) high-performance cameras, normally positioned on the underside of the stadium roof, which track the ball from different angles. The video from the six cameras is then triangulated and combined to create a three-dimensional representation of the ball's trajectory. Hawk-Eye is not infallible and accurate to within 5 millimetres (0.19 inch) but generally trusted as an impartial second opinion in sports.

It has been accepted by governing bodies in tennis, cricket and association football as a technological means of adjudication. Hawk-Eye is used for the Challenge System since 2006 in tennis and Umpire Decision Review System in cricket since 2009. The system was rolled out for the 2013-14 Premier League season as a means of goal-line technology. In December 2014 the clubs of the first division of Bundesliga decided to adopt this system for the 2015-16 season.

All Hawk-Eye systems are based on the principles of triangulation using the visual images and timing data provided by a number of high-speed video cameras located at different locations and angles around the area of play. For tennis there are ten cameras. The system rapidly processes the video feeds by a high-speed camera and ball tracker. A data store contains a predefined model of the playing area and includes data on the rules of the game.

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