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Hawk-Eye is a computer system used in cricket, tennis and other sports to track the path of the ball. It was developed by engineers at Roke Manor Research Limited in 2001; the patent being held by Paul Hawkins and David Sherry. Later, the technology was spun off into a separate company, Hawk-Eye Innovations Ltd., as a joint venture with television production company Sunset + Vine.

Applications in sport


The technology was first used by Channel 4 during a Test match between England and Pakistan at Lord's Cricket Ground, on 21 April 2001. Since then it has been an indispensable tool for commentators. However, the system is not used by the umpires to adjudicate on LBW decisions in Test cricket or One Day International cricket. It is used primarily by the majority of television networks to track the trajectory of balls in flight.

Its major use in cricket is in analysing leg before wicket decisions, where the likely path of the ball can be projected forward, through the batsman's legs, to see if it would have hit the wicket. Currently this information is only visible to television viewers, although it may be adopted in the future by the third umpire, who currently sees only conventional slow motion replays. Consultation of the third umpire on leg before wicket decisions is not currently sanctioned in international cricket.

Due to its realtime coverage of bowling speed, the systems are also used to show patterns of bowling in a bowler's behaviour. At the end of an over, all six deliveries are often shown simultaneously to show a bowler's variations, such as slower deliveries, bouncers and leg-cutters. A complete record of a bowler can also be shown over the course of a match.

Batsmen also benefit from the analysis of Hawk-Eye, as a record can be brought up of the deliveries batsmen scored from. These are often shown as a 2-D silhouetted figure of a batter and colour-coded dots of the balls faced by the batsman.

Hawk-Eye has a couple of other useful features. Because of the six cameras tracking the ball, Hawk-Eye picks up the exact spot where the ball pitches. Hawk-Eye also measures the speed of the ball from the bowler's hand, so it will tell you exactly how much time the batsman has to react to a ball.

The man who invented Hawk-Eye, Dr Paul Hawkins, is a former Buckinghamshire player.


In the autumn of 2005 Hawk-Eye was tested by the International Tennis Federation (ITF) in New York City and was passed for professional use. Hawk-Eye reported that the New York tests involved 80 shots being measured by the ITF's high speed camera, a device similar to MacCAM. These tests have lately been questioned as a single high speed camera would have up to an inch long 'blind spot' and thus cannot measure to mm-level accuracy. Video based systems are also sensitive to heat and other environmental conditions and a single-day test could not reveal such issues. The Hawk-Eye system has since proved to produce erroneous results at several tournaments, such as in Dubai or at the Australian Open.. During an early test of the system during an exhibition tennis tournament in Australia (seen on local TV), there was an instance when the tennis ball was shown as "Out", but the accompanying word was "In". This was explained to be an error in the way the tennis ball was shown on the graphical display as a circle, rather than as an ellipse. This was immediately corrected.

Hawk-Eye has been used in television coverage of several major tennis tournaments, including Wimbledon, the Stella Artois at Queens, the Australian Open, the Davis Cup and the Tennis Masters Cup. The US Open Tennis Championship announced they would make official use of the technology for the 2006 US where each player receives two challenges per set. It is also used as part of a larger tennis simulation implemented by IBM called PointTracker. Along with Cyclops and Auto-Ref, it is one of several automated line-calling mechanisms used.

In March 2006, at the Nasdaq-100 Open, Hawk-Eye was used officially for the first time at a tennis tour event.

In 2006 the US Open Tennis Championship became the first grand-slam event to use the system during play, allowing players to challenge line calls.

The 2006 Hopman Cup in Perth, Western Australia, was the first elite-level tennis tournament where players were allowed to challenge point-ending line calls, which were then reviewed by the referees using Hawk-Eye technology. It used 10 cameras feeding information about ball position to the computers.

The 2007 Australian Open was the first grand-slam tournament of 2007 to implement Hawk Eye in challenges to line calls, where each tennis player on Rod Laver Arena was allowed 2 incorrect challenges per set and one additional challenge should a tiebreaker be played. In the event of an advantage final set, challenges are reset to 2 for each player every 12 games i.e. 6 all, 12 all. Controversies followed the event as at times Hawk-Eye produced erroneous output.

The 2007 Wimbledon Championships also implemented the Hawk-Eye system as an officiating aid on Centre Court and Court 1, and each tennis player was allowed 3 incorrect challenges per set. If the set produced a tie-breaker, each player was given an additional challenge. Additionally, in the event of a final set (third set in women's or mixed matches, fifth set in men's matches), where there is no tie-break, each player's number of challenges was reset to three if the game score reached 6-6, and again at 12-12. Gabashvili, in his 1st round match against Federer, made the first ever Hawk-Eye challenge on Centre Court. Additionally, during the finals of Federer against Nadal, Nadal challenged a shot which was called out. Hawk-Eye "proved" it otherwise, with the ball just clipping the line. The reversal agitated Federer enough for him to unsuccessfully request that the umpire turn off the Hawk-Eye technology for the remainder of the match.

The Hawk-Eye technology was used in the 2007 Dubai Tennis Championships. Defending champion Rafael Nadal accused the system of incorrectly calling an out ball following his exit. The umpire had called a ball out; when Mikhail Youzhny challenged the decision, Hawk-Eye said otherwise. Youzhny said afterwards that he himself thought the mark may have been wide but then offered that this kind of technology error could easily have been made by linesmen and umpires. Nadal could only shrug, saying that had this system been on clay, the mark would have clearly shown Hawk Eye to be wrong.

The Hawk Eye system was developed as a replay system, originally for TV Broadcast coverage. As such, it cannot call ins and outs live. Currently only the Auto-Ref system can produce live in/out calls as it was developed for instant line calling. Both systems can produce replays.

In 2004 several poor calls occurred at the US Open. In Serena Williams' controversial quarterfinal loss to Jennifer Capriati, several poor calls were contested by Williams. TV replays demonstrated that there were actually several crucial calls that were obviously erroneous. Though the calls themselves were not reversed, the chair umpire Mariana Alves was dismissed from the tournament. These errors prompted talks about line calling assistance especially as the Auto-Ref system was being tested by the U.S. Open at that time and was shown to be very accurate.

The Hawk-eye Innovations website states that the system has an average error of 3.6mm (it does not indicate what the maximum error is). The standard size of a tennis ball is reportedly 65 to 68 mm. This means that there is a 5% error relative to the diameter of the ball. This could throw into doubt the accuracy of such calls as the one mentioned in the Nadal-Federer 2007 Wimbledon final. For the sake of comparison, approximately 5% of the diameter is the fluff on the ball.


At the World Snooker Championship 2007, the BBC used Hawk-Eye in its television coverage to show player views, particularly in the incidents of potential snookers. It has also been used to demonstrate intended shots by players when the actual shot has gone awry.

Further developments

On June 14, 2006, it was announced that the Wisden group had bought Hawk-Eye. The acquisition is intended to strengthen Wisden's presence in cricket, and allow it to enter tennis and other international sports. Hawk-Eye is already working on implementing a system for basketball.

According to Hawk-Eye's website, the system produces much more data than that shown on television. This data could easily be shown on the Internet.

The Football Association has declared the system as "ready for inspection by FIFA", after tests suggested that the results of a goal-line incident could be relayed to the match referee within half-a-second ( IFAB, the governing body for the Laws of the game, insists on goals being signalled immediately e.g. within five seconds).

Use in computer games

The use of the Hawk-Eye brand and simulation has been licensed to Codemasters for use in the video game Brian Lara International Cricket 2005 to make the game appear more like television coverage, and subsequently in Brian Lara International Cricket 2007

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