Hawk-Eye is a
complex computer system employed formally in several sports such as cricket,
tennis, Gaelic football, hurling and association football, to visually follow
the trajectory of the ball and display a record of its most statistically probable
path as a moving image.
Hawk-Eye was built
in the United Kingdom by Dr Paul Hawkins. The system was initially implemented
in 2001 for television uses in cricket. The system works via six (sometimes
seven) high-performance cameras, usually placed 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 generate a three-dimensional representation
of the trajectory of the ball. Hawk-Eye is not perfect and is accurate to
within 5 millimeters (0.19 inch) but is normally trusted as an neutral second
opinion in sports.