Goal-line technology fitted at Maracana
Brazil's Maracana stadium has been fitted with goal-line technology equipment ahead of the start of the Confederations Cup.
The tournament, which kicks off on Friday, will be the first international competition to make use of the technology after it was tested during the 2012 Club World Cup in Japan.
Bjoern Linder, chairman of GoalControl, the company behind the system chosen by FIFA, says the process will be efficient and result in a quick, accurate decision.
"The whole system uses 14 cameras that are installed on the catwalk," he explained.
"We have seven cameras per goal and computers are connected to those cameras. The computers are catching the images - around 500 pictures per second - and we get by triangulation the position of the ball in real time, and once the computer precepts the ball has crossed the goal line it gives a signal to the referees' watch.
"So all the referees on the field will see the signal, it vibrates and gives an optical signal 'goal' and he knows a goal has occurred."
The English Premier League will become the first domestic competition to use goal-line technology from the start of next season.