Goal line technology made its debut in international football last weekend at the Confederations Cup in Brazil. FIFA, the sport’s governing body bowed to international pressure after a missed call in the 2010 World Cup.
Video replays of a match between England and Germany clearly showed England’s Frank Lampard scored a goal against Germany that was denied because neither the referee nor linesman saw the ball cross the goal line after it bounded down off the crossbar and out onto the field of play.
Bjorn Linder’s job is to make sure officiating mistakes like that never happen again. He is the chairman of GoalControl, the German-based company awarded the contract for this year’s Confederations Cup.
His team has been in Brazil for weeks prior to the upcoming matches as part of the FIFA certification process.
“The whole system uses 14 cameras that are installed on the catwalk,” Linder said. “We have seven cameras per goal and computers that are connected to those cameras. The computers are catching images, around 500 pictures per second.”
Computers track the trajectory of the ball in real time and reconstruct the play.
Once the computer perceives the ball has crossed the goal line, it gives a signal to the referee’s watch,” Linder said. All the referees on the field receive the signal. It vibrates and gives an optical signal ‘goal’ and he knows a goal has occurred.
GoalControl claims an accuracy of plus-or-minus 5 millimeters, well under FIFA’s minimum requirement of plus or minus 3 centimeters.
As goal-line technology becomes an integral part of the sport, it is important to remember the referee, and not the computer, makes the final call.