The International Football Association Board (IFAB) has approved goal-line technology at a meeting held in Zurich yesterday. Both GoalRef and Hawk-Eye, the two systems that reached the second phase of testing, were unanimously approved for use, subject to a final installation test at each stadium.
The technology will first be used at the Fifa Club World Cup in Japan in December and, if successful, at the 2013 Confederations Cup and 2014 World Cup.
Hawk-Eye is an optical recognition technology that uses six cameras focused on each goal to track the ball, while GoalRef, developed by the Fraunhofer Institute for Integrated Circuits, is a radio-based solution that uses a microchip implanted in the ball sensitive to a low magnetic field around the goal. GoalRef is a bit like an invisible curtain which hangs behind the crossbar and the goal-line. As soon as the ball fully passes through this curtain, it is recognised as a goal.
The Hawk-Eye system has already been implemented successfully in tennis and, in a broadcast capacity, cricket. It works by first calculating the centre of the ball within each frame of the camera and then triangulates the information from each calibrated camera to give the ball’s 3D position. This process is then repeated for each frame to give a trajectory of the flight of the ball.
The system is accurate to ±3cm, within Fifa’s requirements, and delivers a decision to the referee within one second. Both Hawk Eye and GoalRef met Fifa’s stipulation that the technology gives an accurate decision during the day and night under floodlights and in all weather conditions.
As an optical system, there is a chance with Hawk-Eye that the cameras’ view be blocked by players in the box, although the system only requires a small percentage of the ball to be visible. However, it does give video evidence of whether the ball crossed the line or not. GoalRef doesn’t have these optical constraints, but it does only give a yes/no decision and requires a modified ball.
The decision to look seriously at implementing goal-line technology was galvanised by Frank Lampard’s ‘goal that never was’ against Germany in the 2010 World Cup. Lampard’s ‘goal’ was clearly seen to cross the line on video replays, but was not given by officials in the match. More recently, Ukraine was denied a goal against England at Euro 2012 that seemed to cross the line upon review of the replays.
The English Premier League has welcomed the decision. A statement read: ‘The Premier League has been a long-term advocate of goal-line technology. We will engage in discussions with both Hawk-Eye and GoalRef in the near future with a view to introducing goal-line technology as soon as is practically possible.’
