Hoping to avoid incorrect calls by referees -- and following the 2010 game where England was wrongly denied a clear goal during its match against Germany -- FIFA implemented goal line technology at this year's World Cup. The multi-part system by the German company GoalControl costs approximately $250,000 to install per stadium.
The system uses 14 high-speed cameras to track the ball's position on the field and in the air, working at 500 frames per second. "Outstanding features of the GoalControl-4D system are high accuracy, the real-time processing and high frequency of the pictures as well as the absolute reliability and repeatability," Dirk Broichhausen, managing director of GoalControl, told EE Times back in May.
Cameras are connected to a powerful image processing system that tracks the movement of all objects on the field and filters out the players, officials, and everything else but the ball.
Powerful image processing algorithms identify the ball and its position within each camera's viewpoint and calculate via triangulation its position in the goal mouth to within millimeters. The accuracy specification is better than +/- 1.5 cm. If the triangulated ball passes the goal line, a specially designed smartwatch alerts the referee within one second.
The vibrating smartwatch was designed in collaboration with the Fraunhofer Institute for Integrated Circuits in Erlangen, Germany, and is based on a Texas Instruments watch powered by a chip set from the chip maker. It uses the Fraunhofer group's patented software and protocol. The FIFA-approved device operates in the frequency ranges of 865-870 MHz and 915-930 MHz.
Social media reviews of the system have been mostly positive. It was first used at the France-Honduras game on June 15. Still, the use of smartwatches seems to be overkill. Are smartwatch notifications necessary in an often low-scoring game (with the exception of the semifinal in which Germany kicked the host Brazil out of the competition by a score of 7-1)?