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Every four years, the FIFA World Cup reminds us of what makes the tournament historic: great rivals face off; new stars emerge; and moments become unforgettable.

This World Cup will make history for an additional reason. It's the first time that FIFA -- the world's soccer, or football, governing body -- has permitted the use of technology to automatically detect when a ball crosses the goal line. In a tournament where every goal can mean the advancement of a team, and its nation, the fact that a ball actually crossed the goal line takes on momentous importance.

But reaching this certainty efficiently, quickly, and accurately takes an advanced level of technology, which FIFA found in German company GoalControl.

FIFA announced last year that GoalControl passed its probationary period when it accurately detected the 68 goals scored during the FIFA Confederations Cup in Brazil 2013. FIFA had accepted bids from a total of four goal-line technology companies and selected GoalControl. For the tournament, GoalControl's system, called "4D," used 14 cameras -- seven aimed at each goal -- to measure with absolute precision "if the ball crossed the goal line completely," FIFA wrote.

GoalControl

Rolf Dittrich, a GoalControl spokesperson, explained to CNET by email that the criteria that FIFA and the International Football Association Board (IFAB) used to make its selection included whether the technology could instantly determine if a ball "had" or "had not" completely crossed the goal line, whether it was completely accurate in this matter, and if the technology did not interfere in the game.

For this last criterion, FIFA determined that only the referees should receive a notification if the ball entered the goal -- and if there was no goal, the game would continue without interruption.

With GoalControl's technology, when the ball crosses the goal line, the referees receive -- in the form of a vibration and a message to a wristwatch -- a notification of the goal. "It's important to mention that the referees displayed a high level of satisfaction," FIFA added.

The IFAB has since at least 2007 considered the use of goal-line technology. Other companies it looked at for the Premier League included Hawk-Eye and Goalref. Dittrich said that, like other companies in this industry, GoalControl participated in a competitive process before its selection by FIFA.

When compared with the competition, however, GoalControl's technology won out because of its flexibility and functionality with any goal -- it will detect any type of ball, and no modifications have to be made to the pitch, Dittrich explained.

In addition, he added, the camera's sensors detect a ball's movement to within at least 5 millimeters.

GoalControl

To reach that precision, the images captured by the cameras get sent to a powerful computer that recognizes the ball's movement but ignores the motions of players, referees, and other objects, he said. Mirrored-image cameras with sensors placed on catwalks around the stadium recognize the dimensions of the ball -- its measurements and 3D position -- and ensure the precise detection within millimeters when the ball crosses the goal line.

Dittrich didn't detail the technology used to notify game officials, but said they used proprietary software and secure cryptography to transmit the data. He also didn't specify what type of camera or camera lens used. He added that the officials don't get smartwatches, but that the watches used an integrated circuit technology developed by Fraunhofer-Institute, a German organization. At the moment, the watches only indicate a goal with the word "goal." However, in the future, the company plans to add the time and a timer, he explained.

Dittrich said that while this World Cup promises to have connected stadiums to encourage the use of individual technology, the transmission of data shouldn't interfere with the notification signal to the referees. "All of those influences have been eliminated," he said.

Now that they've proven to FIFA that their technology works, the engineers at GoalControl are preparing themselves for their worldwide debut.

"We've felt like part of the FIFA family from the very beginning," Dittrich said. "GoalControl has been seen not only as a vendor, but as an integral and valued partner. This motivate you and makes it very fun."