Football World Cup 2022: artificial intelligence at the service of offside detection

Despite the generalization of VAR (video assistance), offside remains the main point of contention in football. In France, England or in international competitions, everything is now played out to the millimeter, and the cameras often penalize attackers for a shoe size… In front of the small screen, we discover the reasons for the whistle, but in the stands and on the field, it is often frustrating.

theater of the next Football World Cup at the end of the year, Qatar will inaugurate the technology known as semi-automated » offside detection. The goal: to help referees make faster and more consistent decisions on offside situations. Basically, avoid going through the OB van and wasting several minutes deciding whether there is an offside or not.

A sensor in the ball

Validated by the MIT Sports Labthe TRACK team from the University of Victoria and a research team from the Zurich Polytechnic (ETH), this new technology uses 12 cameras placed under the roof of the stadium to track the ball and each player (up to 29 data points checked 50 times per second), which determines their exact position on the pitch. The 29 data points checked include the extremities (head, feet, hands…) and the relevant limbs (arms, legs) for the analysis of offside situations.

To go even further, the Fifa announces that the Al Rihla, the official ball Adidas, will be equipped with a sensor unit of inertial measurement (IMU). This sensor, placed in the center of the ball, sends data to the viewing room 500 times per second, allowing very precise detection of the exact moment the ball is played. Since it must be remembered, the offside is defined from the departure of the ball, and therefore from the gesture of the passer.

A human validation

By combining data from the ball and the players, and using artificial intelligence, the new technology automatically sends an offside alert to the video referees each time the ball is received by an attacker who was in offside position when the ball was played by his teammate.

Before informing the referee on the field, the video referees validate the proposed decision by manually checking the timing of the pass which will have been determined automatically as well as the offside line which will also have been automatically generated. This process only takes a few seconds, allowing for quicker and more accurate decisions on offside situations.

Once the decision has been confirmed by the video referees and the referee on the pitch, the data used to make the decision is translated into a 3D animation detailing precisely the position of the players’ limbs at the time the ball was played. This 3d animatedshown from the best possible angle and similar to what is already done with the goal line technologywill then be broadcast on the stadium’s giant screens and made available to television channels.

Football: towards computer-assisted arbitration

From November 30, Fifa is taking advantage of the Arab Cup in Qatar to test semi-automated offside refereeing. About ten cameras are dedicated to movements players, and application decides whether the player is offside or not when his teammate passes. A technology that could be generalized to all championships.

Posted on November 30, 2021 by Fabrice Auclert

Every weekend, it is a source of controversy and injustice on all football grounds in the world. The offside rule, already complex, has become more and more complicated to arbitrate, and now everything is down to the centimeter! And as there are big sporting, but also economic stakes behind each decision, Fifa and the various international federations use the latest technologies to limit errors as much as possible.

Certainly, video arbitration has been generalized for several years, but it still does not prevent errors of appreciation since it is theeye human, behind his screens who determines whether there is offside or not, and who transmits the information to the referees on the field.

A life-size test one year from the World Cup

In an attempt to find the best possible solution, Fifa will test a semi-automated systemdesigned in particular with engineers from the Massachusetts Institute of Technology (MIT) but also from the universities of Melbourne and Zurich. The full-scale test takes place from today during the Arab Cup, which takes place in Qatar. A competition which was not chosen by chance since it is a real rehearsal before the 2022 World Cup which will take place in a year, at the same period, in the same stadiums.

This technology is based on 10 to 12 cameras placed under the roof of the stadium, and it has already been tested in Europe in Germany, Spain and England. These cameras track 29 data points per player, and 50 times per second. They make it possible to square the field, and to detect in real time the departure of the ball in relation to the positions of the attackers. A 3D grid since the rules stipulate that ” a player is in an offside position if any part of his head, trunk or legs is in the opponents’ half of the pitch (not including the halfway line) and closer to the opponents’ goal line than the ball and the penultimate opponent”.

Data transmitted almost in real time

Previously, we were content to look at the feet of the player, and now we have to take into account his head or his torso, and the human eye is no longer enough to better appreciate the position of the attacker. In fact, the cameras make it possible to draw lines on the pitch, one for the attacker at the moment of the start of the ball, and the others represent the defenders. It’s a bit the same principle as for a photo finish in a race.Athletics.

According to Fifa, the data collected is transmitted almost in real time to the video assistance cell for arbitration (VAR). There, there is now a referee specially dedicated to offside who, in a few seconds, will give his opinion to the referee of the meeting. The latter will decide whether the player who is flagged offside was part of the action or not.

” Technology is very important and useful both in pre-match preparation and in the decision-making process during matches,” explains Pierluigi Collina, refereeing legend, now head of refereeing at Fifa. ” In an offside situation, the decision is made after analyzing not only the position of the players but also their involvement in the movement. Technology – today or tomorrow – can draw a line but the evaluation of a interference with play or with an opponent remains in the hands of the referee. »

Which means that, unlike the Goal-Line Technology, used to determine if a ball has crossed the goal line, the referee will still have the last word. It remains to be seen whether the two touch referees will still be useful in the years to come…