FIFA will semi-automate key offside calls at 2022 World Cup

"Limb-tracking technology" and sensors embedded in balls will help officials make crucial offside calls at the 2022 men's World Cup.

FIFA, soccer's global governing body, announced the innovation on Friday, calling it a "semi-automated" video review system that will still be operated by humans, but that will spit out decisions automatically in a few seconds.

The system can be used to overturn or confirm offside calls and non-calls on plays that lead to penalties or goals. Pierluigi Collina, the chairman of FIFA's referees committee, estimated at a media briefing that it will cut the average length of these reviews from roughly 70 seconds to 20-25.

The technology, which has been tested at multiple FIFA tournaments, and which disallowed a goal at this year's Club World Cup, relies on 12 specialized cameras mounted at the top of each stadium. The cameras track 29 points on the body of each player, and collect locational data on each of their limbs and extremities 50 times per second.

Tiny IMU sensors, meanwhile, will be implanted in World Cup balls to transmit their inertial data 500 times per second, via in-stadium antennae, to an off-site replay center. Artificial intelligence will process the data in real time, and replay officials will communicate the AI interpretations to on-field referees.

Those replay officials will check and affirm every decision. They still must make some subjective determinations — Was an attacker interfering with play? Did a defender attempt to play the ball? — as the technology tracks the ball and players in offside positions.

But instead of digitally drawing lines to body parts, and using earlier technology to identify the exact moment at which a ball was kicked, the officials will receive "kick-point" and "offside line" information automatically, and almost immediately.

The system's margin of error, Collina said, is similar to that of goal-line technology: "only a few millimeters."

It was used in February to disallow a goal scored by UAE club Al-Jazira at the Club World Cup. The left knee of the goalscorer, Alameri Zayed, was marginally ahead of the last defender when a cross was delivered.

After decisions are made, the technology automatically generates animated 3-D replays that, according to FIFA officials, will be shown in stadiums and on TV at the next opportunity. These will, FIFA believes, be a significant upgrade from the digitally drawn lines and bland messages currently used on TV broadcasts and in stadiums across most major professional leagues.

Collina said the semi-automated will be "more accurate" than the current system. But he repeatedly stressed the uptick in speed most of all.

"We are aware that sometimes the length of checks and reviews is definitely too long, in particular concerning offside," he acknowledged. "Accuracy and speed don't live together. And we understand that it's difficult to keep waiting quite long before a decision is taken."

The new technology — which was developed in consultation with leading universities in multiple countries, including MIT — will not address that dilemma on non-offside calls. It also will not quell the criticism, which frequently comes from fans and players alike, that the presence of video review, popularly dubbed "VAR," tempers the emotion that greets every goal, because it looms in wait, threatening to find unseen violations and nullify seemingly good goals.

But, four years after VAR's mostly successful introduction to the 2018 World Cup, FIFA officials believe that the semi-automated system will enhance it for all parties at this year's tournament, which begins Nov. 21 in Qatar.

Some domestic leagues and the UEFA Champions League are expected to implement the new system by 2024 as well.