Cameras, smart balls, 3D avatars: AI referees are reshaping the World Cup

The 2026 FIFA World Cup in North and Central America, now in its group stage, is being hailed as a new chapter in refereeing technology, with AI and data systems combining to push officiating errors close to zero. On top of the semi-automated offside technology (SAOT) that debuted at the 2022 Qatar World Cup, this tournament has added dedicated cameras, smart balls and 3D player avatars to the mix.

The technology has been particularly effective on offside calls. Differences of as little as 1 millimeter between an attacker and a defender are now being detected, producing a string of moments where a goal celebration is cut short by an offside ruling.

The refereeing system at this World Cup is built on a fusion of AI-based optical tracking and sensor data.

Dedicated cameras are mounted densely across stadium roofs, tracking every movement of every player on the pitch. They capture not just position but 29 individual joint points per player — head, feet, shoulders and more — recording three-dimensional data 50 times per second.

The ball itself has also evolved. The official match ball contains an inertial measurement unit (IMU) sensor that reads vibration and acceleration 500 times per second the moment a player's foot makes contact, transmitting that data to the video review room. AI then combines the precise moment of the kick with player position data in real time to calculate whether an offside line has been crossed.

Throughout each match, an identical digital twin of the stadium runs on computer servers, tracking player movements in fine detail under any circumstances.

The data does not stop at offside decisions. It is also processed into performance metrics — top speed, sprint counts, range of movement — that feed into tactical analysis and real-time broadcast graphics.

Per-player 3D avatars have also captured fans' attention.

FIFA digitally scanned the body shapes of participating players to build precise 3D models. The existing VAR display has been upgraded to show in three dimensions exactly which body part — an attacker's elbow or toe, for instance — crossed the line.

Yet even with all this technology, there remains a domain that belongs to human judgment.

Offside rules can require reading the context of a situation — whether an attacker blocked a defender's line of sight, or directly interfered with play. Even when AI processes the scene, the final call ultimately rests with the referee.

Cybersecurity and infrastructure stability are also critical concerns. Dozens of cameras and in-ball sensors exchange vast volumes of data in real time over wireless networks. A sudden surge in traffic causing network delays, or even a minor synchronization error, could bring the entire advanced officiating system to a halt.