A small incident occurred during the group stage match of the World Cup between Sweden and Tunisia: in the 84th minute, Swedish player Svahnberg scored a goal during a set-piece attack, but it was disallowed for offside.

Video replay clearly showed that at the moment the free kick was taken, Svahnberg was indeed in an offside position. However, shortly after, the referee, after consulting with the Video Assistant Referee (VAR) team, overturned the decision and signaled the goal as valid.

The decisive "evidence" for this decision was the official match ball of this World Cup—the "Triple Wave."

On June 14th, local time, Swedish player Isaac (left) scored a goal during the match. Photo by Martin Sabala (Xinhua News Agency)

Inside the "Triple Wave" ball, there is a tiny motion sensor chip that can collect data on the ball’s movement trajectory, speed, spin, and directional changes at a rate of 500 times per second, transmitting this data in real-time to the VAR system.

It was this chip that captured an imperceptibly small contact moment: after the free kick was taken, the Swedish forward Isaac at the front post lightly brushed the ball with his foot, and at that moment Svahnberg was no longer in an offside position, making the goal valid.

In the 2022 Qatar World Cup, FIFA embedded sensors into the match balls. The data transmitted by the sensors, combined with the real-time tracking of the ball’s position and up to 29 body data points of each player by 12 high-speed cameras around the field at 50 times per second, formed the core framework of the semi-automatic offside detection system.

In the opening match of that World Cup, just three minutes into the game, Ecuador’s Valencia scored a header that was disallowed by the semi-automatic offside system, becoming the first goal in World Cup history to be overturned with the system’s intervention.

Photo of the opening match of the 2022 Qatar World Cup. Photo by Zheng Huansong (Xinhua News Agency)

This World Cup, the semi-automatic offside detection system has been further upgraded. Each stadium is equipped with 16 optical tracking cameras, capable of capturing over 150 million tracking data points per game. FIFA’s Director of Innovation Holzmueller explained that this data allows FIFA to recreate the entire match in 3D and provide footage to VAR—especially useful for determining whether an offside player interfered with play.

Since there is a chip, it needs to be charged. Data shows that each "Triple Wave" match ball must be placed on a dedicated charging dock before the game. Fully charged in about 90 minutes, it can then operate continuously for approximately 6 hours.

FIFA President Infantino once stated that the deep integration of artificial intelligence and data analysis technology is improving the transparency and accuracy of modern football officiating.