The new 'Semi-Automated Offside Technology' launches tonight in Champions League group stage

The new Semi-Automated Offside Technology (SAOT) will be used in this season's Champions League group stage. Here is a brief video explaining the process, but you can read more details below.

Last month, UEFA confirmed that it will introduce the brand new technology in this season's UEFA Champions League group stage in a bid to 'enhance the flow of the game and the consistency of decisions'.

Semi-Automated Offside Technology enables video assistant referee (VAR) teams to determine offside situations quickly and more accurately. So how does it work?

A total of 10 dedicated tracking cameras mounted underneath the roof of each stadium will track the ball, and 29 points on the body of each individual player 50 times per second, calculating their exact position on the pitch.

The 29 points include all limbs and extremities that are relevant for offside calls, allowing the team in the video operation room to know the exact position of a player at any given moment.

All of this data is processed in real time by AI, which triggers an alert to VAR when an offside has been detected.

The idea is that this technology will reduce the amount of time it takes to get the tightest of offside calls right. It should be faster and more accurate.

FIFA, meanwhile, will use a slightly different at this winter's World Cup in Qatar.

A sensor in the centre of the Adidas 'Al Rihla' ball sends inertial data 500 times per second, allowing a more precise detection of the kick point compared to conventional broadcasts and optical tracking. These are limited to 50 frames per second.

UEFA will have no sensor inside their Champions League ball or on the players, but AI should make up for it.

On top of this, for improved communication to the fans after the offside decision has been confirmed by the referee, a replay animation is also created and shown in the stadium and on TV.

This replay animation is created using the exact same limb tracking data and kick point information used by the video match officials for the decision.

Live trials took place in February at the Club World Cup – a tournament Chelsea participated in after winning the Champions League – and SAOT was officially used for the first time during the UEFA Super Cup match between Real Madrid and Eintracht Frankfurt in August.

This winter's World Cup in Qatar will also use Semi-Automated Offside Technology and if all goes to plan, it's said the Premier League could introduce SOAT in 2023/24.

Legendary former referee Pierluigi Collina, who is the chairman of the FIFA Referees Committee, is convinced the technology will be a success.

“VAR has already had a very positive impact on football and we can see that the number of major mistakes has already been dramatically reduced," he told FIFA's website.

"We expect that semi-automated offside technology can take us a step further. We are aware that sometimes the process to check a possible offside takes too long, especially when the offside incident is very tight.

"This is where semi-automated offside technology comes in – to offer faster and more accurate decisions.”

He added: “The testing has been a major success and we are very confident that, in Qatar, we will have a very valuable support tool to help referees and assistant referees make the best and most correct decision on the field of play.

"I know that someone called it ‘robot offside’; it’s not. The referees and the assistant referees are still responsible for the decision on the field of play.”

The guys over at Tifo Football have also explained Semi-Automated Offside Technology on their YouTube channel with a neat breakdown.

Thoughts on the technology? Let us know in the comments.