[an error occurred while processing this directive]
BBC News
watch One-Minute World News
Last Updated: Thursday, 4 August 2005, 10:51 GMT 11:51 UK
Tags 'can improve offside calls'
Gudjohnsen scoring for Chelsea against Arsenal
Chelsea celebrate but this goal was ruled offside
Having footballers wear electronic tags could help improve the accuracy of offside decisions, a student claims.

Computer science student and Manchester United fan Jonathan Dunne researched the issue after being incensed by decisions in a match he was watching.

He reckons tags could track the players and ball to within five centimetres.

"The offside rule is complex and often incorrect decisions can cost a club not only a game, but potentially millions of pounds in lost revenue," he said.

Recent research has suggested the human eye cannot process all the information necessary to implement the rule.

Slowing down the game?

He examined three possible systems: tagging using radio frequency identification (RFID), satellite tracking and video content analysis.

Satellite tracking would send signals from satellites to receivers in players' kit to track them, and video content analysis would use software and high-resolution cameras suspended above the pitch to log their positions.

The referee would receive a real-time signal on a gadget such as an earpiece, so there would be no need to stop play - unless there was an offside offence
Jonathan Dunne

But Mr Dunne said RFID was the most cost-effective and accurate system. It would probably cost a few million pounds to develop the initial software, but expanding it to clubs would be relatively cheap, he said.

Objections to the greater use of technology in football have included the disruption to the flow of play that would be caused by reviewing decisions.

But tracking did not automatically mean the game would be stopped, Mr Dunne said.

"With RFID the referee would receive a real-time signal on a gadget such as an earpiece, so there would be no need to stop play - unless there was an offside offence," he said.

"I wouldn't envisage removing the referee's assistant.

"He could still indicate when a player is offside, but the technology would be able to give a definitive answer."

Visual field

Research by Dr Francisco Belda Maruenda has suggested the human eye is physiologically incapable of processing all the information necessary to apply the offside rule correctly.

Dr Maruenda claimed the referee's assistant needed to keep track of five moving objects in his visual field at the same time.

He is nearer to the opposition goal line than both the ball and the second from last opposing player and
He is interfering with play, or
He is interfering with an opponent, or
He is gaining an advantage by being in that position

These would be: two players in the attacking team, two players of the defending team and the ball.

The offside rule states that at least two opposition players must be between the goal and the attacking player, or at least level with the player, when the ball is passed.

World governing body Fifa recently brought in a new guideline whereby the linesman's flag would be raised only when an offside player actually touched the ball.

But the Football Association said it would not be applying this.

An FA spokesman told BBC Sport: "The law has not changed, just the interpretation of it.

"The offside law in England will be the same as it was last season."

In 2001 the idea was floated of using a Norwegian technology called the Reference Point Sytem, which consisted of a series of infra-red rays at intervals along the touchline.

The FA looked into it but found little interest and it was never tried in competitive matches.

Jonathan Dunne says his research is still at the feasibility stage but he hopes it will be taken on in the form of a pilot.

The work was undertaken during the final year of his MEng in computer science at the School of Electronics and Computer Science at the University of Southampton.

Consumer concern over RFID tags
09 Feb 05 |  Technology
Think you know your offside?
15 Jul 05 |  Football
FA considers goal-line technology
05 Jan 05 |  Football
FA decides against offside change
21 Jul 05 |  Football
New offside rule angers managers
15 Jul 05 |  Gossip & Transfers
Blatter suggests offside change
04 Jan 05 |  Football
Human eye 'cannot spot offside'
17 Dec 04 |  Health

The BBC is not responsible for the content of external internet sites


News Front Page | Africa | Americas | Asia-Pacific | Europe | Middle East | South Asia
UK | Business | Entertainment | Science/Nature | Technology | Health
Have Your Say | In Pictures | Week at a Glance | Country Profiles | In Depth | Programmes
Americas Africa Europe Middle East South Asia Asia Pacific