Goal line technology - what is it? How does it work?
Football fans around the world have been debating the use of goal line technology ever since England won the World Cup back in 1066 (I think it was?!). THAT goal against zee Germans sparked debate that has continued to rear its head each and every time a goal is disallowed or awarded when it can be proven via video replay to have been an error in officiating.
You have to feel sorry for the referees. They only have a split second to judge whether a spherical object has fully crossed a white painted line in a field and have 22 players on the park - plus those watching from the side (team and fans alike) - all ready to lynch them, whatever their decision may be.
Goal line technology would remove the errors and make referees better equipped to deal with the baying mob - or so we hope. So what is goal line technology and how does it work? Goal line technology refer to systems that analyse the flight of a ball to determine whether or not it completely crossed the goal line during a football match. Football is MASSIVE business nowadays, with millions upon millions of pounds spent on the running of the teams. The prize money for league positions is £755,000 per place and doesn’t include television rights, payments and prize money for cup competitions; nor does it include ticket and merchandise sales but you get to see just how financially important it is that the major decisions in football (goals are key) are crucial to such a high value business.
Not so long ago I wrote a blog about tennis and Hawk-eye. If you read that you will get an idea of how triangulation works. For those who didn’t read it then here is a basic summary:
To track the flight of a ball (or even for your GPS to work on your smart phone), a method of triangulation is used. Place a number of cameras (3 is the minimum number - tri-angulation) into an arena. Naturally, the more cameras the better because they become more precise and accurate. Working in synch, these camera images are put through a processor. The result is the location of the object which is placed into a map or plot of the area in which it is situated.
With tennis, the Hawk-eye system literally predicts the flight of the ball and uses this prediction to place a ball either in or out. With your GPS it’s used to show you where you are on a map (GPS uses satellites, transmitters and receivers) and is accurate to approximately 10 meters for most consumer GPS devices.
To find out more about GPS etc visit: http://www.pocketgpsworld.com/howgpsworks.php Back to football!
http://www.premierleague.com The Premier League (in England) opted to hand the contract for goal line technology to perhaps the best known company in the UK to provide such a service. Hawk-eye (developed by Dr Paul Hawkins originally for cricket broadcasting - and used to show whether a ball bowled would have hit the stumps) has been around for a pretty long time.
Those cricket fans out there will remember seeing a graphical flight of a ball used in commentary on television prior to its use as a review system for the umpires themselves during game play.
The system for football works in exactly the same way as the system for cricket and tennis. A number of cameras are used to plot the flight of the object (ball) and placed into a 3 dimensional map of the environment.
For football, seven cameras are placed at either end of the football pitch and all trained on the goal area alone. These seven cameras will record the ball when it comes into their view. As they track the object, the data is sent through to a central computer which uses a minimum of three cameras to precisely locate the ball and place it into its 3D environment. The computer program is effectively watching for the entire ball to cross a line (a parameter in the system). IF Hawk-eye determines the ball has crossed the line it will send a signal to a device worn on the referees wrist, who will in turn award a goal.
Factors such as player’s bodies or fog obscuring the ball from the camera will not be a problem using Hawk-eyes system for a couple of reasons: The placement and number of cameras mean there will always be a view of the ball to locate it and therefore “predict” its path (Hawk-eye uses the flight of the ball to predict it’s trajectory rather than review it after an incident).The cameras are of such high quality that fog will not obscure their ability to “see” the target.. All this takes place within one second and therefore delays in play are not likely to become an issue! Hawk-eye (in football) is accurate to 3cm. While this is extremely accurate, it has been argued that more than an inch is too great a margin when the object is only 9 inches across (a professional football is between 27 and 28 inches in circumference). As with most broadcast sports that use a Hawk-eye system the graphical images are available for television usage.There is currently a discussion to allow them to also be used on the large screens within the stadia itself but at present this has not been given the go ahead!
http://www.hawkeyeinnovations.co.uk It is worth stating at this point that while The Premier League has adopted this system, UEFA is currently still against the use of any goal line system. So any club that has this technology within its stadia will have to turn it off for an UEFA based competition.
FIFA on the other hand has given the green light for goal line technology to be used in its sanctioned competitions and is considering using a form of system in the 2014 World Cup. Other versions of goal line technology that didn’t get the thumbs up treatment from The Premier League hierarchy include:
http://www.cairos.com/ Cairos Technologies AG Cairos Technologies AG developed a system which incorporated a magnetic field in the penalty area with a sensor that is suspended within the ball itself.
To generate the magnetic field they would place thin cables with an electrical current running through under the turf in the penalty box and behind the goal line to create a grid. The sensor within the ball measures the magnetic grid as it moves across the area and relays data to a computer which in turn determines if the ball has crossed the line or not.
If the system believes a goal to have been scored, a signal is sent to the referees watch within one second of the incident occurring. To make this system workable, Adidas designed a football that could contain a sensor suspended within that would remain intact even when the ball is struck with great force.
Goalminder Perhaps the cheapest of all the options, Goalminder places high speed cameras (taking 2000 frames per second) onto the goal posts and the cross bar. These images are then used to deliver visual evidence to the referee to enable him (or her) to make a decision – in less than 5 seconds. This system has been ruled as the simplest but most time consuming method. It is the fact that it could take a period of time for a human to analyse the footage to determine an outcome that has caused it to be the least successful of the options in terms of it's bid for use.
Goalref http://www.alexandra.dk/uk/projects/pages/goalref-intelligent-football.aspx A second technology involving electronic circuits and the ball directly. GoalRef uses a passive electronic circuit which is embedded in the ball and a low-frequency magnetic field around the goal itself. If the electric field that is generated is changed at all it is detected by coils which are imbedded in the goal frame, that in turn determine whether the ball crosses the line. This is extremely technical as the electric field is very minimal, yet the circuit in the ball is enough to trigger the system WHEN the ball fully crosses the (electric) field itself.
Picture a sheet of fog across the goal line. If the full dimension of the ball were to pass through this fog, the system would detect it and the referee would receive a signal on their wrist watch device. So which system is best? Which will be “the” future? The million dollar question! The answer is very much dependant on which organisation you wish to know about, which tournaments and which countries! The Premier League has given the go ahead for Hawk-eye to be used in the 2013/14 Premier league season after a closely run tussle between them and GoalRef. Last year saw FIFA award both Hawk-eye and GoalRef the go ahead to be used in the 2012 FIFA World Club Cup in Japan. FIFA have also identified the Cairos Technologies AG version as a viable option and are now weighing up the systems for successful implementation at the World Cup in Brazil in 2014. This decision is (at the point of writing the article) awaiting announcement.
I hope you have found this of some interest! Please leave your comments on my Twitter: www. twitter.com/BrynLucas or Facebook: www.facebook.com/brynlucasfanpage Sources: Wikipedia: http://en.wikipedia.org/wiki/Goal-line_technology Goal Control: http://goalcontrol.de/gc4d.html Hawk-eye: http://www.hawkeyeinnovations.co.uk/ Cairos Technologies AG: http://www.cairos.com/ GoalRef technology: http://www.alexandra.dk/uk/projects/pages/goalref-intelligent-football.aspx UEFA: http://www.uefa.com/ FIFA: http://www.fifa.com/
