Hawk-Eye inventor still to convince it's a good call for tennis

At a tennis club in Hampshire next week a trial is scheduled to take place which may change forever how matches are umpired. Paul Hawkins and his team hope to persuade the International Tennis Federation to use their Hawk-Eye technology to resolve line-call disputes.

At present it is an analytical tool which is only used by the media - the BBC at Wimbledon, and also at all other Grand Slam events. It has also been used at a Davis Cup tie, the Masters event and at Queen's. The organisers of the Australian Open, in particular, are enthusiastic about increasing its use, and there has been vocal support from former players such as John McEnroe who, of course, knows a thing or two about disputed line-calls.

Hawkins has been working hard to persuade a reluctant ITF and explain how Hawk-Eye, which almost instantaneously generates a 3D image of where the ball lands, works. "It aims to resolve controversial decisions, so in tennis that is often line-calls," he says. "Umpires already have Cyclops, so technology is being used to help, not replace, them. You do have an obligation to make sure it's the players' ability that decides a match and not the mistakes of an umpire."

But that is one reason why the authorities are reluctant to agree - they feel the technology will undermine the role of the umpire which, at best, is under constant questioning. Hawkins, who first introduced Hawk-Eye to review controversial lbw decisions in cricket, disagrees.

"I think there is a strong body of opinion that Hawk-Eye should be used to help umpires make official decisions," he says. "We did an event last November where the umpires used it if a player disputed a bad call, but it was a non-ATP Tour event. And often Hawk-Eye shows the umpire is correct so, if anything, we give the umpires credibility."

Hawk-Eye is a simple system. At Wimbledon - which agreed for it to be installed last year, but only to aid the media - it is deployed on Centre and No 1 Courts. "There are five high-speed cameras high up in the roofs which track the ball as it flies through the air," says Hawkins.

"A computer captures the image from each camera and works out where the ball is. By finding the ball in multiple cameras we can find out where the ball is in 3D space - where it is in the real world, if you like. The computer then combines all this information and traces the trajectory of the ball in each rally. This information is then sent to the virtual- reality machine which produces the graphic images you see on the television. So Hawk-Eye is able to show where the ball landed in every point played."

Hawkins adds: "The bounce mark of the ball that Hawk-Eye shows is accurate to 3mm. We also take into account the amount the ball compresses and skids on the court." McEnroe, for example, has suggested that players should have a number of appeals they can make each match to the Hawk-Eye machine.

Nevertheless, the authorities are reluctant, despite the system's speed. Cost is another issue they highlight, saying that if they approve it, the machines will have to be used on every court and in every competition. And that would be expensive. Interestingly, players are said to be more enthusiastic.

In the drama of his defeat to Tim Henman, a comment from Mark Philippoussis was telling. The Australian, who was warned after swearing following a disputed line-call, said it was time that umpires had access to slow-motion video replays at courtside.

Philippoussis went on to say he had received text messages from friends watching back in Melbourne telling him Hawk-Eye had confirmed he was right, the line judge was wrong.

The Australians also believe Hawk-Eye can be used to improve technique, and argue that this is what has happened in cricket, where it has operated for the past four years.

Henman, who also questioned several calls, takes a more traditional view. "Balls are flying around at 130mph and it's a tough job to be a line judge," he says. "Some calls go in your favour, some don't." Hawk-Eye, its inventor argues, would end that uncertainty forever.