MYOPIC HAWKEYE?

The Hawk-Eye line-calling system used at Wimbledon may not be quite as accurate as people think.

At Wimbledon, Hawk-Eye has 10 cameras positioned around the courts. The technology reconstructs the ball's most likely path by combining its trajectory using images from the cameras. Hawk-Eye does not reproduce what actually happened, but what was statistically most likely to have happened.

The technology has divided players. While Roger Federer dismissed Hawk-Eye as "nonsense'' after its introduction at the Australian Open last year, Andy Roddick is an avowed fan.

Former Wimbledon champion Lindsay Davenport said she has confidence in Hawk-Eye and believes it is accurate.

During last year's Wimbledon final, a series of Hawk-Eye challenges from Rafael Nadal infuriated Federer. The Swiss thought he had won the third set when a line call challenge from Nadal reversed the decision.

On Hawk-Eye's Web site, an analysis of the disputed call states that it was "likely'' that the ball was in by 1 millimeter (0.04 inches). Federer ultimately won the championship, but not before complaining to the chair umpire that the electronic system was "killing'' him.

Paul Hawkins, managing director of Hawk-Eye technology, says the line-calling system has gone through more than 1,000 tests. "We've gotten every single one of the tests correct,'' he said.

Hawkins said that Hawk-Eye's margin of error averaged about 3.6 millimeters (0.14 inches) and that the system was around 99.9 percent accurate.

Aside from Wimbledon, Hawk-Eye is also used at the U.S. Open and the Australian Open. The system is also used for line calls in cricket.