“It is not a 3-D re-creation; we give the real image,” Simon said. “We see the surface of the court how it is, even if it has moved or just moved.”
This year, the U.S. Open became the first Grand Slam event to use almost exclusively electronic line calling, eliminating line umpires on all but two of its courts. Initial feedback was positive, according to Stacey Allaster, the tournament director, but the U.S. Open has yet to commit to using the same system in 2021.
Electronic line judging would most likely eliminate one current issue: umpires examining the wrong ball mark on the clay, which is a frequent source of tension with players. But if there is a switch to electronic calls, players will still be able to see the mark on clay, and it will not always match what technology records.
“The ball mark can be larger or smaller than the true contact area depending on the amount of clay, humidity of clay, speed of the ball, direction of travel, etc.,” said Stuart Miller, executive director of the science and technical department at the International Tennis Federation.
In other words, players who now argue that the Hawk-Eye image supports them could someday be insisting that the mark proves their point instead. Whatever it takes to win any given point.
“I know you have an issue at the moment, but you’ll have an issue the other way as well,” Cahill said.
“We have a system on clay we have used forever,” he said, adding that chair umpires deserve some credit. “They’ve been doing their jobs for the last 100 years, so I think on clay the system we have at the moment is a pretty good system. If we can better it, I have no problem with that, but you