Inside a nondescript room in the broadcast complex near Arthur Ashe Stadium, dozens of people are intensely focused on banks of screens that track the movement of every ball and every player on the field courts.
This room houses the staff and equipment responsible for reviewing every challenge made by players on these outer courts, and then sending the graphic representation of the point-ending shot back for display on the screens on the courts.
It's a hub of activity and one of the most technologically savvy areas of the USTA Billie Jean King National Tennis Center. It's here that officials will determine whether a ball just clipped the line or missed it by a millimeter. It's where points are won or lost by the finest of margins and where incorrect calls are rectified. It's the place that gives players peace of mind and where on-court disputes are nullified before they even begin.
Through the first four days of the tournament, there had been 2,031 reviews, including 801 over the first two days of the tournament. By way of comparison, there were 226 reviews in the 2006 US Open, when the technology was only used in Arthur Ashe Stadium and Louis Armstrong Stadium.
Even after four days, the number of challenges had smashed the tournament record of 1,039, set in 2015 after the replay had been expanded to also include the Grandstand (2009), Court 17 (2011) and Court 5 (2014).
"Looking back at some old photos of eight to 10 of us on site [in 2006], it is quite the journey," project manager Oliver Clough said. "I think it is a natural progression of tennis to move to a centralized location on site."
"There is a very technical element to what we do, and there's a very creative part to what we do,"
The US Open this year became the first Grand Slam tournament to offer electronic line calling on every court for all main-draw singles and doubles matches. In doing so, it provides a consistent experience for players and offers fairness and transparency whether a player is in Arthur Ashe Stadium or on Court 15.
At the start of the US Open, the review center in the broadcast complex was responsible for monitoring the action on 13 courts. The other four stadium courts — Arthur Ashe Stadium, Louis Armstrong Stadium, Grandstand and Court 17 — have dedicated replay booths inside the stadium as part of the broadcasting facilities.
The room is divided into zones, each one further separated into each court. Each work area has a bank of six monitors. Two monitors on the left of the desk track the precise movements of the players and ball in real time from 10 different camera angles, offering a multi-color graphic representation of movement. On the right side of the desk is a pyramid of three other monitors.
These show the match information display, the camera angle from the baseline to the right of the umpire's chair and a mosaic of four different TV camera angles in case any of the other feeds fail. In the middle of the desk is a sixth monitor, a computer-generated 3D virtual world that is used to display the animation of the electronic line call review when it is displayed on the videoboards in the stadia. Within 0.1 seconds of a player or ball moving, their position on the court is shown and updated in real time.
"There is a very technical element to what we do, and there's a very creative part to what we do," Clough said, pointing to the virtual court that is shown in every replay. That 3D model was made by Jack Pesterfield who also works as a systems engineer tracking the flight of the ball and movement of the players during matches in Flushing Meadows this year.
In addition to video, there are also multiple lines of audio, both to and from the chair umpire. The two people in the replay bunker can hear the umpire's microphone, as well as the ambiant sound of the court, including lines judges' calls and the voices of players. They have three ways of communicating with the umpire, again with redundancy in mind in case one of the other methods fails. There's a peer-to-peer microphone that goes directly into the umpire's earpiece, a direct land-line phone that connects with the phone in the umpire stand and a hand-held radio.
"This is a more centralized approach," Clough said. "We have redundancy in everything we do."
It took approximately 1,000 man-hours for the Hawk-Eye team to set up for the US Open, and as many as 55 members of staff were working in the booth at the peak of the action. Clough arrived on site 16 days before the US Open started.
At the desk dedicated to Court 11 on this day, two people — a systems engineer and a replay official — are watching the men's doubles first-round match between Henri Kontinen and John Peers against Jeremy Chardy and Fabrice Martin.
"It's a pretty well-oiled machine on Day 6. The key thing is that it doesn't hold up play."
With Chardy and Martin leading 5-4 in the final set, Peers hits a 30-15 serve that is called out. The ball was close to the center line and even before Peers motions to object to the call, the review official, a certified chair umpire, had told the systems engineer to stand by because she had heard the lines judge's call.
That started a chain of events of the engineer pulling the digitized version of that serve, based on the 3D mapping of the 10 cameras working together. By the time Peers told the umpire that he wanted to challenge the out call, the review official had confirmed that the vizualization selected by the engineer was the correct point in question and it was already cued up in the system.
The chair umpire made the official announcment through the on-court PA system that Peers was challenging the call on the center service line and that the ball was called out. As soon as the review official heard this, she sent the video of the replay directly to the scoreboard on Court 11, showing the ball was, in fact, 10mm wide.
From start to finish, the whole process took fewer than 10 seconds.
"It's a pretty well-oiled machine on Day 6," Clough said. "The key thing is that it doesn't hold up play. There's a fluidity to play. It's a nondescript room but what goes on inside is very important. It's pretty exciting."
