The US Open removed line judges from every court in 2022. The Australian Open had done the same a year earlier. Wimbledon, the last holdout, announced in October 2023 that it would replace its line judges with automated officiating for the 2025 Championships. The ATP Tour followed in April 2023, mandating the technology at all its events from 2025. Professional tennis is replacing human judgment with computer vision, and the shift is powered as much by sponsorship revenue as by accuracy.
Hawk-Eye, the system at the center of that transition, was developed in 2001 by Dr. Paul Hawkins and acquired by Sony in March 2011. Its core technology is a network of cameras that track the ball's position and predict where it lands. The system generates a graphic replay that broadcasters show during challenges. At the US Open and Australian Open, the live version called Hawk-Eye Live calls every line in real time without a human referee signaling out. The result is faster play and fewer disputes, but it also removes a visible human role that had been part of tennis for more than a century.
The Business of Line Calls
Hawk-Eye's role at tournaments extends beyond officiating. The system is a sponsorship asset. Sony sells naming rights, on-screen branding, and integration with broadcast graphics. Tournaments that adopt automated line calling typically sign multiyear deals that include a technology fee and a sponsorship commitment from the provider or its parent company. The exact monetary value of any current deal between Hawk-Eye and a specific tournament is not public, but the structure is standard in sports technology: the vendor pays a rights fee to be the exclusive officiating system, and recoups that fee through broadcast exposure and data licensing.
The ATP's 2023 announcement that it would adopt automated line calling across all its events from 2025 effectively made Hawk-Eye the default supplier for the men's tour. The WTA has not made a similar announcement, but individual WTA events have adopted the system on their own. The International Tennis Federation, which writes the Rules of Tennis, has approved automated officiating as a permissible method. That approval was necessary before any tour could mandate the technology.
Player Tracking and Biometric Data
How Tracking Works
Beyond line calls, the same camera networks that track the ball also track the players. Hawk-Eye and competing systems record movement patterns, shot placement, rally length, and court coverage. That data is sold to broadcasters for on-screen analytics and to coaching staff for post-match review. The ATP and WTA both maintain central databases of match statistics drawn from these tracking systems.
Coaching and Training
Coaching staff now use player-tracking data to identify patterns invisible to the naked eye. A coach can see that a player loses more points when forced to run to the forehand side after a serve to the body, or that a specific opponent wins 80 percent of rallies longer than eight shots. The data is also used in training. Some academies install the same camera systems used at tour events, so practice sessions generate the same metrics that match analysis uses.
Wearables and Regulation
The use of biometric data such as heart rate and sweat rate is less widespread on tour, but common at the academy level. Wearable sensors that measure acceleration, impact force, and muscle activation are used by some national federations and private training centers. The ITF regulates which wearable devices are allowed in official matches, but training sessions are not subject to the same restrictions.
Equipment Regulation and the ITF
Governing the Gear
The International Tennis Federation is the global governing body responsible for the Rules of Tennis, including the technical specifications for rackets, strings, and balls. Any piece of equipment used in an ITF-sanctioned event must comply with the federation's rules on dimensions, weight, string pattern, and rebound characteristics. The ITF tests new racket designs and string materials before they can be used in competition.
The Smart Racket Question
Smart rackets with embedded sensors have been available at retail for several years. These rackets measure swing speed, spin rate, and impact location, and send the data to a smartphone app. As of March 2024, it was not established whether the ITF had approved any specific smart racket for use in official tournament play. The federation has not published a ruling on sensor-embedded equipment as a class. Recreational players and academy students can use them freely, but a professional using one in a match would risk a code violation if the device is deemed to give an unfair advantage or to violate the rule against electronic communication during play.
The Pace of Change
The ITF's approval process is slow by design. Equipment changes that affect the speed or behavior of the ball have implications for the character of the game. The federation has resisted calls to slow down the game by restricting racket technology, but it has also not approved any radical innovation that would change the fundamental interaction between racket and ball.
Fan Experience, Betting, and the Future
In-Play Betting
Real-time data from automated line calling and player tracking feeds into in-play betting markets. Sportsbooks use the same camera data that broadcasters use to set live odds on the outcome of the next point, the number of aces in a game, or the winner of a tiebreak. Integrity monitoring firms cross-reference betting patterns against the same data to detect unusual movement. The availability of high-frequency, low-latency data has made tennis one of the most heavily traded sports in the in-play betting market.
Stadium and Broadcast Shifts
For fans in the stadium, the elimination of line judges changes the experience. The US Open replaced human line judges with automated calls announced over the public address system. Some fans miss the human element. Others prefer the speed and finality of a system that never argues. Broadcasters have added augmented reality graphics that show shot trajectories, serve speeds, and player movement in real time, which changes how viewers at home watch the sport.
What Comes Next
The transition to automated officiating is not complete. Wimbledon will use line judges for one more year, and some lower-tier events cannot afford the installation cost. But the direction is set. The technology that started as a challenge system in 2006 has become the primary officiating method on the biggest stages. The business deals that made that possible are the same kind of sponsorship and data licensing agreements that drive technology adoption across professional sports.
