How Hawk-Eye replaced hundreds of line judges at the U.S. Open

Since 2022, the U.S. Open has had no line judges. Instead, the tournament uses Hawk-Eye Live, an electronic line calling system, to judge whether a ball is in or out. In 2011, Sony purchased Hawk-Eye and the company has grown since then. Hawk-Eye covers the majority of tennis tournaments on the WTA and ATP tours and has a presence in the MLS, NFL, WNBA and soon the NBA. CNBC traveled to the U.S. Open to speak with the Hawk-Eye team to understand how it works in tennis and other major sports.