At the US Open, That Voice Yelling ‘Out!’ Comes From a Computer

Ashleigh Barty of Australia (R) after beating Clara Tauson of Denmark on day four of the 2021 U.S. Open tennis tournament at USTA Billie King National Tennis Center, in Flushing, New York, on Sept. 2, 2021. Robert Deutsch/USA TODAY Sports via Reuters

NEW YORK—Ash Barty, the No. 1 seed at the U.S. Open, watched on match point as her opponent’s backhand sailed long on Thursday, prompting the familiar sound of a linesman yelling, “Out!”

There was no line judge, however. The call was a recording, triggered after an advanced system of cameras known as “Hawk-Eye Live” tracked the ball until it landed out of bounds.