Robot umpires are coming to MLB. Here's how they work

A Hawk-Eye pose-tracking system utilizes high-speed cameras to map the ball and the player's anatomy to define the strike zone. Each batter is measured for their specific zone while shoeless, ensuring absolute accuracy. Players undergo this calibration between 10 a.m. and noon daily to ensure consistency, as human height can naturally shorten slightly later in the day. Data is further verified by the Southwest Research Institute. MLB has streamlined this calibration process, estimating it takes less than one minute to measure each player before they take the field.

While traditional umpires often develop a perceived "oval" strike zone based on experience and catchers' framing skills, the ABS zone is strictly rectangular, adhering precisely to the official MLB rule book. Developing a consensus on the digital strike zone proved to be a challenging initial hurdle. By aligning the software with the written rules rather than human perception, MLB hopes to eliminate the variance that has historically caused frustration among hitters and pitchers alike, creating a more objective standard for every plate appearance.