by Jason Snell
How MLB verifies the robot strike zone
(Content warning: Baseball. But I swear, tech folks, you don’t have to be a sports person to think this is cool.)
Computer-generated monitoring of the flight of every pitch in every major-league baseball game has changed how we perceive the game. Every major-league broadcast uses the data. We know the flight of the ball through space and, most importantly, its position as it crosses home plate—the ultimate determination of whether it’s a ball or a strike.
This knowledge has created a controversy—should MLB use this technology to replace human umpires in calling balls and strikes? When I came out strongly in support of a computer-assisted strike zone earlier this year, one of the biggest criticisms I heard was the idea that the technology isn’t nearly as reliable and trustworthy as it would need to be.
Which is why I really enjoyed this story by Clay Nunnally, a baseball scientist for MLB, about how the league verifies the accuracy of pitch-tracking technology at ballparks:
MLB works with the Washington State University Sports Science Lab to independently measure pitch-tracking accuracy in every MLB ballpark. Specifically, WSU performs ground-truth tests at every MLB park. A ground-truth test is designed to precisely identify the position of a baseball during a trajectory event such as plate crossing or pitch release. The ground-truth reference is the standard by which we evaluate the accuracy and precision of in-stadia tracking systems.
Essentially, the WSU lab travels to every ballpark and uses cameras that run at 2500 frames per second and a calibration system to track balls shot from a pneumatic cannon and compare their results to the in-stadium tracking system. The “ground-truth exercise” is performed annually at every MLB park, and additional tests happen during the season as well as whenever new equipment is added.
Is that enough precision to be used in major-league games? I guess that’s for the commissioner to decide. And this is only one way that on-field data is being collected; this ESPN piece by Sam Miller details a single play from last year using positional data, calculated via radar, for every player on the field.
I really enjoy reading about how technology is revolutionizing every aspect of sports and giving fans, players, and executives alike a better understanding of how these games work.