What's the current state of strike zone technology?
July 6, 2009 6:06 AM   Subscribe

What's the current state of strike zone technology?

Okay, after a week of watching baseball where the strike zone took the shape of whatever the umpire-of-the-day wanted it to be, I got to wondering. Setting aside the question of whether the strike zone should be determined by technology, could it be? Does the technology exist right now to establish a uniform strike zone and have machines call the balls and strikes?
posted by lpsguy to Sports, Hobbies, & Recreation (7 answers total) 2 users marked this as a favorite
I would assume that there would have to be some sort of technology built in to the ball and/or player uniforms to get the correct reading, and it's not worth the investment, considering how many balls are hit out of play each game. Putting aside umpire preference, the strike zone's upper and lower regions change per batter based on their height, torso length, etc., so it's not like Hawkeye in tennis, where a camera can scan the lines to see if a ball was in or out. A "uniform" strike zone wouldn't be "uniform" at all, or it'd be unfair to the tallest and shortest players.
posted by sjuhawk31 at 6:14 AM on July 6, 2009

ESPN shows replays with a red box indicating the strike zone, and in fact has cross hairs for where the ball went.

If that kind of technology could translate from replay to used live I'm not sure. But if it's not there it's certainly close.
posted by theichibun at 6:37 AM on July 6, 2009

If you haven't read this article about camera angles and the strike zone I'd recommend it. It doesn't directly address your question but it goes to the same idea.
posted by true at 6:44 AM on July 6, 2009

I'm recalling a party conversation from years ago with some guy who worked at a company that did tech like this for pro sports. My understanding is that, yes, the technology exists to have a computerized strike zone and it works just fine, but the traditionalists at MLB want it to never see the light of day. This technology could work even better if they could put a sensor inside the baseball but that is just too much meddling for MLB to bear.
posted by Brian James at 7:52 AM on July 6, 2009

One strike zone detection system would consist of two cameras. The first would detect when the incoming ball crossed a plane just in front of the batter; the second, pointing at this plane instead of across it, would measure the position of the ball as it crossed the plane. Together, the information from the two cameras identify the position of the ball in 3 dimensions as it crossed the plane of the strike zone.

The first sensor might not be a camera at all, but a simpler kind of sensor that works as a photointerrupter (an infrared emitter on one end, and a row of receivers on the other end; if any loses its signal, then it's because the ball "shadowed" it and thus crossed the line between the source and the sensor)

I assume, but don't know for sure, that feature recognition technology is quite good enough to reliably locate the ball in a digital photograph. If not, you could embellish things by using an infrared or ultraviolet camera, and put a special invisible (to humans) pigment on the ball that wouldn't be present elsewhere. That would reduce the image recognition problem to "blob on dark background". Finally, multiple subsequent imges from the second camera could be used to track the ball so its position can still be estimated if simple detection from the crossing frame fails.

Doing it with no extra visible equipment (particularly the first sensor) on the field might be more of a trick. With two bog standard video cameras on home plate, but good feature recognition software, you can also uniquely locate the ball in 3d; take the two frames closest to the crossing of the strike plane, connect the points with a line, and use the intersection of the line and plane to determine whether it passed within the strike zone. Problem: at 81mph, the ball moves at 4 feet per 1/30 second TV frame, so the frame of the ball closest to the strike plane is up to 2 feet away (in front of or behind)

(this is more or less what the umpire does; his two cameras are separated by about 2.5 inches)
posted by jepler at 9:58 AM on July 6, 2009 [1 favorite]

Does the technology exist right now to establish a uniform strike zone and have machines call the balls and strikes?

See Questec:
In 2001, however, the company signed a 5-year contract with Major League Baseball to use its pitch tracking technology as a means to review the performance of home plate umpires during baseball games. The contract has continued through the 2008 season by annual extensions.
Setting aside the question of whether the strike zone should be determined by technology, could it be?

From a technical perspective, sure. Good luck getting the umpires' union (or players, for that matter) on board with it.

Also nth'ing what's said above about the phrase "uniform strike zone" being a bit of a non sequitur.
posted by Doofus Magoo at 10:13 AM on July 6, 2009

You'd probably still need a home plate ump for non-balls & strikes calls, though? It would seem much more difficult for a machine to tell if a player beat the tag. And whether something is passed ball or a wild pitch is very much a judgment call.
posted by Chrysostom at 5:45 PM on July 9, 2009

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