July 2008

Measurement: Radar guns are the old days

Watching baseball is an art form and takes years to develop.

Major League Baseball (MLB) has added some visual dynamics to the mix and some see the enhancement as moving spectators from looking at stick figures on cave walls to Rembrandt at the Louvre.

Since 2006, MLB has spent $4 million installing sensor cameras in major-league stadiums that can track and record the trajectory of every pitch.

The system, called Pitch f/x, made its public debut in the 2006 postseason. This season it is operational in all 30 major-league parks reported The Wall Street Journal.

It measures the break, or off-line movement, of each pitch to an accuracy of within one inch, calculates the speed of the ball near its release point and at home plate, and creates an image of the ball's arc that is visible on a computer screen. MLB.com offers the service as part of its baseball viewing packages.

Pitch f/x starts baseball down the path of learning how players do things, which batter hits the ball the hardest, which shortstop has the quickest reflexes, what pitcher has the nastiest slider.

It showed, for instance, St. Louis Cardinals pitcher Adam Wainwright had one of baseball's most violent curve balls in 2007, with up to nine inches of vertical drop and more than seven inches of horizontal movement.

Perhaps consequently, Wainwright had an unusually high rate of swings-and-misses against his curve-38% versus a league average of a little more than 25%.

"Instead of saying, 'there's a hard smash to third base' we could say, 'that ball was hit 106 mph, and the third baseman had a third of a second to react.' " said Peter Jensen, a statistician who has written for the Hardball Times, a baseball analysis site. MLB.com reported on the preparations for each game.

Before groundskeepers work on the mound and plate areas during the afternoon preceding a typical night game, a crew is on the field placing spiked and colored/numbered markers on the first- and third-base lines, as well as a marked eight-foot pole at home plate.

This is the "registration" process and is captured by three field cameras at high/behind home plate, high first base, and center field, so the information is then stored into the truck computer software to create the grid that will allow the game's pitch-tracking to happen.

The center-field camera is for two purposes, most important for sizing the batter. For the software to find the ball there needs to be a different plane of location for Matt Holliday than for Kazuo Matsui, who is smaller in stature than Holliday.

Then the crew in the truck sizes each player during batting practice, so during the game each tracking plane is pre-set and remembers that player during each of his subsequent at bats.

According to Kurt Meyer, a broadcast engineer for SportVision, a technology partner with MLB, "a guy stands at home plate with the eight-foot pole and marker, and then the software takes about 20 minutes to snap the grid into place. That tells each of the computers where home plate is in relationship to the three cameras, so they're all on the same page."

The pitch-tracking system is set from 40 mph to 120 mph. That prevents the system from picking up an empty popcorn bag floating past a camera. Manual intervention also comes into play in the occasional event that a third baseman will charge in on a batter who has squared around to bunt while a pitch is coming.

"What we're tracking is very accurate pitch trajectory and speed, and of course, location as the ball crosses home plate," said Justin Shaffer, senior vice president of new media for MLB Advanced Media. "Radar guns do a couple things. Sometimes average speed, sometimes after it crosses the plate, sometimes as it leaves the hand. It's not just focused on the ball.

"We take a series of high-speed photographs, 30 frames per second, as the ball moves from mound to plate. At each frame, we can identify the location of the ball. Therefore, if we take the time of that frame, we can calculate speed. Radar guns are the old days. It doesn't get any more accurate than this."

See the video of Pitch f/x at www.isa.org/link/pitchfx.

Nicholas Sheble (nsheble@isa.org) writes and edits Automation Update department.