While doing some background reading for my 2010 Hardball Times Annual article, I ran across an interesting article about the development of the FoxTrax hockey puck in 1995 and 1996. The system was developed by Fox Sports to allow their TV broadcast to superimpose a blue glow around the hockey puck and add a comet trail to slap shots to help new American hockey viewers follow the action.
What does this have to do with baseball, you ask? [Dora the Explorer-like pause for you to ask.] I’m glad you asked. Let me tell you.
The development of the FoxTrax puck is part of the history that gave us PITCHf/x. The people involved in the FoxTrax development were expert engineers in fields like navigation electronics from Etak, radar systems from defense think-tank SRI International, and video effects from Silicon Graphics. Many of these people went on to found Sportvision, including current Chief Technical Officer Marv White, Sr. VP of Engineering Ken Milnes, and Chief Scientist Rick Cavallaro.
One of the chief treats associated with my attendance at the 2008 PITCHf/x Summit was an hour sitting in Ken Milnes’ office with Alan Nathan talking sports engineering. Among other things, Ken showed us a FoxTrax hockey puck and talked about its development. So I had some idea of the technical ancestry of PITCHf/x and the engineering challenges that Sportvision and its FoxTrax predecessor had tackled. But the interesting thing about this article by Rick Cavallaro was the detail with which he described the engineering challenges involved and how the FoxTrax team took on and solved each one. If you’re interested in engineering and how it applies to sports, I highly recommend you read the whole article.
I’ll give just a few highlights here as they relate to PITCHf/x, HITf/x, and the upcoming FIELDf/x. The FoxTrax team had to learn about cameras–tracking the pan, tilt, and zoom of broadcast cameras and correcting for lens distortion. These lessons have direct applicability to tracking the orientation of the PITCHf/x cameras and reversing the effects of their lens distortion.
They developed an x-y-z coordinate system for the ice rink and method for registering the location of objects detected by the cameras in this coordinate system. This registration system has been adapted for the calibration of PITCHf/x cameras to an x-y-z coordinate system for the baseball diamond. They also learned about the on-the-ground tricks required for wiring up systems at hockey arenas and connecting them up to their broadcast truck, lessons later applied during the PITCHf/x installations during 2007 and the ongoing maintenance of those systems.
If this topic interests you, check out another telling of the same story and of Sportvision’s history.