Off the ice, onto the field

Meanwhile, unwilling to disband his crack team, Honey needs another project—fast. An idea for a fancy new telestrator for commentator John Madden's play diagrams goes nowhere, but once again, Hill has another idea. "Why don't you just do the first-down line?" he asks Honey. "It's clean, it's simple, and it's important." (The telestrator as described by Honey is, nevertheless, developed later and introduced in 2002.)

This time, though, Murdoch does not bring out the checkbook. Honey and his team, along with two News Corp. executives, Jerry Gepner and Bill Squadron, spin out a new company, Sportvision, taking rights to use all the patents and other intellectual property they have from the hockey puck project. In exchange, News Corp. gets 10 percent of the company.

The color map conundrum

Drawing a simple first-down line has got to be much simpler than continually tracking a puck bouncing around and traveling at up to 160 km an hour, right? Wrong. While some elements of the first-down line problem are similar to some in the hockey puck problem—you have to know where the cameras are pointed at all times and figure out where in the image to do your drawing—a number of factors make the seemingly simple task of drawing a line actually more difficult.

For one, the line has to be drawn as if it were under the players, not as an overlay. Also, the distortion of the television lenses becomes more critical—if the puck trail is a little off, it's no big deal, but if the yellow line is curved incorrectly, it is immediately apparent next to the real white lines on the field. That lens distortion changes constantly as the cameras zoom in and out. Complicating all of this is the fact that, unlike hockey rinks, which are flat, football fields are not—they have a crown down the middle to allow drainage.

But the biggest problem of all is the color "keying."

Color keying is done all the time in broadcast television and movies. The classic example is the weather forecaster in front of a blue screen; the image in the blue screen is later replaced by a video image of a weather map, and it looks as if the weather forecaster is in front of the map. This type of keying is simple; the processor simply replaces any blue pixel with the second image. If a pixel is not blue, it doesn't replace it. When this technology is being used, actors simply do not wear anything blue or parts of them would seem to disappear.