Drawing the line Drawing the line (February 08, 2002)

By Candice Shih

Remember the yellow first-down line on broadcasts of last Sunday's Super Bowl? It was never really on the field in New Orleans; it is actually an electronic image that has its origins in Mountain View.

Sportvision, a developer of electronic sports broadcasting aids, is headquartered in New York City but houses its research and development office here.

Its best-known development is "1st & Ten," the virtual first-down line that appears painted on the football field during televised games. In a survey conducted by Harris Poll Online, 92% of football viewers want to see it in all games, not just NFL and select NCAA games, and 83% of those 18 and over actively notice it.

"1st & Ten" is significant to football fans because it shows a crucial element of the game that is normally hard to see.

The line is also subtle. It's designed such that the yellow line appears under the players, referees, ball, and anything else that passes over the actual line.

"We try to make the presentation unobtrusive. It doesn't get in the way of the game at all," said Marvin White, Sportvision's executive vice president of engineering.

In each televised game that features "1st & Ten," a crew of four people and five computers is dedicated solely to that feature.

The yellow line is tacked on by a computer to a virtual football field, so that prior to the game there is a virtual match of the game field.

This is accomplished by mapping the contours of the real field _ which might not be flat _ and then calibrating each of the three play-by-play cameras.

As avid fans of TV football may have recognized, the yellow line stays faithful to the 1st down line even when the camera pans, tilts, or zooms.

This is possible because the cameras at the two 25-yard lines and at the 50-yard line relay their movement information to attached computers. This information travels through a cable to Sportvision's broadcast truck where the "1st & Ten" computers then make the adjustments for the yellow line.

After the signal gets sent from the cameras to the computers, the yellow line is added and the signal gets broadcast to the public. The luxury of being able to see the yellow line costs viewers a "two-thirds second delay," said White.

"One of the other challenges is to synchronize the data perfectly ... or the line is misplaced," he added.

The cadre of people and computers is there to make sure this doesn't happen. Two crew members, one inside the stadium and one in front of a computer, are dedicated to communicating the position of the real first down line to a computer. Another is a troubleshooter. The last controls color variations _ not of the line but of what the line is drawn on.

The reason that the line appears under the players is because the computer is trained to draw the line on the green-colored grass or white-colored chalk of the major yard lines. Rainstorms challenge this technology because they distort the lighting of the green field and create brown-colored mud.

White admits, "It's hard with the Green Bay Packers on Astroturf in sunlight."

Even before Sportvision was Sportvision, Stan Honey, the company's president and chief technology officer, developed tracking on hockey pucks. In 1996, hockey pucks which appeared red to television viewers were introduced.

Suspected of being hard to watch because it was too fast, FOX hockey broadcasts featured the ultimately unpopular puck, which was easier to distinguish among the players and their sticks.

Sportvision was subsequently founded on January 1, 1998. "1st & Ten" was developed for football, and "K-Zone" for baseball.

Only seen on ESPN's Sunday Night Baseball, "K-Zone" is what White calls a "jelly strike zone." Shown live, it marks the volume of space where a pitch must be thrown to be a strike.

Sportvision has also made its mark on broadcasts of NASCAR races through "RACEf/x." Its technology allows networks to attach virtual flags to cars so it's more obvious to viewers which car belongs to whom.

Sportvision allows the capability for virtual dashboards in which speed, acceleration, and brake information for any car can be displayed. In addition, these broadcasts use Pace Chase, which shows the position of a car relative to the leader, and Speedtraps, which show the speed of each car passing through a given point.

"RACEf/x" uses sensors on the cars' brakes and Global Positioning Systems, differentiated so that cars' positions can be calculated to within centimeters, to determine this information.

Sportvision has also developed analytic aids for watching golf and tennis such as Virtual Caddy and ShotTracker.

According to White, Sportvision will use similar technology as "RACEf/x" to "flag" competitors at speed skating events at the upcoming Winter Olympics. Skaters will be tracked and their speed and acceleration calculated.

The developers will also be aiding in the broadcast of aerial skiing events at the Olympics. The skiers' heights will be calculated in a similar manner in which Sportvision determines jump height in broadcasts of NBA games.

Having enhanced the watchability of most of the country's major sports, Sportvision is now focusing on its Winter Olympics products and the enhancement of its current products, said White.