By Isaac Warren
Print Editor
SPRINGFIELD – Anyone who has watched a football game on television has seen the famous yellow line at least once. It’s that computer-generated line used to visualize where the first down must take place. The technology is amazing, and the story behind it is even better.
In 1978, the idea for a marker on the field was conceived by David W. Crain. He pitched his idea to ABC News and to the CBS Technology Center. Both companies decided that his idea was good, but that the broadcast industry “was not ready” for his idea.
This technology was used in hockey games instead. By replacing the traditional puck with one filled by sensors, a blue glow was emitted on the screen, highlighting the puck’s location. A red tail would appear if the hockey puck was shot over 70 miles per hour.
Hockey fans did not enjoy this idea, however, and the idea was scrapped later on.
Twenty years later, ESPN programmer Gary Morgenstern brought the idea back to life. On Sept. 27, 1998, the yellow line was introduced into American homes. On Thanksgiving day of the same year, CBS aired its own version of the first and 10 line.
In order for the line to appear on the field correctly, preparations must be made. Since all football fields are not uniform, each field is scanned by lasers at least once a season. A 3-D model is then generated from the scans.
Three cameras are used to broadcast each football game. The cameras have four encoders that record and transmit the angle of the pan, tilt, focus and zoom. This data can be transmitted 60 times a second to computers. The data from the cameras is then used to draw the line on the field, depending on what is happening in the game.
Since the field is green, broadcasters use a technique in movies to prevent the yellow line from being drawn over the players. Green screen technology is used, since the football field is green. Referring to the 3D model, the colors of the field and team colors are input into the computers. Using this information, the computer can detect when a player walks over the yellow line.
This system works the vast majority of the time, except in extreme weather conditions. Blizzards have been known to cause a problem, because the field is covered in snow and visibility is low. The computer is not as efficient at not drawing the line over players due to the conditions. However, if the field becomes covered in snow, the system can be used to draw the yard lines on the field. This is very helpful for broadcasters and easier for viewers watching on television to see exactly where the players are on the field.
The yellow line technology is always advancing and improving. NASCAR has used this idea to provide driver information on the screen while it follows a certain car. Many companies have also been known to have ads shown with this technology. Advertisements can now be shown on the field and on the walls of baseball games. The NFL has banned any such advertising because it is distracting.
Isaac Warren can be reached at [email protected]