The Award Winning First Down Line

For more than 20 years the yellow first down line has been as important to American Football on television as the ball itself. While we may take this humble old line for granted, it has greatly enhanced the sport, transforming American Football into one of the most popular spectator sports in the world.

Designed by Sportsvision, the line first appeared on our screens in 1998, however, this wasn't the first time that Sportsvision had attempted to add technology to the world of sports broadcasting. The yellow down line's technology was based on a previous project of Sportsvision, 'FoxTrax'. In partnership with Fox Sports, Sportsvision was aiming to make the "biggest technological breakthrough in the history of sports". As it turns out, this 'breakthrough' turned out to be a glowing puck that made it easier for fans to follow the puck when watching hockey.

Whether the technology was ahead of its time or just straight up unnecessary, it went on to be ridiculed by sports fans and has even been dubbed "the worst sports broadcasting innovation of our time" by Evan Winiker in this Huffington Post article.

Ignoring the ridiculousness of the techno-puck or glow puck as it is sometimes referred to as, the technology behind this project was quite cutting edge at the time. This was not an ordinary puck in any sense. The puck was gutted and filled with a battery, a circuit board and a whole load of LEDs. These lights were pulsing at an incredibly fast rate so that the lights were not visible to the human eye. However, using infrared technology, the cameras were able to see this flashing and track the movement of the puck. Then the puck was modified and presented as the famous glowing puck.

So where did the techno-puck go? 25 years on and our screens are still not lit up with the glamour of the glowing puck. As it turns out, this technology was reliant on very precarious lighting environments and a very delicate resonator inside the puck, controlling the rate of light flashing. In the perfect conditions of freshly treated ice, even so much as a small exit sign could throw off the cameras. Equally disastrous, the resonator's frequency would often change slightly as a result of being hit too hard, this would throw off the cameras rendering the glow puck a failure.

Despite the resounding failure of the techno-puck, Sportsvision decided to extend their use of computerized images in broadcast sports to the NFL. Unlike the glow puck, the yellow first down line was a huge success and has changed the way we watch football forever. In fact, the line was so popular that Sportsvision even went on to win an emmy for technology and engineering for its efforts.

The virtual first down line uses chroma key technology paint our TV's yellow. Chroma key essentially filters out certain colours by deciding if it is the colour of turf or grass or something else. This works in a similar was to a green screen. With the many shades of grass, the curve of the field, the changing sunlight and shadows and even the various possible weather conditions, this is no easy feat. Camera modelling is also very important to the existence of the first down line. As the camera tilts, zooms and pans, the yellow line must kept in perspective to its surroundings for it to work. Sportvision measures the zoom, tilts and pans in order to assess the angle and size of the line.

As augmented reality and sports become more intertwined, who knows, maybe the techno-puck will return one day

Cian Rellis