The computer generated yellow line that indicates the first down has changed the way we watch football forever. But its implementation is a multi-stepped process involving dozens of technologies working in precise tandem.

From optical sensors to audio transmissions, the heaviest lifting is probably done by the color filters that, year after year, become better and better at differentiation the line from the linebacker. This brief video will do a lot to make you appreciate the resourceful crews behind the broadcasts. Click to view