2019 Issue-4
Can someone explain how the first down and scrimage lines are generated on screen in televised NFL games? Obviously, it's done by computer, but I can't figure out how the angle and aspect is able to change and keep up with the constantly changing camera angles. Also, the lines are seemingly underneath the players, as if they were actually drawn on the ground.
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If you’re in Alexandria VA, you can go to the National Inventor’s Hall of Fame museum and they have an interactive exhibit about it: https://www.invent.org/museum/exhibits
“1st & Ten Line Stadium
Get in the game with the 1st & Ten Line Stadium exhibit, inspired by several game-changing NIHF Inductees. Visitors can step onto the turf to experience the sounds and visuals of a real football game. This hands-on exhibit puts you on the big screen, as you control the placement of the Virtual Yellow 1st & Ten® line, invented by Inductee Stan Honey.”
ESPN Front Row has an article about it that has additional links to the history of the system:
https://www.espnfrontrow.com/2013/09/virtual-yellow-1st-and-ten-line-debuted-on-espn-15-years-ago-today/
https://mashable.com/2013/09/25/yellow-first-down-line/
I hope that helps give Mr. Johnson some resources to read.
The short answer is the TV broadcaster maps out the stadium and instruments the cameras to report exactly where it is focused (tilt, pan, zoom, and focus). Computer processing then overlays the first-down (yellow) line onto each frame of the video. There is a good write-up on the technology here: https://entertainment.howstuffworks.com/first-down-line1.htm.
