# Football meets technology

**URL:** <https://boards.straightdope.com/t/football-meets-technology/137375>\
**Category:** Factual Questions\
**Created:** [November 18, 2002, 8:20pm UTC](https://boards.straightdope.com/t/football-meets-technology/137375 "2002-11-18T20:20:03Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![CDWinstead](https://avatars.discourse-cdn.com/v4/letter/c/b19c9b/32.png) [@CDWinstead](https://boards.straightdope.com/u/CDWinstead)\
**Post date:** [November 18, 2002, 8:20pm UTC](https://boards.straightdope.com/t/football-meets-technology/137375/1 "2002-11-18T20:20:03Z")

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I was just wondering if anyone knew exactly how the networks paint the virtual first down markers that are yellow during football broadcasts without it covering up players and at different camera angles. The only plausible thing I can come up with is that they use some sort of light-based device aimed at the field that the cameras detect. Any other hunches or definite answers?

First post btw, hello all.

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**Author:** ![Cerowyn](https://avatars.discourse-cdn.com/v4/letter/c/82dd89/32.png) [@Cerowyn](https://boards.straightdope.com/u/Cerowyn)\
**Post date:** [November 18, 2002, 8:41pm UTC](https://boards.straightdope.com/t/football-meets-technology/137375/2 "2002-11-18T20:41:16Z")

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Welcome to SDMB! This topic has luckily been discussed several times. Take a boo at [this thread](http://boards.straightdope.com/sdmb/showthread.php?threadid=143558), for instance.

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**Author:** ![Telemark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/telemark/32/372_2.png) [@Telemark](https://boards.straightdope.com/u/Telemark)\
**Post date:** [November 18, 2002, 8:41pm UTC](https://boards.straightdope.com/t/football-meets-technology/137375/3 "2002-11-18T20:41:56Z")

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Welcome to the boards.

If you do a search you’ll find that this question comes up fairly frequently. Here’s a good explaination.

> **[How the First-Down Line Works](https://entertainment.howstuffworks.com/first-down-line.htm)**
>
> The virtual first-down line that you see in many televised football games is something of a computer-generated miracle that home viewers have come to love. Find out how this line gets "painted" on the field without painting the players.

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**Author:** ![CDWinstead](https://avatars.discourse-cdn.com/v4/letter/c/b19c9b/32.png) [@CDWinstead](https://boards.straightdope.com/u/CDWinstead)\
**Post date:** [November 18, 2002, 8:45pm UTC](https://boards.straightdope.com/t/football-meets-technology/137375/4 "2002-11-18T20:45:26Z")

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I tried searching and, as I’m sure you’ve heard before, didn’t find a topic that matched my question. But thanks for the replies and the warm welcome. Both of them were helpful.

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**Author:** ![CDWinstead](https://avatars.discourse-cdn.com/v4/letter/c/b19c9b/32.png) [@CDWinstead](https://boards.straightdope.com/u/CDWinstead)\
**Post date:** [November 18, 2002, 8:57pm UTC](https://boards.straightdope.com/t/football-meets-technology/137375/5 "2002-11-18T20:57:18Z")

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I tried searching and, as I’m sure you’ve heard before, didn’t find a topic that matched my question. But thanks for the replies and the warm welcome. Both of them were helpful.