The Technology Behind the Magic Yellow Line

CurtMonash writes "Fandome offers a fascinating video explaining how the first-down line on football broadcasts actually works. Evidently, theres a lot of processing both to calculate the exact location being photographed on the field — including optical sensors and two steps of encoding — and to draw a line in exactly the right place onscreen. For those who don't want to watch the whole video, highlights are here."

Comments

Re:Flamebait +1

[Joce640k]

If your sport requires special on-screen aids to understand what's happening it's probably overdue for a rethink.

Re:The reason for SI units

[Galrion]

Certainly. Which meter should we use? The one defined by the length of a pendulum whose period is 1 second? No that won't work, gravity is slightly different depending upon where you are on the earth.

Okay scratch that. How about the meter whose length is defined by one ten-millionth the length of the earth's meridian between a pole and the equator? Well no that won't work either because the Earth's surface isn't consistent; it gets flatter/slimmer what have you, like when that undersea earthquake occurred (the one that made the huge tsunami a few years ago). So that means the magical platinum bar (or is it platinum iridium?) from 1840 is actually .2 milimeters shorter than the definition would like you to believe.

Let's try again, maybe the measurement of the specific number of waves of a very precise wavelength from a krypton-89 atom? No too cumbersome; my super spy glasses that let me see wavelengths from atoms are at the repair shop.

Maybe the distance traveled by light in a vacuum in 1/299,792,458th of a second? That's certainly a circular definition. Why not make it 1/300,000,000th of a second so that it's a nice round number? Or sticking to the "metric" simplicity factor, why not 1/1,000,000,000th? Then everything's back to a power of 10 instead of a power of...30th?

WTF?

Why would we want to move to some system that arbitrarily decides we cannot be observant enough without magical tools to calculate some basic length? Or one that changes the definition of its basic measurement every few decades?

At least metric got it right for temperature, evenly distribute degrees across 0 to 100 where 0 is the temperature water freezes at 1 atmosphere and 100 is the temperature water boils, again at 1 atmosphere. Then again... doesn't it matter what impurities are in the water? I mean salt water doesn't freeze at 0...

Give me a rational system that doesn't require highly expensive tools to define and I'll be happy to switch to it.