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The Technology Behind the Magic Yellow Line
Posted by
timothy
on Fri Jan 09, 2009 02:33 AM
from the don't-eat-the-yellow-line dept.
from the don't-eat-the-yellow-line dept.
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."
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New trend (Score:5, Interesting)
Hmmm... A new trend? No longer reading 'have not RTFA' but 'have not Viewed TFA'? /. coming to.
Dear oh dear, what is
Re: (Score:2)
Re:New trend (Score:5, Funny)
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Watch the video (Score:5, Interesting)
I already knew in pretty significant detail how all this works, but there was a lot of additional information in the video that never made it to the PR-sanitized behind-the-scenes descriptions of the technology.
Plus, you get to see the ugly UI that appears to have been built as an afterthought - just like the UI of all the other industrial television software I've operated.
Re:Watch the video (Score:5, Insightful)
Plus, you get to see the ugly UI that appears to have been built as an afterthought - just like the UI of all the other industrial television software I've operated.
It's true, 90% of software that I've used in a television studio has a poorly designed, or worse, broken, user interface. Gets the job done but in the most convoluted way. The only well made interfaces are the ones by major companies who have been around for a while, ie Newtek, Adobe, Pinnacle, Chyron.
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Re:Watch the video (Score:5, Insightful)
Well, when you have a user base in the dozens, and operating the UI is the user's entire job, it doesn't have to be intuitive or even easy. It's cheaper to teach a few dozen guys how to use a bad UI than it is to design and program a really good UI.
Honestly, the UI in the video didn't seem too bad though (from a 10-second impression). Sure it was ugly but it seemed to have useful features for the operator; did you notice when the guy dragged the line of scrimmage past the first down marker it automatically reset the first down marker to +10 yards?
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Re: (Score:3, Insightful)
I have developed this maxim:
Software quality is indirectly proportional to it's cost and/or user-base.
I worked at a company that charged millions of $$ for it's software, including up to $1M to fly someone out to install it. It was the biggest steaming pile I ever witnessed.
Re:Watch the video (Score:4, Insightful)
Unfortunately you'll have the word "unfamiliarity" thrown right back at you. It's a bigger hurdle than you might think.
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Re:Watch the video (Score:5, Informative)
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I thought the niftiest part was using the second audio channel to pipe modem tones to the broadcasting booth. I always love an interesting hack...
My Idea For a Football Field (Score:5, Interesting)
Would be a field that uses clear/transparent turf. and all colors on the field are defined by lights under it. The white in the 10/20/30... could be done dynamically, the end zones could be designed dynamically and relit, heck, you could switch from a green field to Boise State's blue.
This could be used to make the same field a football field, soccer field, lacrosse, field hockey... all without the the clutter of all the lines on one field.
This might be tricky with turf technology currently, but I feel like a first technology to do this might be a basketball court (lights for basketball, volleyball, etc)...
It probably isn't feasible, but would be interesting.
Re:My Idea For a Football Field (Score:5, Interesting)
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Re:My Idea For a Football Field (Score:4, Funny)
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Re:My Idea For a Football Field (Score:5, Funny)
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Re:My Idea For a Football Field (Score:5, Funny)
You're thinking a bit too far ahead, I think. I say we just hack some Roombas with spraypaint cans and GPS and let them sort it all out.
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Thanks for that - if I'd been drinking at the time, you'd now owe me for a new keyboard.
Re:My Idea For a Football Field (Score:5, Funny)
Lessee. The football field is 360 by 160 feet. You need a resolution of at least 1 inch This is very coarse, really, but let's say it's 1 inch. This means your field is a giant 4320 by 1920 color screen right here. Which is, like, quad HDTV or something like that. You know what? Fuck the game, let's see some movies.
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Re:The reason for SI units (Score:5, Insightful)
"First of all, when someone writes "football" on slashdot. Is he referring to what is commonly known as "football" all over the world, i.e. "soccer" or what is commonly referred to all over the world as "american football"?"
Sometimes a single word has more than one meaning, especially among different cultures. When that is the case, you have to use something called context to derive which meaning the word has. So "football" could mean a few different things when written on Slashdot depending on who wrote it. Lucky for us, we're given a LOT of context here. Given that we're talking about first down lines and there's ample video showing the sport in question, the context should be pretty obvious. But since you're confused, what they're referring to would likely translate to "American football" in your vernacular.
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People should be doing everything from measurement to arithmetic in hexidecimal (base 16) these days. SI is obsolete in the information age. Although it might be nice to replace the abcdef numerals with something non-alphabetic.
Seriously.
You can draw all the same arguments that were made for the metric system and apply then to why we should switch everything to base 16.
Floating-point operations are generally performed on a base-2 representation of a base 10 number, so conversion errors are common. Base-1
Origins of units (Score:3, Interesting)
I'm a big fan of metric, but I can still see a lot of sense on imperial units, even though I don't use them a lot except for the conventions that have survived like time measurement. There are some really weird units, but imperial's major strength is that its most common units tend
Re:The reason for SI units (Score:5, Insightful)
The traditional system of measurement that exists here rarely causes significant difficulties in every day life.
200g of steak mince per person. 17 people. I'll have 3400g please.
6oz of steak mince per person. 17 people. 102oz... but I can't ask for that. How many pounds?
Large bottle of vodka: 1 litre. 1000mL. Double measure: 50mL. Bottle has 20 double measures.
Normal bottle: 0.75L. 15 double measures.
I think you buy vodka in a "fifth", a fifth of a gallon, and I think a double measure would be 2 fluid ounces. Erm...
My wall: 4.37m by 2.39m. Area: 4.37m*2.39m = 10.4m^2. The can of paint covers 10m^2, damn.
Your wall: 14 feet 4 inches by 7 feet 10 inches. Area... 172in * 94in = 16168 square inches ~= 112 square feet. The paint covers 10 square yards, is there enough? (No)
I don't really see how the benefits would outweigh the costs of forcing people to switch over. Many things are already labeled with both sets of units anyways.
Due to pressure from the EU ;-).
I have a set of SI wrenches and a set of "standard" wrenches.
That's twice as many wrenches as you'd need if everything came with one system of fixings.
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xkcd saves the day! (Score:4, Funny)
And really, if you've lived with non-metric units all your life, it is easy. I have no problem knowing what size and 8 oz tenderloin or 16oz strip steak is or how big it is. I'd be completely lost trying to, off the top of my head...buy or cook with metric units. When I college in a lab, sure, no problem in doing chemistry experiments in metric, but, that isn't real every day life stuff.
I know how to dress when it is 72F outside. I'd have no clue what to dress for at something like 32C (random temp)...
A handy guide to converting to metric [xkcd.com].
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Re: (Score:3, Insightful)
What possible difference could it make whether or not you can personally directly measure the base units?
Re: (Score:3, Interesting)
The reason we use base 10 is b/c we have 10 fingers. If we had 13 fingers, we'd operate in base 13 natively (hmmm.... there's a good thought experiment... what would be some outcomes of operating in a prime base?).
And your comparison is bad.
Quick, what's 125234380034 in base 12 multiplied by 12
What's 125234380034 in base 12 multiplied by 10
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You see the OLED display used by China during the opening games? Just a bit bigger, and they would've been able to implement your idea. You just need a buyer now.
Weathermen have been doing this for ??? (Score:5, Insightful)
Re:Weathermen have been doing this for ??? (Score:5, Informative)
There are several substantive differences:
I'd read the article if it weren't slashdotted, it appears very interesting...
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Re: (Score:3, Informative)
The green or blue weather map is a straight chromakey, the matted background is opaque and the removed background is monochromatic. The first-down line/overlays have to be added to a surface of varying (but reasonably predictable) colors, and it's laid over the action, with objects "in front" (not grass) matted out of the overlay. This is very complicated.
What's more interesting is that it works in Green Bay, [wikipedia.org] where the field may randomly switch from green to white in a matter of minutes, and the player's on the field are wearing green.
Re:Weathermen have been doing this for ??? (Score:5, Insightful)
Don't forget the live component. There is a big difference between a movie where you have 6-18 months to add in FX, and a TV broadcast which is at best delayed a few seconds. In a movie you can conceivably tweak your algorithms to catch the unexpected or clean up a few frames by hand if needed. With live the whole thing needs to work in realtime automatically.
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Re:Weathermen have been doing this for ??? (Score:5, Insightful)
Yeah, I remember very clearly when I first saw the "magic yellow line" some years ago. I watched for a couple minutes before I realized what the line meant. I turned to my friend and asked "You know what that yellow line means?"
He said "Yeah, that's where they have to go for a first down."
I said, "That too. But what the line really means is that you can't believe live video any more."
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Re:Weathermen have been doing this for ??? (Score:5, Interesting)
What really brought it home (so to speak) for me was baseball. If you look carefully, occasionally you can notice that the advertising behind the batter doesn't quite move with the rest of the frame when the camera shakes. While the yellow line couldn't be taken as really existing, you could believe the advertising was actually on the wall.
While that's harmless enough, it shows that convincing covert alterations in real time are also possible.
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Here in Denmark they have (at least on one of the national channels, don't watch the other) switched the blue/green screen with a huge plasma/LCD TV, it works just as well without the hassle of additional processing.
Speaking of TV processing, CNN is using a really cool technology for "3D" interviews: http://gizmodo.com/5076663/how-the-cnn-holographic-interview-system-works [gizmodo.com] . (Note, they call it hologram, but it is by no means holographic, it's just a very cool way of presenting interviews, the guy in the st
The only yellow lines in Australia... (Score:4, Funny)
Flamebait +1 (Score:5, Funny)
I thought Football was a game played with your feet! What the article discusses is a bastardised form of Rugby.
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Re:Flamebait +1 (Score:4, Insightful)
Football doesn't require you to know where the magic yellow line is at to understand what's happening. The refs seem to be able to do it as well as the 22 players on the field or more on the sidelines. It's there on screen is the first down markers aren't always visible. If the shot is zoomed in on the play, a ref's standing in front of the marker, etc you can't visually see where the first down point is at.
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Re:Flamebait +1 (Score:5, Insightful)
If the IOC hadn't dropped Rugby from the summer games it'd be interesting to see how developed Rugby in America would be. The reason for the padding, like it or not, is that American football developed into a game with much larger, stronger, faster, players rather than a slogged out game of endurance. It's not a question of superiority or toughness, there are few American football players who I think would be able to play an entire Rugby match in the style they play now, on the other hand I don't see a lot of Rugby players who I think would particularly effective on the NFL field trying to push around guys who would regularly 100lbs heavier and who are built and trained to be very good at pushing for 40 seconds at a time then taking a break.
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The reason for the padding, like it or not, is that American football developed into a game with much larger, stronger, faster, players rather than a slogged out game of endurance.
the helmets are there to prevent head injuries, and the padding is there to protect people's bodies from the helmets
Youtube Mirror for the video (Score:5, Informative)
Amazing... (Score:3, Funny)
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The referees of the NFL (which I am not) would tend to disagree. I'm not trying to start a sports discussion off-topic but remember that the yellow line is only for home viewers. The measurments of the first down are very exact once the referee makes the initial spot of the ball. The NFL will NEVER take away that power from on-field persons...but back to the yellow line. TV viewers have a perspective which selects only the players at the start of the play that eventually
cool (Score:2)
It's not just the yellow line (Score:5, Informative)
Not being a sports fan, I don't see much of this stuff, but I once visited the company in Silicon Valley that makes the gear. [sportvision.com] The "yellow line" is one of the easier applications. It's basically a camera with encoders driving a fairly simple video processor. Calibration is manual; there's a setup display that shows the normal lines of a football field, and someone aligns the corners to match the real image from the camera. When the generated image matches the real one, the system is in alignment.
That's 1998 technology. The newer systems have gone way beyond that. Ads on billboards are sometimes replaced using the same system. Ads you see on the air may not be what people in the stadium are seeing. There's player tracking, ball tracking, the "virtual strike zone" for baseball, GPS-based tracking for NASCAR, and virtual billboard insertion into everything.
Re:unreality TV -- digitally inserted ads (Score:5, Interesting)
That's true, but I was always more fascinated by the stuff they did for NASCAR. Not only do they use on-screen tech, but they also make use of GPS to do those fancy graphics showing info on the cars while they're moving on the road.
There was an article about this particular tech NASCAR uses in some magazine, but I can not for the life of me remember it, nor can I find any videos demonstrating it...
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And it was awesome that Pixar reproduced these glitches in the opening scenes Cars.
Re:nerdiness (Score:5, Insightful)
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Why "scan" the image? (Score:2)
They didn't say how it was calibrated but let's face it, there's two guys sat there constantly tweaking it so I'm pretty sure the initial pre-match calibration will be done manually.
The only clever part is the camera tracking and perspective correction.
And the interesting part is how they transmit the data round, switching between audio, over the hidden TV lines, etc.
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Scanning the image lets the computer know the exact pixel for each yardline at various pan, tilt, and zoom points, from which it can then correctly interpolate for all the movements. With enough computer power, scanning the image would be all that is needed and the sensors would be moot.