It may look like it is part of the field because when players run through the line it appears as if they are standing on top of it. That effect occurs because the technology only displays the yellow color on top of the colors green grass and brown dirt.
The yellow line officially made its debut during an edition of Sunday Night Football, September 27th It was not ready during the first week of the season due to ironing out one final bug, so it was not until week four when it was first aired.
Stan Honey is credited with the invention of the yellow line, working with a company called Sportvision. The technology was called First and Ten and generated an overwhelmingly positive reaction from football fans.
That company was acquired by Rupert Murdoch in ' I ended up being head of technologies for News Corp. I started working with David Hill , who was just then starting Fox Sports. He had just gotten the rights to NHL hockey and he asked me if it would be possible to track and highlight the hockey puck in real time.
We built a system so you'd see a blue highlight around the puck and when the puck was moving fast you'd see a red trail behind it. When Fox lost the contract for hockey, we stopped doing it. I was able to take the patents and technology out of News Corp. Our objective was to find situations in sport that happened a lot and were important to the game but were hard to see on TV.
The first down in football was a perfect example. The whole game of football is all about getting first downs. The way it works is that we have accurate sensors on all the cameras so we're able to measure the pan, tilt, zoom, focus of each of the broadcast cameras.
If you go to a sporting event and look below every camera you'll see a gold box that has the Sportvision logo on it. That's the sensor. Mobile Newsletter chat dots. Mobile Newsletter chat avatar. Mobile Newsletter chat subscribe. Inside the NFL.
How the First-Down Line Works. Football Image Gallery The virtual first-down line that you see in many televised football games is something of a computer-generated miracle. Find out how this line gets "painted" on the field. See more football pictures. The Technology One of the quirkier aspects of computer-generated video effects is the vast amount of effort it takes to do seemingly simple things.
It takes a tractor-trailer rig of equipment, including eight computers and at least four people, to accomplish this task Advertisement. The system has to know the orientation of the field with respect to the camera so that it can paint the first-down line with the correct perspective from that camera's point of view.
The system has to know, in that same perspective framework, exactly where every yard line is. Given that the cameraperson can move the camera, the system has to be able to sense the camera's movement tilt, pan, zoom, focus and understand the perspective change that results from that movement. Given that the camera can pan while viewing the field, the system has to be able to recalculate the perspective at a rate of 30 frames per second as the camera moves.
A football field is not flat -- it crests very gently in the middle to help rainwater run off. So the line calculated by the system has to appropriately follow the curve of the field.
A football game is filmed by multiple cameras at different places in the stadium, so the system has to do all of this work for several cameras. The system has to be able to sense when players, referees or the ball crosses the first-down line so it does not paint the line right on top of them.
The system also has to be aware of superimposed graphics that the network might overlay on the scene. Drawing the Line In order to determine where the line should go, a central computer utilizes several pieces of information: The virtual field modeled from measurements of the actual field taken before the game , and the data from the camera mounts showing each camera's range of view The raw video feed from the camera that's currently on-air determined by a separate computer in the Sportvision production truck Two distinct color palettes , one representing the on-field colors that should be changed to yellow to represent the first down line, and another representing colors that should not be changed like those in the players' and officials' uniforms -- this allows a player to appear to "obscure" the line, making the line appear as if it were really painted on the field.
A spotter and an operator work together to manually input the correct yard line into the system.
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