Putting that yellow line on the football field is hard

October 16th, 2007 | Posted by PostmanR

By now, it’s a foregone conclusion that when you flip on FOX or CBS on a lovely autumn afternoon, that yellow line is going to be smack across the first down line on professional football fields across the country. Seems like an easy enough process, right? Wrong, buddy. Very, very wrong. It is, in fact, a very difficult process involving a whole bunch of different factors.

Which, you know, seems somewhat illogical — but this is what it is nonetheless.

As it turns out, implementing this is incredibly complex. It takes a tractor-trailer rig of equipment, including eight computers and at least four people, to accomplish this task!

Here are some of the problems that have to be solved in order for this system to work:

* 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 the 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 cross over 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.

Yeah, that’s a lot of information to swallow and probably goes beyond any loose blockquote rules in the blogosphere, but I do it to emphasize a point. This ain’t easy, folks. So remember: next time you see your local 1st & Ten worker, tell him or her thanks. Because, really, they’re doing the Lord’s and Allah’s work, all in one fell swoop.

{Via Fark.}