Speaker 1: Welcome to brain Stuff from how stuff works dot com
Speaker 1: where smart Happens. Hi and Marshall brain with today's question,
Speaker 1: how do they superimpose the first down line onto the
Speaker 1: field on televised football games? This is one of those
Speaker 1: things that sounds really simple in theory, but it ends
Speaker 1: up being incredibly complicated when you actually try to do it.
Speaker 1: The system that ESPN uses to paint the line is
Speaker 1: called first and ten and it's created by a company
Speaker 1: called sport Vision. The simplest description of the system is this,
Speaker 1: The first down line is drawn on the field with
Speaker 1: the computer so that viewers seeing the game on TV
Speaker 1: can see the line as though it were painted on
Speaker 1: the field. Here are some of the problems that have
Speaker 1: to be solved in order for this system to work. First,
Speaker 1: the system has to know the orientation of the field
Speaker 1: with respect to the camera so that it can paint
Speaker 1: the first down line with the correct perspective from the
Speaker 1: camera's point of view. Second, the system has to know,
Speaker 1: in the same perspective framework exactly where every yard line is. Third,
Speaker 1: given that the camera person can move the camera, the
Speaker 1: system has to be able to sense the cameras movement tilt, pan, zoom,
Speaker 1: and focus and understand the perspective change resulting from that movement. Fourth,
Speaker 1: a football field is not flat. It crests very gently
Speaker 1: in the middle to help rainwater run off, so the
Speaker 1: line calculated by the system has to appropriately follow that curve. Five.
Speaker 1: The football game is shot by multiple cameras at different
Speaker 1: places in the stadium, so the system has to do
Speaker 1: all this work for several different cameras. Six, the system
Speaker 1: has to be able to sense when players, referees, or
Speaker 1: the ball cross over the first down line so it
Speaker 1: doesn't paint the line on top of them. And seventh,
Speaker 1: the system has to be aware of superimposed graphics that
Speaker 1: the network might overlay on the scene. There are probably
Speaker 1: several other complications as well. It's a tough problem. To
Speaker 1: solve these problems. The creators of the first intense system
Speaker 1: combine hardware and software. First, each camera must have very
Speaker 1: sensitive encoders attached so it can read the cameras angle, tilt, zoom,
Speaker 1: and so on and send that information to the system.
Speaker 1: The system must also have a detailed three D model
Speaker 1: of the field so that it knows where each yard
Speaker 1: line is by integrating the tilt, pan, and zoom information
Speaker 1: with the three D model, the system can calculate where
Speaker 1: the line should go. Then the system uses color palettes
Speaker 1: for the field and for the players, referees, and balls
Speaker 1: to recognize pixel by pixel, whether it's looking at the
Speaker 1: field or something else. This way, only the field gets painted.
Speaker 1: According to the sport Vision website, all of this computation
Speaker 1: requires a lot of equipment. There are eight computers, three
Speaker 1: sets of special encoders, and a lot of wiring dedicated
Speaker 1: to generating the virtual first down line in video format.
Speaker 1: Who would have thought that it would be this complicated.
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