Along the field of modern football stadiums there are often 16 cameras that only have to follow the movements of the football players on the field. Seconds after seconds they get a set of 3D coordinates; the positions are therefore represented by x, y and z coordinates.
Because the cameras deliver 25 images per second, this system accurately measures all movements.
The ball and the referee are also followed, and with the aid of the computer the measurements are converted into data about, for example, the distance that a player travels and the speed of the ball.
Derived from rocket systems
The technique is inspired by missile tracking systems.
Tests show that the measurements have a margin of error of no more than three percent. The system was first presented to the public at the European Championships in 2008, but had already been tested the year before, including in the Champions League.
A field player runs on average 10 km
The measurements indicate that a field player in a top match covers a distance of ten kilometers. On average, a football player sprint 800 to 1200 meters during a match, but he only has a clear 200-meter possession of the ball.
1. Up to 16 cameras film the field and the players, each from his own angle. The cameras deliver 25 images per second.
2. A computer combines the images from various cameras and assigns x, y and z coordinates to each player.
3. By following a player from second to second, the computer calculates how long it has been running.
4. The movements of the ball are also followed, so that the system knows how long a goal kick is, for example.