When viewing sports coverage from other countries, it's common to see sideline advertising boards that are promoting products you've never even heard of. A new TV system is capable of digitally replacing the content of those boards, so they're advertising region-specific products.
The technology was developed by a team from Germany's Fraunhofer Institute for Intelligent Analysis and Information Systems, and is currently being marketed by Swiss firm ViboTec. It incorporates LED sideline advertising boards, which ordinarily display ads as a series of still electronic images, each one lasting 20 milliseconds.
In the new system, however, each image is displayed for just 18 milliseconds. For the other two milliseconds, the boards show a blank magenta screen. Because it appears for such a short time, that screen isn't visible to the human eye – so spectators in the stadium simply see the default local advertising content.
The frame rate of the TV cameras covering the game, however, is set so that they only record their frames of video when the magenta screen is showing. As a result, the unprocessed video continuously shows the boards as being blank magenta. Utilizing a chroma key process – in which one solid color is electronically replaced with other video imagery – regional broadcasters can then swap their own advertising into those spaces.
Because the angle at which the boards are shot is constantly changing as the cameras move back and forth, all of the cameras are equipped with motion-tracking modules. These modules continuously track the pan and tilt of each camera in real time, prompting the system to compensate by digitally changing the perspective of the chroma-keyed advertising so it matches that of its respective board.
And when players step in front of the boards, they still show up over top of the added advertising – just like your local TV weather-person appears over top of the map, when they're actually standing in front of a green backdrop. Additionally, should one of the teams have magenta uniforms, the color used by the system can be changed to another.
Fraunhofer is now adapting the technology for use in ultra-high-definition 8K broadcasts.
Source: Fraunhofer