Display-Camera Communication uses commercially available displays as transmitters and cameras as receivers for free-space optical data transmission. Since potential transmitter and receiver hardware can be found in almost all areas of life today, display-camera communication offers an attractive addition or alternative to radio-based data transmission methods. Here, a distinction can be made between covert and non-covert transmission.
In non-covert transmission, the entire screen, or part of it, is used exclusively for data transmission, making the full dynamic range of pixel brightness available. In the case of covert data transmission, the display is still primarily used to display image content, but a data pattern that is barely or not at all perceptible to a human observer is superimposed on this content, which can be decoded using a suitable receiver without significantly affecting the image quality.
As part of the three-year DaVid research project funded by the BMBF, a system for covert data transmission was developed at the Communication Technology Institute. Based on the research results, further system variants were designed, which represent different possible interpretations of the concept. Thus, one variant was developed with the goal of particularly high data rates and one variant with the goal of very reliable transmission of small amounts of data.
Even after completion of the project in August 2020, intensive research will continue in this area at the Communication Technology Institute. Existing system variants will be further developed and possible new approaches will be investigated. In addition, a systematic description of the transmission channel is to be developed in order to derive a suitable channel model and to be able to make statements about the channel capacity of the display camera channel.