Demo: rollinglight - universal camera communications for single led

Camera communication (CamCom) is a form of visible light communication (VLC) that makes use of a camera as the receiver. One very important advantage of CamCom is that the acquired images during the receiving process provide a means to visually associate the physical object with the transmitted information, since the receiver has the knowledge of which pixels in the images are transmitting. Figure 1 shows a simple example. A user points her smartphone camera at multiple lights, touches the screen to select one, and uses the virtual switch that appears on the screen to adjust the lighting level. In this scenario, the lights simply periodically transmit simple identifiers, such as IP addresses, to the smartphone. The system is able to directly associate what the user sees (the image pixels corresponding to the light selected by the user) to the transmitted information (the identifier of the light). An out-of-band channel, such as WiFi, can then be used to send the actual command to the selected light to adjust the setting. Compared to the conventional approach of identifying a particular set of visual features unique to the object with computer vision techniques, this approach is simpler, more intuitive, and more accurate.