Currently, if you want to know more about an item displayed in front of you, one of the most common methods of doing so involves scanning its QR code ... if it has one. The problem with those codes, along with things like RFID and NFC tags, is that they detract from the appearance of the item. Fujitsu Laboratories, however, has developed an alternative system. It uses the light shining on the object to convey data.
The system incorporates existing RGB LED lights, which are able to emit red, green or blue light (or any mixture thereof) from a single bulb.
Ordinarily, such bulbs are kept at a single color setting, which can even just be a neutral white-ish color. In Fujitsu's system, though, the light rapidly fluctuates between emitting red- and blue-tinted light – the red pulses represent 0's in binary code, and the blue ones represent 1's.
The fluctuations are so rapid, and the tints are so subtle, that the human eye simply sees the bulb's output as continuous white lighting. A mobile device running the proper software, however, is able to detect the code in the light reflected off the displayed item – it's even able to compensate for the fact that some of the light is absorbed by the surface of the object. Upon reading the coded instructions, the device responds by displaying informational content, navigating to a website, or doing whatever else is stipulated.
Other systems do already exist, that use factors such as GPS coordinates, Bluetooth signals or rapidly-flickering overhead lighting to relay information. According to Fujitsu, however, those technologies are limited to relatively wide areas, and can't be focused down to use on individual objects.
Along with simply providing information on things like products or museum artifacts, the system could conceivably also be used to pay for purchases on the spot, download music that's currently being performed live, or to provide commentary on self-guided tours.
Source: Fujitsu