US Patent 7557829 Device that reads data encoded as dots

A system is disclosed for reading data encoded as a series of invisible dots carried on a substrate. The system has a detector that detects the dots on the substrate and outputs a first signal; a decoder interconnected to the detector that decodes the first signal to produce an output signal; and an output device interconnected to the processor that receives the output signal and creates a corresponding human readable output. The dots may be infrared absorbing and the encoding can include Reed-Solomon encoding of the prerecorded audio. The system can include a wand-like arm having a slot through which the photograph is inserted.