Preventing unauthorized copying of displayed information by utilizing differences in spectral sensitivity between humans and imaging devices

A method is described for preventing unauthorized copying of information shown on a display. It utilizes the difference in spectral sensitivity between humans and imaging devices. A near-infrared light source, which has no effect on human vision, is installed in front of an existing display to corrupt the content of photographs taken of the display. Testing using a prototype implementation demonstrated that this method effectively prevents the unauthorized copying of displayed information. In addition to preventing the disclosure of confidential and personal information through the unauthorized photographing of displays, the proposed method has broad application to the unauthorized photographing of works of art, factory equipment, and other objects subject to photographic restrictions.