TECHNIQUES OF IMPERCEPTIBLY ALTERING THE SPECTRUM OF A DISPLAYED IMAGE IN A MANNER THAT DISCOURAGES COPYING

摘要

Copying of visual images by electronic devices is discouraged by metamericallyaltering the relative weights of the color components forming the visualimages in a manner that is not perceptible to the human eye (70) but which isperceptible in the copy (90). In a preferred technique, the visual images arerepresented by more than three primary color components whose relative valuesare varied in this manner. A primary application is to discourage copying byvideo cameras of movies displayed on theater movie screens, by causing thecopies to contain unacceptable spatial or temporal variations in colorsperceived by the human eye (70).