Patent ID: 6574348
Filing Date: 2003-06-03
Classification: G06T,H04N

Abstract:
Apparatus for forming an identifier for an input image and for securely marking the input image with the identifier so as to yield a marked image, the apparatus comprising:a processor; and a memory having computer executable instructions stored therein; and wherein the processor, in response to the executable instructions: transforms pixel values for an input image, through a predefined transformation, into a predefined domain so as to define a plurality of transform coefficients; generates a plurality of N (where N is an integer) pseudo-random perturbation values such that each different one of a plurality of randomly defined subsets, of the perturbation values and corresponding ones of the transform coefficients, satisfies a separate corresponding predetermined mathematical constraint, such that all of the perturbation values, in conjunction with all of the transform coefficients, satisfy a plurality of different predetermined mathematical constraints, wherein all the perturbation values collectively define the identifier; modifies each of the transform coefficients by a corresponding one of the perturbation values so as to form a plurality of perturbed transform coefficients thereby; and inversely transforms, through an inverse application of the predefined transformation, the plurality of perturbed transform coefficients to pixel values so as to form output pixel values that collectively form the marked image.