Patent ID: 6546114
Filing Date: 2003-04-08
Classification: G06T,H04N

Abstract:
Apparatus for testing an input image to determine whether a predefined identifier is embedded within the 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; separately calculates, using N predefined perturbation values, a predefined mathematical function for each one of a plurality of K subsets of the predefined perturbation values and corresponding ones of the transform coefficients to yield K test values, each of the subsets being formed of a predefined number of between 1 and N of the predefined perturbation values and corresponding ones of the transform coefficients (where K and N are both predefined integers with K less than or equal to N), the identifier being collectively defined by the N perturbation values; and determines, in response to the test values, whether the perturbation values associated with a majority of the subsets are present in the image so as to generate an indication signifying that the identifier is present in the image.