Patent ID: 6570996
Filing Date: 2003-05-27
Classification: G06T,H04N

Abstract:
Apparatus for detection of a watermark in an information signal, comprising:means for receiving said information signal, said signal having therein a series of multi-bit watermark values, each such bit value representing a respective watermark subpattern; means for determining, for each watermark subpattern, a correlation value y(n) indicative of whether or not said subpattern is present in the information signal; means for combining the correlation values of all subpatterns to determine (D) the presence of an applied multi-bit value watermark pattern in the information signal regardless of the multi-bit value of the applied watermark pattern; and means for comparing the correlation values of all subpatterns with a corresponding bit value of the applied watermark multi-bit values to obtain an indication (M) of the extent which the multi-bit values of the detected watermark patterns corresponds to the multi-bit value of the applied watermark pattern.