Patent ID: 7398397
Filing Date: 2008-07-08
Classification: G06T

Abstract:
1. A digital watermark detection apparatus which detects watermark information embedded in an input image signal, comprising: a correlator which computes an auto-correlation function of the input image signal; a first accumulator which accumulates the auto-correlation function for a first period of time to generate a first accumulation signal; an extraction unit configured to extract a specific frequency component signal from the first accumulation signal; a normalizing unit configured to normalize an amplitude of the specific frequency component signal; a second accumulator which accumulates the normalized specific frequency component signal for a second period of time longer than the first period of time to generate a second accumulation signal; a detector unit configured to detect the watermark information from the second accumulation signal by determining a polarity of a peak of the specific frequency component signal, wherein at least one of the correlator, the first accumulator, the normalizing unit, and the second accumulator includes a processor; and a controller which periodically stops computation of the correlator to reduce a operation amount of the correlator per unit time, if a throughput of the processor is lower than a threshold value.