Patent ID: 7426640
Filing Date: 2008-09-16
Classification: G06T

Abstract:
1. A computer readable storage medium storing instructions of a computer program which when executed by a computer results in performance of steps comprising: computing an auto-correlation function of the input image signal by a correlator; accumulating the auto-correlation function for a first period of time to generate a first accumulation signal by a first accumulator; extracting a specific frequency component signal from the first accumulation signal by an extraction unit; normalizing an amplitude of the specific frequency component signal by a normalizing unit; accumulating 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 by a second accumulator; detecting the watermark information from the second accumulation signal, wherein at least one of the correlator, the first accumulator, the normalizing unit, and the second accumulator includes a processor; and controlling, which periodically stops computation of the correlator and increases the second period of time, if the throughput is lower than a threshold value.