Mehtod and apparatus for the detection of a digital watermark

摘要

A specific frequency component extraction unit (11) extracts a specific frequency component signal from an input image signal (10). A phase controller (12) controls the phase of the specific frequency component signal. A correlator (13) computes the cross-correlation value of the phase-controlled specific frequency component signal and the input image signal. A watermark information estimation unit (14) filters the cross-correlation value to detect watermark information embedded in the input image signal (10).