DIGITAL WATERMARK DETECTION DEVICE AND DIGITAL WATERMARK DETECTION METHOD, AS WELL AS TAMPERING DETECTION DEVICE USING DIGITAL WATERMARK AND TAMPERING DETECTION METHOD USING DIGITAL WATERMARK

摘要

A digital watermark detection device includes a first chirp z-transform unit (202a) and a second chirp z-transform unit (202b) for estimating the cochlear delay characteristics simulated by cochlear delay filters that were used in embedding digital watermark data in an acoustic signal. The digital watermark data embedded in the acoustic signal is detected based on the cochlear delay characteristics estimated in accordance with the result of chirp z-transform applied by these first chirp z-transform unit (202a) and second chirp z-transform unit (202b).