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
AssigneeJapan Advanced Institute of Science and Technology
InventorsMasashi Unoki, Ryota Miyauchi, Toshizo Kosugi
Life of this patent
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Abstract
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).
Claims15
A digital watermark detection device comprising:
- a cochlear delay characteristics estimation means for estimating cochlear delay characteristics simulated by a cochlear delay filter in a case where a digital watermark data embedding device has embedded digital watermark data in an acoustic signal, which is digital data, the digital watermark data embedding device applying phase modulation to the acoustic signal using the cochlear delay filter that simulates the cochlear delay characteristics and embedding the digital watermark data in the acoustic signal to which phase modulation has been applied;
- and
- a digital watermark detection means for detecting the digital watermark data embedded in the acoustic signal based on the cochlear delay characteristics estimated by the cochlear delay characteristics estimation means.
A digital watermark detection method comprising:
- (a) a step of estimating cochlear delay characteristics simulated by a cochlear delay filter in a case where a digital watermark data embedding device has embedded digital watermark data in an acoustic signal, which is digital data, the digital watermark data embedding device applying phase modulation to the acoustic signal using the cochlear delay filter that simulates the cochlear delay characteristics and embedding the digital watermark data in the acoustic signal to which phase modulation has been applied;
- and
- (b) a step of detecting the digital watermark data embedded in the acoustic signal based on the estimated cochlear delay characteristics.
A tampering detection device that makes use of a digital watermark, wherein
- the tampering detection device detects tampering with an acoustic signal, which is digital data, after digital watermark data has been embedded in the acoustic signal by applying phase modulation to the acoustic signal using a cochlear delay filter that simulates cochlear delay characteristics, and comprises:
- an acoustic signal acquisition means for acquiring the acoustic signal from outside;
- a cochlear delay characteristics estimation means for estimating the cochlear delay characteristics simulated by the cochlear delay filter;
- an embedded data detection means for detecting embedded data that has been embedded in the acoustic signal acquired by the acoustic signal acquisition means based on the cochlear delay characteristics estimated by the cochlear delay characteristics estimation means;
- a comparison means for comparing the embedded data detected by the embedded data detection means with the digital watermark data;
- and
- a tampering determination means for determining whether or not the acoustic signal has been tampered with based on a result of comparison by the comparison means.
A tampering detection method that makes use of a digital watermark, wherein
- the tampering detection method detects tampering with an acoustic signal, which is digital data, after digital watermark data has been embedded in the acoustic signal by applying phase modulation to the acoustic signal using a cochlear delay filter that simulates cochlear delay characteristics, and comprises:
- (a) a step of acquiring the acoustic signal from outside;
- (b) a step of estimating the cochlear delay characteristics simulated by the cochlear delay filter;
- (c) a step of detecting embedded data that has been embedded in the acquired acoustic signal based on the estimated cochlear delay characteristics;
- (d) a step of comparing the detected embedded data with the digital watermark data;
- and
- (e) a step of determining whether or not the acoustic signal has been tampered with based on a result of comparison.
Dependencies are inferred from the claim text.