Digital watermark detecting device and method thereof

Abstract

There is provided a digital watermarking detecting device that can accurately detect watermarking information weakened by an attack such as image cut-out, scaling or the like without increasing a calculation amount and a circuit scale. The digital watermarking detecting device includes an extractor 10 for extracting a signal of a specific frequency component from a watermarking embedded image, first orthogonal transformers 11A, 11B for calculating an orthogonally-transformed image of an extraction signal and an orthogonally-transformed image of a watermarking embedded image, amplitude adjusters 12A, 12B for adjusting the amplitudes of the two orthogonally-transformed images in accordance with the difference between the amplitude components of the two orthogonally-trans formed images, a compositor 13 for combining the two amplitude-adjusted orthogonally-transformed images, a second orthogonally-transformer 14 for subjecting the composite signal to orthogonal transformation to achieve a second orthogonally-transformed signal, and an estimator 15 for estimating the watermarking information on the basis of a peak appearing in the second orthogonally-transformed signal.

Description

Technical field [0001] The present invention relates to a digital watermark detection device and a method thereof, which can effectively prevent illegal copying of digital video signals provided through a recording medium such as a recording medium. Background of the invention [0002] With the popularization of devices for recording and reproducing digital image data such as digital VTR, DVD (digital versatile disc) or the like, a large number of digital moving pictures that can be reproduced by the above-mentioned devices are provided. In addition, a variety of digital mobile images are being spread through digital television broadcasting through the Internet, broadcasting satellites, and communication satellites, allowing users to use high-quality digital mobile images. [0003] High-quality reproduction of digital moving pictures can be easily performed on the digital signal level. Therefore, if neither copy prohibition nor copy control is imposed on these digital mobile scre...

AI Technical Summary

Problems solved by technology

In addition, this method has a problem in that the amount of calculation and the scale of the circuit increase

In addition, for the image under attack, the watermark information of the image is weakened, so even when the cropping or scaling of the image is detected and the detection adapted to the cropping or scaling of the image is detected, the watermark information may still not be detected

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