Digital watermarking of digital audio is performed by Fourier transforming digital audio data, wavelet transforming the magnitude components of the Fourier transform coefficients of the digital audio data, discrete cosine transforming a watermark signal, multiplying the sign of the wavelet transform coefficients of the magnitude components to the coefficients of the discrete cosine transformed watermark signal, adding the coefficients of the Fourier transformed digital audio data and the adjusted discrete cosine transformed watermark signal, and inverse wavelet transforming the audio signal's coefficients before inverse Fourier transformation to finally generate watermark-embedded audio signal data.
A watermarking system comprises an encoding data processor operable to generate at least one marked version of an original item of material by introducing one of a predetermined set of code words into a copy of the original material item. The encoding processor comprises a code word generator operable to form the code word by generating a plurality of code word coefficients, and an encoder operable to combine the code word coefficients with the material item, and an adaptation processor. The adaptation processor is operable to adapt the strength of the code word coefficients or the material item samples in accordance with a relative sensitivity of the material item samples to carry the code word coefficients. The strength of the watermark is therefore adapted in accordance with the sensitivity of the material item to carry watermark code word coefficients. As a result there is a reduced likelihood of an attacker identifying parts of the material item to which the watermark code word has been added. A likelihood of a successful attack is thereby reduced whilst maintaining a desired false negative detection probability.The watermarking system finds particular application in identifying a point of distribution of pirate copies of video material generated by capturing the watermarked image, using, for example, a camcorder in a cinema.
A color conversion module 42 carries out color conversion of original color image data G.sub.rgb from the RGB color system into the CMYK color system to obtain color-converted original color image data G.sub.cmyk (step S104). A DCT module 44 applies DCT (discrete cosine transform) over the whole color-converted original color image data G.sub.cmyk to generate DCT coefficients D.sub.cmyk (step S106). An embedding module 46 embeds the watermark information s into the components C, M, Y, and K of the DCT coefficients D.sub.cmyk (step S108). An IDCT module 48 applies IDCT (inverse discrete cosine transform) onto DCT coefficients D'.sub.cmyk with the watermark information s embedded therein to generate embedding-processed color image data G'.sub.cmyk (step S110). The color conversion module 42 carries out color conversion of the embedding-processed color image data G'.sub.cmyk from the CMYK color system into the RGB color system to obtain embedding-processed color image data G'.sub.rgb (step S112). This arrangement does not require any correction of the position or the shape of image blocks in the process of extracting the embedded watermark information.
This invention provides an image processing apparatus and method, which embed a digital watermark having strong robustness against geometrical transformation/edit processes such as rotation, scaling, translation, and the like, and an image processing apparatus and method, which can accurately extract the embedded digital watermark even after the conversion/edit process such as rotation of an image or the like. A Fourier transformer (901) converts an image input from an image input unit (900) into amplitude component data, and phase component data. An envelope ring pattern generator (902) generates an embedding pattern of digital watermark information, which is expressed by a set of lines that define a circle as an envelope, on the amplitude component data. An envelope ring pattern embedding unit (903) embeds digital watermark information at predetermined positions on the line. An inverse Fourier transformer (904) computes the inverse frequency transforms of the amplitude component data embedded with the digital watermark information using the phase component data.
An implementation of a technology is described herein for the protection of rights in the content of a video sequence. This technology further generally relates to a technology facilitating embedding imperceptible, de-synchronization-resistant watermarks in video sequence and facilitating detecting such watermarks. These watermarks are resistant against unintentional and intentional modifications. In particular, the watermarks are resistant to de-synchronization. In addition, the watermarks are perceptually invisible. The watermarks are hidden in the video so that flicker is minimized or eliminated. More specifically, this technology hides a watermark (of portions thereof) over one or more regions of successive frames. Each region has a center defined by a hash value. A watermark (of portions thereof) is encoded into the region in a "plateau" manner. The mark (of portions thereof) is fully encoded in the frames surrounding the region's center, but trail off towards the edges of the region. This abstract itself is not intended to limit the scope of this patent. The scope of the present invention is pointed out in the appending claims.
An implementation of a technology is described herein for deriving robust non-local characteristics and quantizing such characteristics for blind watermarking of a digital good.
