摘要:
Disclosed is a method of adjusting a supplementary data signal (wm(n)) to be embedded in an information signal (x(n)), for example an audio signal. The method comprises the steps of determining (301) a position where a predetermined property of the information signal exceeds a predetermined threshold, e.g. an attack position, and suppressing (302) the supplementary data signal in a predetermined neighbourhood of the determined position.
摘要:
methods of embedding and detecting a watermark in an information signal (x(n), y′(n)) which are robust against sampling rate conversions of the watermarked signal (y(n)) adapts frame lengths used by an embedder and the detector, respectively, so as to preserve a constant ratio between the respective sampling rate and frame length. The frame lengths may be calculated from a greatest common divisor of a set of sampling rates providing watermarks which are robust against sampling rate conversions between any sampling rates of the set of sampling rates.
摘要:
The invention relates to a method of checking the correct operation of a signal transformation wherein a input signal is transformed into an output signal. The method comprises: deriving a first robust feature from the input signal; deriving a second robust feature from the output signal; comparing said first and second robust features; in case of sufficient sumilarity, concluding a correct operation of said signal transformation, and in case of insufficient sumilarity, concluding a false operation of said signal transformation. In a special embodiment, the method is applied wherein the first robust feature is embedded in the input signal through watermark technology, the thus obtained signal being transmitted to a receiver so as to retrieve an output signal corresponding to said input signal.
摘要:
A multirate filter according to the invention comprises, a) an input unit (10) for receiving an input signal (Sin) and for providing a plurality of intermediate signals (IS1, IS2) in response to said input signal, b) a filter unit (20) coupled to the input unit (10), and c) an output unit (30) coupled to the filter unit (20), for generating an output signal (Sout). The filter unit (20) comprises at least a first and a second filter module (21, 22), with a transfer function H0(z) and a transfer function H1(z) respectively, which are mutually related according to the relations H0(z)=c0(HB(z)+Mα,ψHB(z)) and, H1(z)=c1(HB(z)+Mα,ψHB(z)) wherein, Mα,ψ(HB(z))=αz−2ψHB*(z−1), and wherein Formula (I), being the z-transform of hb[m]. The multirate filter comprises a combination unit (11) coupled to said filter modules (21, 22) for generating a first combination signal (Ssum) and a second combination signal (Sdiff).
摘要:
A method of updating a database (211) comprising a fingerprint of and an associated set of metadata for each of a number of multimedia objects, A multimedia object and a set of metadata for the multimedia object is downloaded from a file sharing client (101-105). A fingerprint is computed from the multimedia object, and the computed fingerprint and the obtained set of metadata are included in the database (211). The database (211) can be maintained by a central server (210), or be maintained in a distributed fashion by servers (404) running on the file sharing clients (101-105). The database (211) in this way accumulates plural sets of metadata associated with one particular fingerprint. When a sufficient number of sets has been collected, a definite set can be determined using filtering techniques.
摘要:
The invention relates to a method of embedding a watermark W in an information signal P, to a corresponding arrangement for embedding a watermark W in an information signal P, to an information signal with an embedded watermark, and to a storage medium 50 having stored thereon an information signal P with an embedded watermark W. The watermark is embedded in the information signal by deriving sub-patterns Wi from said watermark pattern W, wherein the energy spectrum concentration of each sub-pattern Wi has a dominent orientation. The local weight factors &lgr;(P) for said watermark sub-patterns Wi are determined based on the local energy spectrum of the information signal P in said dominent orientation. Said watermark sub-patterns Wi are locally weighted using said determined local weight factors &lgr;(P). Finally, the locally weighted watermark sub-patterns (Wi) are added to the information signal P.
摘要:
A video watermarking scheme is disclosed, which is designed for the digital cinema format, as it will be used on large projector screens in theaters. The watermark is designed in such a way that it has minimal impact on the video quality, but is still detectable after capture with a handheld camera and conversion to, for instance, VHS, CD-Video or DVD format. The proposed watermarking system only exploits the temporal axis. This makes it invulnerable to geometrical distortions generally caused by such a way of capturing. The watermark is embedded by modulating a global property of the frames (e.g. the mean luminance) in accordance with the samples of the watermark. The embedding depth is preferably locally adapted within each frame to local statistics of the respective image. Watermark detection is performed by correlating the watermark sequence with extracted mean luminance values of a sequence of frames.
摘要:
A digital media recorder and a method of controlling such are provided. During attempts to copy media content, sub-sequences are extracted from an input media sequence. A digital fingerprint of the sub-sequence is calculated and compared with at least one first reference fingerprint from a database. The outcome of the comparison determines the action to take in the further processing. Recording of the input media sequence on a media carrier is either allowed or obstructed, e.g. disallowed. In the case recording of the sequence is allowed, the database is updated with information that the digital media sequence has been recorded.
摘要:
Data is hidden in an information signal by encoding payload in to relative positions and/or polarities of multiple (possibly equal) embedded watermarks. The payload is retrieved by computing the correlation between the watermark(s) and the signal as a function of the position. The distance between peaks of the correlation function represents the payload. In order to precisely detect said distance, even if the peaks are smeared, the correlation function in a window (w1) around one peak (p1) is compared with the correlation function in a similar window (w2) around another peak (p2). This is done for different positions of said windows. The distance (k) between the windows (37,38) for which the correlation functions most resemble each other is the distance representing the payload.
摘要:
A video watermarking scheme is disclosed, which is designed for the digital cinema format, as it will be used on large projector screens in theaters. The watermark is designed in such a way that it has minimal impact on the video quality, but is still detectable after capture with a handheld camera and conversion to, for instance, VHS, CD-Video or DVD format. The proposed watermarking system only exploits the temporal axis. This makes it invulnerable to geometrical distortions generally caused by such a way of capturing. The watermark is embedded by modulating a global property of the frames (e.g. the mean luminance) in accordance with the samples of the watermark. The embedding depth is preferably locally adapted within each frame to local statistics of the respective image. Watermark detection is performed by correlating the watermark sequence with extracted mean luminance values of a sequence of frames.