Abstract: The invention relates to a method of authenticating a physical object using a helper data and a control value associated with a reference object, the method comprising: acquiring a metric data of the physical object, generating a first property set using a noise compensating mapping on input data derived from information comprising said helper data and metric data, establishing a sufficient match between said physical and reference object using said property set and control value. The method further comprising a step to generate a noise measure, the step comprising the following sub-steps: reconstructing the output of a noise robust mapping generated during the enrolment of the reference object using the noise compensating mapping, and generating the noise measure by calculating the difference between the input to the noise compensating mapping and the output of the noise robust mapping. Also provided are an apparatus and system configured to carry out the method.

Abstract: The invention concerns a method and apparatus for embedding and detecting watermarks in a digital host signal. In the embedding method a watermark sequence of length Lw/N bits carrying predetermined information is generated and then up-sampled by a factor N (preferably N=2). At intermediate sampling points of the up-sampled sequence a modified version of the watermark sequence (in preferred arrangements the negative thereof) is inserted to form a compound watermark sequence of length Lw. The compound watermark sequence is then combined with the host signal to watermark the host signal. The invention finds particular advantage in that the need for a spectral whitening stage in the detector is done away with.

Abstract: The invention relates to watermarking systems, which irregularly change the embedded watermark so as to avoid hacking the system by averaging-attacks. In averaging attacks, segments of the watermarked signal are accumulated. This causes the host signal to be cancelled out whereas the embedded watermark accumulates coherently. A watermark A thus determined is then subtracted by a hacker from the watermarked signal. This invention exploits the insight that the hacker does not know when the embedded watermark changes (from A to B, or from A to none). Accordingly, fragments of the hacked signal will contain the negative watermark—A being unintentionally embedded by the hacker. This causes the watermark detector to produce a correlation peak of opposite polarity. The invention resides in the detection of such a negative peak, and concluding therefrom that the signal has been tampered. The payload of the watermark is preserved. This provides the possibility to trace back the hacker.

Abstract: The invention relates to methods, devices, a system of devices and a signal where additional information is embedded in media content. The system includes a device (10) providing additional information (O, D) in a signal (y) having media content, comprising a first mapping unit (14) mapping the amplitude values of the media content onto first new values, and a multiplexing unit (16) inserting the additional information into the mapped media content. The system also includes a device (12) for receiving additional information (O, D) in a signal (y) having media content, comprising a demultiplexing unit (22) arranged to receive a signal including media content (xQ) the amplitude values of which have been mapped onto first new values together with additional embedded information (O, D), and remove the additional information from the mapped media content. The invention allows insertion of watermarks into media content such as audio.

Abstract: A method of processing an information signal comprising: applying a signal modification process to an information signal resulting in a processed signal, said signal modification process being controlled by at least one control parameter; comparing the processed signal with the information signal to determine a measure of perceptual quality of the processed signal; and adjusting said at least one control parameter in response to the determined measure of perceptual quality. The method is advantageously used in watermarking and compression systems, that use a model of the Human Auditory or Visual System to control the watermark embedding depth or the compression ratio, and that often fail to maintain a constant signal quality because they ignore other artifacts than the mask-to-noise ratio.

Abstract: In order to enable a data signal, such as an audio or video signal, to be marked with multiple watermarks a set of different codes or keys is used within a given application field. The set of codes/keys is known to a watermark embedder (20) and a watermark detector (22). In each watermark embedding step, whether it is a first embedding step or a subsequent embedding step, a different key is used. The embedder (22) includes a data extractor (24) for determining which key or keys has or have been used previously. A data generator (26) then selects a new key from the set of known keys.

Abstract: In order to promote its “xxx” signal encoding algorithm, company X offers users of a particular encoder (21) the possibility to up-load (parts of) their .xxx files to the company's website. The company's web-server (1) checks whether the received file is indeed xxx-encoded material by (i) decoding the file using an xxx-decoder (11), (ii) deriving a fingerprint (12) from the decoded signal, and (iii) awarding the owner if the derived fingerprint corresponds to one of the fingerprints stored in X's database (14). A possible award is the transmission, to the user, of metadata associated with the signal such as title, artist, lyrics, etc.

Abstract: 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)+M?,?HB(z)) and, H1(z)=c1(HB(z)+M?,?HB(z)) wherein, M?,?(HB(z))=?z?2?HB*(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).

Abstract: The invention relates to an information carrier (101) intended to be put into a rotary motion, said information carrier (101) comprising: -display means (102) for displaying image data, -motion -compensation means (103) applied to said image data for motion-compensating said rotary motion. Use: Optical disc/Optical disc player.

Abstract: Identification of a digital media sequence is performed by an encoding and a decoding process. A sequence is received and its digital fingerprint is computed. A database lookup based on the fingerprint produces one or more matches that all resemble the computed fingerprint to a certain degree. If there is more than one match, at least one attempt is made to detect a watermark in the sequence. If a watermark is found, at least part of the watermark is extracted and used to select one of the matches among the sequences that resemble the media sequence to be identified.

Abstract: Methods and apparatus for embedding a watermark in a multimedia signal and detecting the watermark, are described. The method comprises the steps of generating a watermark signal comprising a first sequence of values and a second sequence of values; obtaining a first signal portion corresponding to a first channel and a second signal portion corresponding to a second channel from the multimedia signal, said channels being significantly independent; generating a first host modifying signal as a mixture of the first signal portion and the first sequence; generating a second host modifying signal as a mixture of the second signal portion and the second sequence; and generating a watermarked multimedia signal by combining scaled versions of the host modifying signals with the multimedia signal.

Abstract: System for performing telemetric measurements, comprising a plurality of mobile communication devices (100), each communication device (100) being provided with at least one sensor (110) and a sensor control section (120) for performing measurements, a cellular communication network structure for the mobile communication devices, a server provided with communication means for receiving measurement data from the plurality of mobile communication devices (100), and for sending measurement instructions to respective sensor control sections (120) of the mobile communication devices (100) wherein the sensor control sections (120) are programmable by the server.

Abstract: Watermark embedding is often used to identify multiple copies (Qi) of the same content (Q). Each copy (Qi) is provided with a different private watermark (Wi) which, for example, identifies the player on which that copy may be reproduced. Private watermarks can be hacked. Averaging two or more watermarked copies may cause any of the private watermarks to become undetectable. The watermark embedder (10) in accordance with the invention embeds a global (fixed) watermark (W) in addition to the private watermark (Wi). The global watermark is the same in each copy and therefore remains detectable. Its presence indicates that a private watermark shall be present as well. It can be used in a protocol like: no playback allowed if the global watermark is present and a private watermark is not found.

Abstract: 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 (107) a relative magnitude (g(n)) of a first property function (Mx(n)) of the information signal averaged over a region of a predetermined size and a second property function (Mwm(n)) of the supplementary data signal averaged over said region; and adjusting (407) the supplementary data signal according to the determined relative magnitude.

Abstract: A method of controlling access to a resource (140) using a verifying device (130). A watermarking device (110) embeds an authorization code in a signal (120) using watermarking technology. The watermarked signal (120) is then transmitted to a verifying device (130), e.g. as a television or radio program or as a commercial related to the resource (140). In the verifying device (130), the authorization code is extracted from the watermarked signal (120) and an operation to be performed on the resource (140) is authorized in dependence on the extracted authorization code. Preferably the authorization comprises permission for executing a program (231), rendering and/or copying a multimedia object (213) or for activating a cheat function in an electronic game (220).