摘要:
Method and apparatus are described for compensating for time offset in a received signal, so as to correctly align the frame sequence of a received signal to a sequence of transmitted symbols. Each symbol extends over Ts signal samples. The received signal is first divided into a sequence of frames of length Ts, and then each framedivided into a multiplicity of Nb sub-frames. Subsequently, Nb sequences of values are formed, where every successive value in each sequence is derived from the corresponding sub-frame within each successive frame. Each of the Nb sequences is an estimate for the correctly aligned sequence of transmitted symbols.
摘要:
Method and apparatus are described for compensating for a linear time scale change in a received signal, so as to correctly rescale the frame sequence of the received signal. Firstly, an initial estimate of the sequence of symbols is extracted from the received signal. Successive estimates of correctly time scaled sequences of the symbols are then generated by interpolating the values of the initial estimates.
摘要:
The present invention relates to a method, device (12) and computer program product for enabling detection of additional data embedded in a media signal that may have been subjected to scaling. The invention also relates to an additional data detecting device (10) comprising such a device for enabling detection. An envelope discriminating unit (ED) provides a first extracted narrow band envelope signal sample (we[n]) from an input media signal sample (yb[n]), and a variable scale down sampling unit (VSDS) down samples the narrow band envelope signal sample using a down sampling rate that is dependent on a scaling factor variable value (η) for providing at least one sample of a first additional data estimate (wn[k]) in order to allow the detection of additional data in said signal sample.
摘要翻译:本发明涉及一种方法,装置(12)和计算机程序产品,用于使得能够检测嵌入在可能已经进行缩放的媒体信号中的附加数据。 本发明还涉及一种附加数据检测装置(10),其包括用于使能检测的这种装置。 包络鉴别单元(ED)从输入媒体信号样本(y b b [n])提供第一提取的窄带包络信号样本(w∈En [n])) ,并且可变缩小缩小采样单元(VSDS)使用取决于缩放因子可变值(eta)的下采样率向下采样窄带包络信号采样,以提供第一附加数据估计(w 以便允许检测所述信号样本中的附加数据。
摘要:
A lighting system and a method for a operating a lighting system, enabling to obtain an identification tag (7) comprised in lighting design data (5) directly from an output beam (3), i.e. from the emitted light of the at least one lighting unit (2). It is thus possible to trace any unauthorized distribution of a lighting design by monitoring the emitted light without the need to directly access the controller or any other part of the lighting system.
摘要:
A basic idea of the present invention is to selectively employ one of at least two different feature extraction processes when generating a biometric template of an individual. An individual offers a physiological property, such as a fingerprint, an iris, an ear, a face, etc., from which biometric data can be derived, to a sensor of an enrolment authority. In the following, the property to be discussed will be fingerprints, even though any suitable biometric property may be used. From the fingerprint, a positional reference point of the biometric data is derived. The derivation of the positional reference point may be accomplished using any appropriate method out of a number of known methods. Such a reference point could be the location of a core, a delta, a weighted average of minutiae coordinates, or alike. Typically, the reference point includes a core of a fingerprint expressed as a three-dimensional coordinate denoted by means of xr, yr, and angle αr. A contribution indicator is calculated for the derived positional reference point, and it is determined whether the derived positional reference point can be considered reliable. Depending on the reliability of the derived reference point, one of the two different feature extraction processes is selected; either the first feature set is extracted using a method which is invariant of the derived reference point, or a method is used taking into account the derived reference point. The better the estimation of the reference point is, the more reliable the reference point-dependent extraction method is. Finally, the biometric template is generated using the extracted first feature set.
摘要:
A method of generating a watermark signal, embedding the watermark signal within a multimedia signal, and subsequently detecting the watermark signal is described. The watermark signal is the sum of two sequences of values, the second sequence of values being a circularly shifted version of the first sequence.
摘要:
In watermarking systems, hackers may try to remove the watermark using a so-called collusion attack. If the attacker has access to multiple identical signals with different watermarks (this typically occurs in electronic content delivery systems), simply averaging the signals will remove the watermark energy. A known solution to this problem is phase modulation. By modulating the phase of the signals, the averaging attack will cause phase cancellation to occur and annoying artifacts to be introduced. In the prior art, said phase modulation is carried out in the base-band domain, prior to watermark embedding. The present invention enables phase modification efficiently to be applied to transform coded signals, in particular DCT or MDCT coded signals such as MP3 or AAC audio signals, or MPEG2 video signals. The bitstream is partially decoded (4) and re-encoded (7). In accordance with the invention, the phase modification is now performed by an appropriately modified version of the forward or inverse (M)DCT transform algorithm (9). The phase modulation is thus an integral part of the decoding process (before watermark embedding) or the encoding process (after watermark embedding), which is very efficient. The phase modulation is controlled by parameters provided by a control function (5).
摘要:
A system and a method of effectively detecting watermarks in a significant amount of data signals. The method, in overview, consists in pre-filtering the significant amount of data signals in order to eliminate from the final watermark detection the segments of the data signals which have no significant relevance to the owner of the copyrights of the watermark under investigation, and then performing the actual watermark detection over the remaining segments of data signals relevant to the investigation. The pre-filtering feature being implemented by a definition of one or more goal descriptors, extraction of one or more descriptors from the data signals and its content and a comparison between goal descriptors and extracted descriptors.
摘要:
The invention relates to a system for verifying the identity of an individual by employing biometric data features associated with the individual, which system comprises at least one or more hardware components, an enrollment means, and a verifying means, wherein said enrollment means are arranged in deriving a first biometric template data, said first biometric template data being secret and associated with a first set of first biometric data features of said individual, and in receiving a further set of first biometric data features of said individual, and in deriving a further biometric template data associated with said further set of first biometric data, and wherein said verifying means are arranged in comparing the first biometric template data with the further biometric template data to check for correspondence, wherein the identity of the individual is verified if correspondence exists. The invention aims to provide a solution to the above identified drawbacks and thereto at least one of said hardware components is provided with at least one component specific data feature associated therewith and wherein said enrollment means are arranged in associating at least one of said component specific data features with said biometric template data.
摘要:
The invention relates to a method for generating a representation of a finger print minutiae information. The invention also relates to a method for generating a representation of a finger print for biometric template protection purposes Biometric template protection techniques provide technological means to protect the privacy of biometric reference information stored in biometric. systems These methods stand in sharp contrast to approaches where biometric information is protected only by legislation and procedures around storage facilities. These systems are not reliable as they are susceptible to human and procedural errors. Template protection guarantees the protection of biometric information without the assumption that individuals are trusted or procedures are properly implemented.