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公开(公告)号：EP1309972A1
公开(公告)日：2003-05-14
申请号：EP01969552.7
申请日：2001-07-31
CPC分类号： G11B20/1876 , G11B20/10009 , G11B2020/00065
摘要： A method of concealing errors in a single bit bitstream x(n) comprises low pass filtering (F) the bitstream, replacing the low pass filtered signal during an error (EF) by a low frequency approximation (J) of the signal u(n) and subsequently converting the signal by a ⊤Δ-modulator (SO) into a regenerated single bit bitstream y(n). During the absence of an error the original bitstream x(n) may be outputted and during an error the regenerated bitstream y(n), which is obtained from a ΣΔ-modulator (SD), which is bit-synchronized (SU) to the original bitstream x(n).
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公开(公告)号：EP1891608A2
公开(公告)日：2008-02-27
申请号：EP06765706.4
申请日：2006-05-23
发明人： VAN DER VEEN, Minne , KEVENAAR, Thomas, A., M. , BRUEKERS, Alphons, A., M., L. , AKKERMANS, Antonius, H., M. , WILLEMS, Franciscus, M., J.
CPC分类号： G06F21/32 , G06F21/31 , G06F21/6245 , G07C9/00158
摘要： The invention relates to a method of authentication of a physical object and an apparatus applying said method. The method uses a helper data (Wl) and a control value (Vl) associated with a reference object to generate a first property set (Cl) using the helper data (Wl) and a metric (Y) associated with the physical object. It further comprises a step to generate a second property set (Sl) using a noise compensating mapping (NCM) on the first property set (Cl), as well as a step to establish a sufficient match between the physical object and the reference object using the second property set (Sl) and the first control value (Vl). The method is characterized by a step that generates an error measure (ERR) by quantifying the noise removed by the noise compensating mapping (NCM) using the first property set (Cl) and information derived from the noise compensating mapping (NCM). Error measure (ERR) is subsequently used for generating an authentication decision (D). Also provided is an apparatus configured to carry out the method.
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13.发明授权
公开(公告)号：EP1393315B1
公开(公告)日：2006-11-15
申请号：EP02724543.0
申请日：2002-04-19
发明人： BRUEKERS, Alphons, A., M., L. , HAITSMA, Jaap, A. , KALKER, Antonius, A., C., M. , VAN DER VEEN, Minne
CPC分类号： H04H20/31 , G06T1/0064 , G10L19/018 , G11B20/00086 , G11B20/00891
摘要： Disclosed are methods of embedding and detecting a watermark in an information signal (x(n), y'(n)) which are robust against sampling rate conversions (102) of the watermarked signal (y(n)). The frame lengths used by the embedder (101) and the detector (103), respectively, are adapted 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.
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公开(公告)号：EP1692874A2
公开(公告)日：2006-08-23
申请号：EP04799212.8
申请日：2004-11-23
IPC分类号： H04N7/26
CPC分类号： H04N19/59 , H04N19/13 , H04N19/132 , H04N19/14 , H04N19/176 , H04N19/18 , H04N19/40 , H04N19/467 , H04N19/48 , H04N19/93
摘要： The invention relates to a system for re-encoding bitstreams for content signals. A re-encoder (101) receives a bitstream comprising e.g. an MPEG-2 encoded signal. The receiver (109) feeds the bitstream to an extraction processor (111) which extracts non-essential information from the bitstream thereby generating a reduced bitstream which is still MPEG-2 compliant. The non-essential information, which specifically may be higher frequency transform coefficients, is re-encoded in a re-encode processor (113) using a non-MPEG-2 encoding principle. The encoding may be optimised for the characteristics of the non-essential information resulting in a more efficient encoding. The re-encoded data is inserted in user data section of the reduced bit stream by a combine processor (115). Thus, an effective reduction in the size of the bitstream may be achieved. A decoder (107) may extract the re-encoded data from the user data section, regenerate the original non-essential information and insert this in the reduced bitstream. Specifically, the original bitstream may be regenerated. The approach may specifically be used for reversible bitstream watermarking that which does not increase the size of the bitstream.
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公开(公告)号：EP1393314B1
公开(公告)日：2006-07-26
申请号：EP02724542.2
申请日：2002-04-19
发明人： VAN DER VEEN, Minne , BRUEKERS, Alphons, A., M., L. , HAITSMA, Jaap, A. , KALKER, Antonius, A., C., M.
IPC分类号： G11B20/00
CPC分类号： G11B20/00891 , G11B20/00086
摘要： Disclosed is a method of embedding a watermark in an information signal (x(n)), such as an audio signal. The method comprises the steps of segmenting the audio signal into overlapping frames (xs(n)) using a set of analysis windows (ha(n)), calculating watermark segments (ws'(n)) for the overlapping frames, reconstructing a watermark signal (w'(n)) from the watermark segments using a set of reconstruction windows (hr(n)) which are complementary to the analysis windows, and adding the watermark signal to the information signal. The analysis and reconstruction windows may be constructed on the basis of prototype windows to fulfil predetermined complementary conditions. The analysis and reconstruction windows may be adapted to the contents of the information signal.
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16.发明公开
公开(公告)号：EP1665789A1
公开(公告)日：2006-06-07
申请号：EP04769860.0
申请日：2004-08-26
CPC分类号： H04N21/235 , G06T1/005 , G06T2201/0063 , G10L19/018 , G11B20/00086 , G11B20/00144 , G11B20/00891 , G11B20/00905 , H04N1/00005 , H04N1/00037 , H04N1/32144 , H04N1/3232 , H04N21/435 , H04N2201/3239 , H04N2201/327
摘要： The invention relates to watermarking systems, which irregularly change the embedded watermark so as to avoid hacking the system by averaging-attacks. In averagingattacks, 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.
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17.发明公开RAISING DETECTABILITY OF ADDITIONAL DATA IN A MEDIA SIGNAL HAVING FEW FREQUENCY COMPONENTS 有权增探测概率附加数据在媒体信号中很少的频率分量
公开(公告)号：EP1639826A1
公开(公告)日：2006-03-29
申请号：EP04736871.7
申请日：2004-06-15
CPC分类号： H04N1/32149 , G06T1/005 , G06T2201/0052 , G06T2201/0065 , G10L19/018 , H04N1/3216 , H04N1/32203 , H04N1/32352 , H04N7/08 , H04N2201/327
摘要： The present invention relates to a methods, devices, a media signal as well as an information storage medium related to embedding additional data in a media signal. A first adding unit (12) mixes the media signal (x) with a noise signal (n) in order to provide a modified media signal (x + n), and a combiner unit (14) combines additional data (w) with the modified media signal (x + n) through multiplying the modified media signal with the additional data in order to provide a host modifying media signal (mw). In this way the additional data can be detected with a higher certainty in an output signal (y) if the media signal (x) includes few frequency components.
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公开(公告)号：EP1634275A2
公开(公告)日：2006-03-15
申请号：EP04733896.7
申请日：2004-05-19
CPC分类号： G10L19/018 , G06T1/0035 , G06T2200/28 , G06T2201/0052 , G10L19/002 , G10L19/0204 , G10L19/167 , G11B20/00086 , G11B20/00891 , H04N5/913 , H04N9/8042 , H04N2005/91335
摘要： The present invention relates to methods, devices, a media signal and a recorded medium for watermarks embedded in the sub-band domain of compressed media. Watermarks (w[n]) are embedded into the sub-band signals (xi-1[n], xi[n],xi+1[n]) of at least one selected sub-band of a compressed bit-stream (bk) using a watermark inserting unit (18). In this way there is no need to fully decode and re-encode the media signal for embedding the watermark. The watermark is embedded in selected sub-bands (e.g. sub-bands 7-15 of 32). In a preferred embodiment, the selected sub-bands are upsampled before embedding and downsampled therafter to avoid aliasing. The invention also allows embedding multiple watermarks in different sub-bands (e.g. one watermark in sub-bands 7-11, and a different watermark in sub-bands 12-16).
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19.发明公开MULTIRATE FILTER AND A DISPLAY SYSTEM AND A MOBILE TELEPHONE COMPRISING SAID MULTIRATE FILTER 有权更多加过滤器和图像显示系统，移动电话的多种速率FILTER
公开(公告)号：EP1570574A1
公开(公告)日：2005-09-07
申请号：EP03775675.6
申请日：2003-12-04
IPC分类号： H03H17/06
CPC分类号： H03H17/0275 , H03H17/0276 , H03H17/0685
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-2ψ 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).
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公开(公告)号：EP1525557A1
公开(公告)日：2005-04-27
申请号：EP03740978.6
申请日：2003-07-07
发明人： BRUEKERS, Alphons, A., M., L. , HAITSMA, Jaap, A. , VAN DER VEEN, Minne , KALKER, Antonius, A., C., M.
IPC分类号： G06T1/00
CPC分类号： G06T1/005 , G06T2201/0052 , G06T2201/0065
摘要： A watermark detection method is disclosed which is based on computing the cross-correlation between a suspect signal and a watermark. In order to be more robust against prolonged dominant signal components that adversely affect the correlation, the sequence of signal samples (61) to be correlated with the watermark is divided into sub-sequences (A(k)). The sub-sequences are processed, by a weighting function, to obtain modified sub-sequences (B(k)) that individually exhibit the original signal variations, but collectively (62) exhibit a flatter distribution of sample values. Dominant peaks in the signal are thereby substantially reduced.
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