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    SYSTEMS AND METHODS FOR AUTHENTICATION OF PRINT MEDIA
    1.
    发明公开
    SYSTEMS AND METHODS FOR AUTHENTICATION OF PRINT MEDIA 有权
    系统和方法进行验证媒体

    公开(公告)号：EP1579622A1

    公开(公告)日：2005-09-28

    申请号：EP03790079.2

    申请日：2003-11-26

    申请人： Digimarc Corporation

    发明人： RODRIGUEZ, Tony, F. ,  REED, Alastair, M. ,  SHARMA, Ravi, K. ,  ALATTAR, Osama, M. ,  HANNIGAN, Brett, T. ,  LEVY, Kenneth, L. ,  BRUNK, Hugh, L.

    IPC分类号： H04L9/00 ,  G06F11/30

    CPC分类号： H04N1/00846 ,  H04N1/00002 ,  H04N1/00005 ,  H04N1/00037

    摘要： This disclosure describes methods for using embedded auxiliary signals in documents for copy detection and other applications. In an application, the auxiliary signal is formed as an array of elements selected from a set of print structures (106) with properties that change differently in response to copy operations. These changes in properties of the print structures that carry the embedded auxiliary signal are automatically detectable. The extent to which the auxiliary data is detected forms a detection metric used in combination with one or more other metrics to differentiate copies from originals. Robust and fragile watermarks are used in Image Replacement Documents for a variety of applications. Digital watermarks act as on-board mediators in authentication of a variety of printed documents. Finally, digital watermarks are used to help manage quality of the scanners used in imaging systems.

    SYSTEMS AND METHODS FOR AUTHENTICATION OF PRINT MEDIA
    2.
    发明授权
    SYSTEMS AND METHODS FOR AUTHENTICATION OF PRINT MEDIA 有权
    用于打印媒体认证的系统和方法

    公开(公告)号：EP1579622B1

    公开(公告)日：2017-12-20

    申请号：EP03790079.2

    申请日：2003-11-26

    申请人： Digimarc Corporation

    发明人： RODRIGUEZ, Tony, F. ,  REED, Alastair, M. ,  SHARMA, Ravi, K. ,  ALATTAR, Osama, M. ,  HANNIGAN, Brett, T. ,  LEVY, Kenneth, L. ,  BRUNK, Hugh, L.

    IPC分类号： H04N1/00

    CPC分类号： H04N1/00846 ,  H04N1/00002 ,  H04N1/00005 ,  H04N1/00037

    摘要： This disclosure describes methods for using embedded auxiliary signals in documents for copy detection and other applications. In an application, the auxiliary signal is formed as an array of elements selected from a set of print structures (106) with properties that change differently in response to copy operations. These changes in properties of the print structures that carry the embedded auxiliary signal are automatically detectable. The extent to which the auxiliary data is detected forms a detection metric used in combination with one or more other metrics to differentiate copies from originals. Robust and fragile watermarks are used in Image Replacement Documents for a variety of applications. Digital watermarks act as on-board mediators in authentication of a variety of printed documents. Finally, digital watermarks are used to help manage quality of the scanners used in imaging systems.

    SIGNAL PROCESSORS AND METHODS FOR ESTIMATING GEOMETRIC TRANSFORMATIONS OF IMAGES FOR DIGITAL DATA EXTRACTION
    3.
    发明公开
    SIGNAL PROCESSORS AND METHODS FOR ESTIMATING GEOMETRIC TRANSFORMATIONS OF IMAGES FOR DIGITAL DATA EXTRACTION 审中-公开
    用于估计数字数据提取的图像的几何转换的信号处理器和方法

    公开(公告)号：EP3311360A1

    公开(公告)日：2018-04-25

    申请号：EP16825285.6

    申请日：2016-07-15

    申请人： Digimarc Corporation

    发明人： SHARMA, Ravi, K. ,  LORD, John, D. ,  LYONS, Robert, G. ,  ALATTAR, Osama, M. ,  BOLES, Jacob, L.

    IPC分类号： G06T3/00 ,  G06T3/40

    CPC分类号： G06T1/0064 ,  G06K9/6206 ,  G06T3/0006 ,  G06T3/0056 ,  G06T2201/0052 ,  G06T2201/0065 ,  G06T2201/0081

    摘要： Signal processing devices and methods estimate a geometric transform of an image signal. From a seed set of transform candidates, a direct least squares method applies a seed transform candidate to a reference signal and then measures correlation between the transformed reference signal and an image signal in which the reference signal is encoded. Geometric transform candidates encompass differential scale and shear, which are useful in approximating a perspective transform. For each candidate, update coordinates of reference signal features are identified in the image signal and provided as input to a least squares method to compute an update to the transform candidate. The method iterates so long as the update of the transform provides a better correlation. At the end of the process, the method identifies a geometric transform or set of top transforms based on a further analysis of correlation, as well as other results. Phase characteristics are exploited in the process of updating coordinates and measuring correlation. The geometric transform is used as an approximation of the geometric distortion of an image after digital data is encoded in it, and is used to compensate for this distortion to facilitate extracting embedded digital messages from the image. Due to the errors in the approximation, a signal confidence metric is determined and used to weight message symbol estimates extracted from the image.