Patents by Inventor Christianus W. F. Vriens

Christianus W. F. Vriens has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Method and arrangement for detecting a watermark
    Publication number: 20020168088
    Abstract: Recently developed methods for copy protection rely on a watermark detector to judge whether multimedia content can be copied or not. In such copy protection schemes, a watermark detector examines the multimedia content and outputs a signal (D) indicating whether a watermark is present or not. Known watermark detectors determine a decision variable (y) indicating to which extent the watermark is present, for example, the amount of correlation between the input signal and a reference copy of the watermark to be detected. The watermark is detected if the decision variable exceeds a predetermined threshold (y2). Such a detector is vulnerable to an attack which is described in this patent application.
    Type: Application
    Filed: May 9, 2002
    Publication date: November 14, 2002
    Applicant: Koninklijke Philips Electronics N.V.
    Inventors: Johan P.M.G. Linnartz, Maurice J.J.J-B. Maes, Antonius A.C.M. Kalker, Geert F.G. Depovere, Peter M.J. Rongen, Christianus W.F. Vriens, Marten E. Van Dijk
  • Device for optically scanning a record carrier
    Patent number: 6415040
    Abstract: A watermark detector is disclosed to judge whether multimedia content can be copied or not. The watermark detector examines the multimedia content and outputs a signal indicating whether a watermark is present or not. A decision variable indicating to which extent the watermark is present is determined, for example, the amount of correlation between the input signal and a reference copy of the watermark to be detected. The watermark is detected if the decision variable exceeds a predetermined threshold (y2). The detector also generates a random output signal for a predetermined range of decision values between the threshold (y2) and a further threshold (y1).
    Type: Grant
    Filed: May 20, 1998
    Date of Patent: July 2, 2002
    Assignee: Koninklijke Philips Electronics N.V.
    Inventors: Johan P. M. G. Linnartz, Maurice J. J. J-B. Maes, Antonius A. C. M. Kalker, Geert F. G. Depovere, Peter M. J. Rongen, Christianus W. F. Vriens, Marten E. Van Dijk