Patents Represented by Attorney, Agent or Law Firm William V. Conwell
  • Digital watermark decoding method
    Patent number: 6700990
    Abstract: To decode a digital watermark from an image notwithstanding geometrical corruption of the image (e.g., scale, rotation, etc.), a Fourier-Mellin transform is advantageously used. In a particular method, an image is transformed to the spatial frequency domain. Transformed components of the image are then pattern-matched to reference frequencies, and the thus-altered image components are transformed back to the spatial image domain to effect registration of the image prior to watermark decoding.
    Type: Grant
    Filed: September 29, 1999
    Date of Patent: March 2, 2004
    Assignee: Digimarc Corporation
    Inventor: Geoffrey B. Rhoads
  • Method and system for encoding image and audio content
    Patent number: 6647129
    Abstract: Image or audio content data is encoded to steganographically convey plural bit auxiliary data. The content data is thereafter subjected to lossy compression/decompression, and the auxiliary data can still be recovered and used, e.g., to control associated audio or video equipment.
    Type: Grant
    Filed: May 8, 2002
    Date of Patent: November 11, 2003
    Assignee: Digimarc Corporation
    Inventor: Geoffrey B. Rhoads