The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 08, 2003
Filed:
Mar. 02, 1999
Keith Lucas, New Market, CA;
William Van Rassel, Thorn Hill, CA;
Leitch Technology International Inc., Toronto, CA;
Abstract
Watermark data consisting of known two-dimensional codeword patterns are added to a first portion of each video frame by modifying parameters defining the first portion. Limited randomization of the spatial position of the codeword pattern is also provided. During a decoding process, a predictor continuously estimates the current value of the modified parameters. In one embodiment of the present invention, the predictor employs video samples taken from unmodified areas of the frame to provide the estimates. The estimated parameter values are subtracted from the actual parameter values to provide an error signal. Multiple correlators attempt to detect the presence of the codeword pattern in the error signal within a range of spatial locations surrounding a nominal position of the codeword pattern. The use of multiple correlators provides immunity to feasible attacks aimed at damaging or obscuring the watermark.