Method and apparatus for watermark detection for specific scales and arbitrary shifts
CA 2332548 C · Owner: Macrovision Corporation · Inventors: Collier, David C.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Methods and devices for detecting a watermark in a watermarked video stream the watermark having been scaled by an unknown scale among a predetermined finite number of scales and shifted by an unknown number of pixels. For each of the predetermined number of scales, the video stream is divided into a plurality of equally sized scaled watermark blocks; and the plurality of scaled watermark blocks are read into a plurality of read blocks. Each of the read blocks are accumulated into one of a predetermined number of read block bins. The accumulated read blocks are then re-scaled and combined into a single video accumulated block. A predetermined quantity such as the power of , a DCT, is …
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Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Filed February 17, 1999 and granted October 7, 2003. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended February 17, 2019.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by February 17, 2021.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
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Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.