Robust digital watermarking
CA 2276378 C · Owner: Miller, Matthew L. · Inventors: Cox, Ingemar J.; Miller, Matthew L.; Oami, Ryoma
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A watermarking procedure that is applicable to images audio, video and multimedia data to be watermarked divides the data to be watermarked into a set of nxn blocks such as the 8x8 blocks of MPEG. The same watermark signal can be distributed throughout the set of blocks in a large variety of ways. This allows the insertion algorithm to be changed without affecting the decoders. The decoding procedure first sums together the DCT coefficients of N sets of 8x8 blocks to form a set of N summed 8x8 blocks and then extracts the watermark from the summed block. Since the sum of the DCT blocks is equal to the DCT of the sum of the intensity blocks efficient decoding can occur in both the spatial …
Read the whole patent
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 June 23, 1999 and granted February 4, 2003. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended June 23, 2019.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by June 23, 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
Timeline From CIPO dates
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.