Estimating the difference in picture quality between two versions of a video signal
CA 2262822 A1 · Owner: Nds Limited · Inventors: Bock, Alois Martin
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The invention relates to estimating the difference in picture quality between two versions of a video signal, one of which has been subject to distortion and, the other of which has not been subject to the distortion. The invention has application to estimating the picture quality of a signal subjected to digital compression in comparison to the picture quality of the signal before compression. The estimate of picture quality is obtained by first deriving a difference signal, representing the difference between the distorted and undistorted versions of the video signal. A masking signal is obtained by filtering the undistorted version of the video signal and is used to mask the difference …
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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 24, 1999. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended February 24, 2019.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by February 24, 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.