Method and apparatus for extracting pixel values
CA 2470346 C · Owner: British Telecommunications Public Limited Company · Inventors: Jiang, Jianmin; Xu, Li-Qun
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The invention provides a method and apparatus for extracting the luminance and chrominance values of pixels encoded according to MPEG or JPEG encoding using a forward discrete cosine transform (DCT). The invention applies theoretical work to mathematically analyse the forward DCT used in MPEG encoding to derive a set of equations which directly relate a pixel value in an encoded image to one or more of the DCT coefficients obtained via the forward DCT transform in the usual image encoding process. These predetermined equations are used in the invention to allow for extremely fast and computationally efficient extraction of pixel values directly from the DCT coefficients of an …
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 December 24, 2002 and granted May 1, 2012. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended December 24, 2022.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by December 24, 2024.
- 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.