Apparatus and method of attenuating distortion introduced by a predictive coding image compressor
CA 1325672 C · Owner: Pennebaker, William B. · Inventors: Pennebaker, William B.; Gonzales, Cesar A.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The present invention relates to a predictive coding method and related apparatus which (a) computes a value D representing the difference between an original graylevel value for a current pixel and a predicted value for the current pixel; (b) associates each successive range of D values to a respective quantization level, each quantization level QN having a respective QN value representing the range corresponding thereto; (c) sets a respective QERR value to D for the current pixel, when the QN value is zero; (d) re-maps m QERR values to n (n ? m) MERR values; (e) assigns to the value MERR=0 those QERR values in which ?QERR??(+Q1VALUE)/2 sums the MERR values for successive pixels in a QN=Q0 …
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
- Granted December 28, 1993. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended December 28, 2010.
- 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.