System for interpreting scannable marks
CA 2131222 C · Owner: Scantron Corporation · Inventors: Grundy, John N. Jr.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
To determine a read level threshold for discriminating those response bubbles on a scannable answer sheet intended to be marked from those response bubbles not intended to be marked an adjustable read level threshold is dynamically determined based on the read levels of a designated pool of response bubbles.
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 August 31, 1994 and granted December 30, 2003. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended August 31, 2014.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by August 31, 2016.
- 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.