A ballot or sheet having an anti-copying feature provides for detecting from an image of the ballot or sheet whether the ballot or sheet is an original or is a copy. The anti-copying feature may lighten or darken, or both, when copied and may or may not be evident to the human eye. A reader comprising...http://www.google.fr/patents/US20090289115?utm_source=gb-gplus-shareBrevet US20090289115 - OPTICALLY READABLE MARKING SHEET AND READING APPARATUS AND METHOD THEREFOR
OPTICALLY READABLE MARKING SHEET AND READING APPARATUS AND METHOD THEREFOR
Numéro de demande: 12/207,096 Numéro de publication: US 2009/0289115 A1 Date de dépôt: 9 sept. 2008 Brevet délivré: US8066184 ( Date de délivrance 29 nov. 2011)
