Method for the insertion of guilloche patterns, method for the extraction of guilloche patterns, method for the authentication of these guilloche patterns and devices for implementation
US11065905B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 25, 2018 |
| Grant date | Jul 20, 2021 |
| Priority date | — |
| Expiry date | Sep 25, 2038 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB42D25/309
- WIPO fieldOther consumer goods
- WIPO sectorOther fields
Abstract
A method of inserting guilloche patterns in a document, each guilloche pattern being capable of encoding variable alphanumeric data ensuring a different aspect at each guilloche pattern so as to render said document secure using an operation of determining an insertion intensity of each guilloche pattern previously generated on the basis of a mid-gray level of the document near said guilloche pattern. A device for implementing this insertion method. The method further provides for extracting guilloche patterns from a secure document likely to be degraded by determining a contrast card of at least one portion of the secure document that includes the guilloche patterns, identifying, on this contrast card an optimal percolation trajectory, and extracting the optimal percolation trajectory, said trajectory corresponding to the guilloche pattern. The method further provides for authentication of the guilloche patterns of a secure document likely to be degraded, by the extraction operations, and comparing each extracted guilloche pattern with a corresponding theoretical guilloche pattern.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.