Data carrier
US7377444B2 · kind B2 · utility
2Cited by
3References
24Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Aug 1, 2003 |
| Grant date | May 27, 2008 |
| Priority date | — |
| Expiry date | Feb 9, 2024 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB42D2035/26
- WIPO fieldOther consumer goods
- WIPO sectorOther fields
Abstract
A halftone image original is converted into a line screen halftone image including regularly spaced-apart screen lines 5 that are modulated in their width y in accordance with the tonal value to be represented. According to the invention, width y of screen lines 5 is modulated only on one side so that screen lines 5 are flat on one side and width-modulated on one side. Various examples are stated for how this screen line modulation permits effective copy protection.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.