Method and apparatus for locating an acquisition target in two-dimensional images by detecting symmetry in two different directions
US5515447A · kind A · utility
47Cited by
28References
29Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jun 7, 1994 |
| Grant date | May 7, 1996 |
| Priority date | — |
| Expiry date | Jun 7, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06K7/1456
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A system and method are disclosed for locating an acquisition target consisting of a plurality of concentric rings of alternating levels of reflectivity (bull's-eye pattern) in two-dimensional images such as optically encoded symbologies. Such targets may be found even if they vary in size and tilt angle with respect to an imaging camera. Symmetry characteristics of the targets are used to locate the targets independent of the threshold level selected for determining transitions between rings of different reflectivity.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.