Apparatus and method for determining the location and orientation of a reference feature in an image
US6240218A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 14, 1995 |
| Grant date | May 29, 2001 |
| Priority date | — |
| Expiry date | Mar 14, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06V10/7515
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method and apparatus for determining the location and orientation of a reference feature in an image is provided. At train-time, a template image is created for use during the run-time phase. At run-time, a reference feature is located by first determining the principal angle of the reference feature. In a preferred embodiment, the principal angle .theta. of the reference feature is found by partitioning the reference feature into a plurality of regions, projecting each of the regions at 0.degree., and performing template matching with a template image to determine the position of a plurality of points along a principal axis of the reference feature. Then, either an equation of a "best fit" line can be calculated and solved simultaneously with an equation of a horizontal reference line, or the reference feature image can be projected at the angle of the "best fit" line to obtain a one-dimensional reference image which can be matched to the one-dimensional template image to find the relative displacement between them that maximizes a match-metric value. The invention is particularly useful for determining the location and orientation of reference feature images that have been degr…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.