Position, rotation, and intensity invariant recognizing method
US4838644A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 15, 1987 |
| Grant date | Jun 13, 1989 |
| Priority date | — |
| Expiry date | Sep 15, 2007 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S359/90
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method for recognizing the presence of a particular target in a field of view which is target position, rotation, and intensity invariant includes the preparing of a target-specific invariant filter from a combination of all eigen-modes of a pattern of the particular target. Coherent radiation from the field of view is then imaged into an optical correlator in which the invariant filter is located. The invariant filter is rotated in the frequency plane of the optical correlator in order to produce a constant-amplitude rotational response in a correlation output plane when the particular target is present in the field of view. Any constant response is thus detected in the output The U.S. Government has rights in this invention pursuant to Contract No. DE-AC04-76DP00789 between the U.S. Department of Energy and AT&T Technologies, Inc.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.