Method and apparatus for optical pattern recognition
US5619596A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Oct 6, 1993 |
| Grant date | Apr 8, 1997 |
| Priority date | — |
| Expiry date | Oct 6, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06V10/92
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An object of the invention is to provide a method and a apparatus for optical pattern recognition capable of accurately comparing and identifying a reference image accurately at a real-time even when the input image rotates or its size changes by being compared with a reference image that is a desirous target. The method and apparatus comprise the processes of; steps (6, 11) for independently obtaining a lower-frequency component and a higher-frequency component from a joint Fourier transform image 5 of the reference image 4 and the input image 3; steps (10, 15) for calculating correlation coefficients respectively from the lower-frequency component and the higher-frequency component; step (16) for obtaining a ratio of the respective correlation coefficients; and step (19) for identifying and comparing a correlation coefficient ratio of the two same reference images to be required with a correlation coefficient ratio obtained from step (16).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.