Optical method for identifying or recognizing a pattern to be identified
US5239595A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 20, 1990 |
| Grant date | Aug 24, 1993 |
| Priority date | — |
| Expiry date | Nov 20, 2010 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06V10/88
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method of obtaining a correlation between a pattern to be identified and a number of reference patterns by irradiating and displaying the pattern to be identified and the reference patterns on an optical display plane, thereby producing a complex optical amplitude distribution. This distribution is Fourier-transformed to produce a first power spectrum corresponding to the light intensity distribution of its Fourier transformation patterns. The patterns are again irradiated based upon the first power spectrum and a second Fourier transform is performed to produce a second power spectrum which is the light intensity distribution of the second Fourier transformation pattern. The area of this distribution is restricted by controlling the transmittance or the reflectance of each of the portions of the display plane.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.