Image comparison system
US4513441A · kind A · utility
32Cited by
5References
16Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Aug 2, 1983 |
| Grant date | Apr 23, 1985 |
| Priority date | — |
| Expiry date | Aug 2, 2003 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N21/95607
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Image comparison is accomplished by forming a composite image composed of a reference image and a test image. A two-dimensional image spectrum is generated from the composite image and then is whitened by setting the magnitude of every point of the two-dimensional image spectrum to a uniform level. A phase-only image of the composite image is then constructed, and values of the phase-only image exceeding a predetermined threshold are detected as an indication of the location of a difference between the reference and test images.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.