Method and apparatus for automatic extraction of fingerprint cores and tri-radii
US4156230A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 2, 1977 |
| Grant date | May 22, 1979 |
| Priority date | — |
| Expiry date | Nov 2, 1997 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06V40/1359
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method and apparatus for the smoothing and singularity detection of the ridge contour data of a fingerprint image for classification in an automatic fingerprint identification system. A template scanning window is passed electronically over a digital matrix of ridge contour data to generate a set of correlation values corresponding to each contour data element and to a plurality of reference angle vectors. The correlation values are processed for determination of peaks and valleys. Tests are conducted to determine whether the relative values of peaks and valleys and the relative spacing between peaks and valleys satisfy certain threshold criteria for reliable extraction of fingerprint singularity points for classification. The resultant data, representing the number of correlation peaks and the direction of each, defines the location and angular orientation of cores and deltas of a fingerprint.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.