Matcher
US4696046A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 27, 1986 |
| Grant date | Sep 22, 1987 |
| Priority date | — |
| Expiry date | Mar 27, 2006 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06V40/12
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A set of Search identification points derived from an optical scan of a finger are compared against File identification points for the same finger. A multiple comparator divides the finger image into multiple segments. The Search and File points from each segment are compared separately. A difference table (D.T.) provides a proximity value Q for each search point. The D.T. is purged of all entries representing multiple Search points. The purge keeps those entries having the highest Q value. The purged D.T. with recalculated Q values is the basis for correcting the position of each Search point on the image plane to compensate for shift in finger position and for the variable distortion and changes that come about in a finger over time and upon successive applications of the finger to input scan. The corrected Search points are compared against the File points to establish a new D.T. A proximity value Q for each entry on this D.T. is calculated and a proximity value Q for the entire table is calculated. These proximity values in view of the number of entries on the difference table are used to verify identification in a scoring routine.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.