Finger surface image enhancement having a liquid layer on the finger touching surface of the platen
US5051576A · kind A · utility
12Cited by
11References
12Claims
0Family size
Inventor
Key dates
| Filing date | Jul 31, 1990 |
| Grant date | Sep 24, 1991 |
| Priority date | — |
| Expiry date | Jul 31, 2010 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61B5/1172
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
A layer of liquid, such as water, on the finger touching surface of a platen provides an image in a optical fingerprint imaging system which assures valley and ridge definition and continuity by virture of the water filling in the cracks and holes in the ridge zone and by creating an air pocket in the valley zone that holds the valleys open. Multiple interrogating light beams, each incident at greater than the critical angle on the finger touching surface of the platen assure imaging all minutia and that the valley zones in the image will be black.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.