Fingerprint image refinement
US4569080A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 23, 1983 |
| Grant date | Feb 4, 1986 |
| Priority date | — |
| Expiry date | Jun 23, 2003 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06V40/13
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
In an optical fingerprint image processing apparatus a light beam is scanned across a finger placed against a transparent platen in order to provide a reflected modulated light beam carrying fingerprint information. The modulated light beam is imaged and the image is intercepted by an array of photo receptors that detect the image and convert the optical signal into electrical signals. The improvement is in placing a diffuser element, which may be a ground glass wafer, in the interrogating light beam. The diffusion of the light beam acts as an effective filter to eliminate the higher spatial frequency components of the optical image and thus provide a fingerprint image having improved continuity.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.