Fingerprint sensor having filtering and power conserving features and related methods
US6067368A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 16, 1997 |
| Grant date | May 23, 2000 |
| Priority date | — |
| Expiry date | May 16, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06V40/67
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A fingerprint sensor includes an array of fingerprint sensing elements and associated active circuits and an impedance matrix filter connected to the active circuits for filtering the signals. The impedance matrix filter preferably comprises a plurality of impedance elements with a respective impedance element connectable between each the active circuit for each fingerprint sensing element and at least one other active circuit for an adjacent fingerprint sensing element. The impedance matrix filter may also include a plurality of switches with a respective switch connected in series with each impedance element. In one embodiment, the switches may be selectively operated to determine ridge flow directions of the fingerprint image. In addition, the ridge flow directions may be used to determined a core location of the fingerprint image. The switches may also be selectively operated to convert a gray scale fingerprint image to a binarized fingerprint image. Accordingly, processing of the fingerprint image may be carried out at the sensor and thereby reduce additional downstream computational requirements. In addition, sets of active circuits may be sequentially powered while the corre…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.