Large depth-of-field imaging system and iris recogniton system
US8594388B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Feb 29, 2008 |
| Grant date | Nov 26, 2013 |
| Priority date | — |
| Expiry date | Apr 10, 2030 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06V40/19
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
(A2) An extended depth of field (DOF) imaging system (10) is disclosed that has a corresponding extended depth of focus (DOF′) by virtue of its optical system (20) having a select amount of spherical aberration. The imaging system has an image processing unit (54) adapted to process the raw images and perform contrast enhancement to form processed images. The image processing includes restoring the defocused modulation transfer functions (MTFs) using a gain function (G) and the amount of defocus. The imaging system can include an illumination system (60) that illuminates the object being imaged to establish a distance (DH) between the optical system and the object, where distance DH is used in the restoring of the MTF. An iris-recognition (I-R) system based on the enhanced DOF imaging system is also disclosed.; Optical system embodiments for use in the DOF imaging system that can provide select amounts of spherical aberration—and thus select increases in DOF—without increasing the adverse impact of other aberrations on image formation are also disclosed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.