METHOD AND SYSTEM FOR IRIS IMAGE CAPTURE

• US 20110304721A1
• Filed: 06/09/2010
• Published: 12/15/2011
• Est. Priority Date: 06/09/2010
• Status: Active Grant

• Current Assignee: Gentex Corporation
• Original Assignee: Honeywell International Inc.
• Inventors: Determan, Gary Edward, Jelinek, Jan
• Granted Patent: US 8,957,956 B2
• Time in Patent Office: Days
• US Class Current: 348/78
• CPC Class Codes: H04N 23/676 Bracketing for image capture at varying focusing conditions

Abstract

According to one example embodiment, a process and system include a camera used to capture a sequence of illuminated images of an subject, wherein the images are stored in frames. The focus point is changed for each image captured so that the focus point sweeps from a far to a near end of a sweep range, in discrete steps or continuous motion, so that successive images have slightly overlapping depths of field. The sweep range and overlapping depths of field provide that at least one image is well focused on the iris of the eye of the subject. In one other example embodiment, one or more of the images are illumined with a illumination fired for a respective captured image. In another embodiment, the sweep range is determined at least in part using a range finder or is otherwise controlled to determine a position of the subject so that the sweep range starts and stops a desired distance in front of and behind the subject, respectively.

Claims

1. A process comprising:

using a camera to capture a sequence of illuminated images of an subject, wherein the images are stored in frames;

dynamically changing the focus point for each image captured so that the focus point sweeps from a far to a near end of a sweep range so that successive images have overlapping depths of field; and

wherein the sweep range and overlapping depths of field provide that at least one image is focused on the iris of the eye of the subject.

2. A process according to claim 1 further including illuminating one or more of the images with an illumination fired for a respective captured image.

3. A process according to claim 1 wherein the focus point sweeps in discrete steps or continuously across the sweep range.

4. A process according to claim 2 wherein a camera shutter is synchronized with the illuminations.

5. A process according to claim 1 wherein the sweep range is determined at least in part using a range finder to determine a position of the subject so that the sweep range starts and stops a desired distance in front of and behind the subject or a feature or body part of the subject, respectively.

6. A system comprising:

a camera and a lens;

a control system to produce control signals to control the image exposure and lens so that the camera captures a sequence of images of an subject, wherein the images are stored in frames and further wherein the focus point for each image is captured so that the focus point sweeps from a far to a near end of a sweep range and so that successive images have overlapping depths of field; and

wherein the sweep range and overlapping depths of field provide that at least one image is focused on the iris of the eye of the subject.

7. A system according to claim 6 further including an illumination device to produce a illumination to illuminate one or more of the images, and further wherein the control system produces a signal to control the illumination device to produce the illumination synchronously with the one or more exposures.

8. A system according to claim 6 wherein the control system produces a control system to control the lens to change the focus point in discrete steps or continuously across the sweep range.

9. A system according to claim 6 further including a range finder and wherein the control systems further receives one or more signals from the range finder to indicate a distance from the camera of the subject or a feature or part of a subject within the operating range of the system, and further wherein the sweep range starts and stops a desired distance in front of and behind the subject or a feature or body part of the subject, respectively.

10. A system according to claim 6 further wherein the control system comprises a computing system including a non-transitory computer program that configures the computing system to cause the control system to produce the control signals.

11. A system according to claim 10 further wherein the control system includes at least one input/output system to produce the control signals or receive signals.

12. A system comprising:

a camera and a lens;

an illumination device comprising one or more illuminators;

a control system to produce control signals to control the image exposure, illumination device and lens so that the camera captures a sequence of images of an subject, wherein the images are stored in frames and further wherein the focus point for each image is captured so that the focus point sweeps from a far to a near end of a sweep range and so that successive images have overlapping depths of field;

wherein the sweep range and overlapping depths of field provide that at least one image is focused on the iris of the eye of the subject;

at least one database of iris feature information for a plurality of subjects stored in a memory and/or storage device of a computing system;

at least one computer program executing on the computing system to identify the subject for whom the iris image has been obtained by reference to the iris feature information in the database.