System and method for iris data acquisition for biometric identification

• US 8,553,948 B2
• Filed: 08/29/2008
• Issued: 10/08/2013
• Est. Priority Date: 09/01/2007
• Status: Active Grant

• Current Assignee: EyeLock LLC (VOXX International Corporation)
• Original Assignee: Eyelock Corporation (VOXX International Corporation)
• Inventors: Hanna, Keith J.
• Primary Examiner(s): Park, Edward
• Application Number:
  US12/675,189
• Publication Number:
  US 20100232655A1
• Time in Patent Office: 1,866 Days
• Field of Search: 382/115, 382/117, 382/124
• US Class Current: 382/117
• CPC Class Codes: A61B 3/14 Arrangements specially adapted for eye photography apparatus or arrangements for taking photographs per se G03B
• CPC Class Codes: G06V 10/20 Image preprocessing
• CPC Class Codes: G06V 40/19 Sensors therefor
• CPC Class Codes: G06V 40/193 Preprocessing; Feature extraction

Abstract

A system and related method for acquiring high quality images of the iris of an unconstrained subject comprising a camera; a controllable focusing component; a focus controller component that controls the lens to focus at successively different points within a focus range, such focus control performed without any input from measurement of whether the image is in focus or out of focus, be it based from measurements of the image or other distance metrics to the subject; and a sharpness detection component that rejects the most out-of-focus images based on measurement of focus on the image is disclosed.

Claims

1. A system for acquiring imagery in a large capture volume, acquiring a series of images of a subject at a predetermined range of focus values, independent of feedback from a focus measurement value, the series of images including high quality images of an iris of an unconstrained subject, the system comprising:

a camera;

a lens with controllable focus;

a focus controller component comprising a processor that controls the lens to focus at a predetermined series of different points within a focus range, without any input from measurement of whether the image is in focus or out of focus, or other distance metrics to the subject; and

a sharpness and/or contrast detection component comprising a processor that rejects the most out-of-focus images based on measurement of focus on each of the acquired images.

2. The system of claim 1 configured to repeat scanning over a range of focuses until an image with the iris in sharpness exceeding a threshold is acquired.

3. The system of claim 1, wherein the sharpness and/or contrast detection component automatically determines the sharpness and/or contrast of each acquired image, and the focus controller component controls the lens to focus at different points within a focus range and to acquire an image at each of the different points within the focus range for a time period which is the lesser of a preset timeout period or until an image of an iris having a sharpness exceeding a predetermined threshold is acquired and determined.

4. The system of claim 3 comprising computer-readable memory to store only the sharpest image of the iris among the images of the iris acquired.

5. The system of claim 3, wherein the system repetitively overwrites the best stored iris image and replaces it with an image of higher calculated quality.

6. The system of claim 1, wherein the system acquires the series of images over a monotonic series of focus values within the predetermined range.

7. The system of claim 1, wherein the system acquires a focus measurement value prior to acquisition of the series of images.

8. The system of claim 1, wherein the system acquires a focus measurement value prior to acquisition of the series of images, the series of images acquired over a monotonic series of focus values within the predetermined range.

9. The system of claim 1, further comprising a processor for activating or initializing the focus controller prior to acquisition of the series of images.

10. The system of claim 1, wherein the detection component determines the sharpness or contrast of the image as the series of images is acquired.

11. The system of claim 1, wherein the system determines a focus measurement of the image, or a peak in focus measurements, as the series of images is acquired.

12. The system of claim 1, wherein the focus controller component controls the lens to focus at the predetermined series of different points within the focus range substantially according to a sawtooth scan pattern.

13. The system of claim 1, wherein the focus controller component controls the lens to sweep through a substantial portion of the focus range without discrete stops and starts.

14. The system of claim 1, wherein the system computes a value from one or more prior focus settings, and determines the series of different points within the focus range at which to acquire the images.

15. The system of claim 1, wherein the system measures a feature of the subject'"'"'s eye, determines a slice of depth volume;

identifies the focus range based on the slice of depth volume, and determines the series of different points within the focus range at which to acquire the images.

16. The system of claim 1, wherein the system measures a feature of the subject'"'"'s eye, and determines the series of different points within the focus range at which to acquire the images.

17. The system of claim 1, wherein the detection component rejects at least one of the most out-of-focus images based on a result of biometric matching.

18. The system of claim 1, wherein the focus controller component controls the lens to focus at the series of different points within the focus range according to a substantially random scan pattern.

19. A system for acquiring imagery in a large capture volume, the system configured to acquire a series of images of a subject at a predetermined range of focus values, independent of feedback from a focus measurement value, the quality of the images within the series differing, depending on factors comprising the location of the subject within the capture volume, and whether an eye of the subject is within view;

the system further configured to acquire high quality images of an iris of an unconstrained subject comprising a camera;

a lens with controllable focus;

a focus controller component comprising a processor that controls the lens to focus at a predetermined series of different points within a focus range, such focus control performed without any input from measurement of whether the image is in focus or out of focus, or other distance metrics to the subject; and

a sharpness and/or contrast detection component comprising a processor that rejects the most out-of-focus images based on measurement of focus on the image.