System and method for iris data acquisition for biometric identification

• US 9,095,287 B2
• Filed: 03/05/2013
• Issued: 08/04/2015
• Est. Priority Date: 09/01/2007
• Status: Expired due to Fees

• 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:
  US13/786,079
• Publication Number:
  US 20130182093A1
• Time in Patent Office: 882 Days
• Field of Search: 382/115, 382/118, 382/100, 348/78
• US Class Current: 1/1
• 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 method for acquiring imagery in a large capture volume, including a series of images of a subject at a predetermined range of focus values, independent of feedback from a focus measurement value, the method comprising:

(a) controlling, by a focus controller component, a controllable focusing component comprising a lens, to focus at a predetermined series of different values within a focus range, without any input from measurement of whether an image of an unconstrained subject to be acquired is in focus or out of focus, or other distance metrics to the subject;

(b) acquiring a plurality of images of an iris of the subject; and

(c) rejecting, by a sharpness and/or contrast detection component, a number of the most out-of-focus images based on measurement of focus on each of the acquired images.

2. The method of claim 1, further comprising scanning over a range of focus values repeatedly until an image with the iris having sharpness exceeding a threshold is acquired.

3. The method of claim 1, further comprising automatically determining at least one of the sharpness and contrast of each acquired image, controlling the lens to focus at different points within a focus range and acquiring 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 method of claim 1, wherein (c) comprises repetitively overwriting a stored iris image and replacing it with an image of higher calculated quality.

5. The method of claim 1, wherein (c) comprises acquiring the plurality of images over a monotonic series of focus values within the predetermined range.

6. The method of claim 1, wherein (c) comprises determining, by the detection component, the sharpness or contrast of each image as the plurality of images is acquired.

7. The method of claim 1, further comprising determining a focus measurement of each image, or a peak in focus measurements, as the plurality of images is acquired.

8. The method of claim 1, wherein (a) comprises controlling the lens to focus at the predetermined series of different points substantially according to one of:

a sawtooth scan pattern and a random scan pattern.

9. The method of claim 1, wherein (a) comprises controlling the lens to sweep through a substantial portion of the focus range without discrete stops and starts.

10. The method of claim 1, further comprising computing a value from one or more prior focus settings, and determining the series of different points within the focus range at which to acquire the images.

11. The method of claim 1, further comprising measuring a feature of the subject'"'"'s eye, and determining the series of different points within the focus range at which to acquire the images.

12. The method of claim 1, wherein (c) comprises rejecting at least one of the most out-of-focus images based on a result of biometric matching.

13. A system for acquiring imagery in a large capture volume, including images of an iris of an unconstrained subject, the system comprising:

a controllable focusing component comprising a lens;

a focus controller component that controls the lens to focus at a predetermined series of different points within a focus range to acquire a plurality of images, without any input from measurement of whether the image is in focus or out of focus; and

a detection component processor that rejects, based on measurement of at least one of sharpness and contrast in each of the acquired images, the most out-of-focus images.

14. The system of claim 13, wherein the focus controller component controls the lens to scan over a range of focus values repeatedly until an image with the iris having sharpness exceeding a threshold is acquired.

15. The system of claim 13, wherein the detection component processor determines the sharpness and/or contrast of each acquired image, and the lens is controlled to focus at different points within a focus range, 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.

16. The system of claim 13, wherein the system repetitively overwrites a stored iris image and replaces it with an image of higher calculated quality.

17. The system of claim 13, wherein the system acquires the plurality of images over a monotonic series of focus values within the predetermined range.

18. The system of claim 13, wherein the detection component processor determines the sharpness or contrast of each image as the plurality of images is acquired.

19. The system of claim 13, wherein the detection component processor determines a focus measurement of each image, or a peak in focus measurements, as the plurality of images is acquired.

20. The system of claim 13, wherein the focus controller component controls the lens to focus at the series of different points substantially according to one of:

a sawtooth scan pattern and a random scan pattern.

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

22. The system of claim 13, wherein the focus controller component 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.

23. The system of claim 13, wherein the detection component processor measures a feature of the subject'"'"'s eye, and the focus controller component determines the series of different points within the focus range at which to acquire the images.

24. The system of claim 13, wherein the detection component processor rejects at least one of the most out-of-focus images based on a result of biometric matching.