Method and apparatus for robustly collecting facial, ocular, and iris images using a single sensor

• US 9,373,023 B2
• Filed: 02/22/2012
• Issued: 06/21/2016
• Est. Priority Date: 02/22/2012
• Status: Expired due to Fees

• Current Assignee: SRI International, Inc.
• Original Assignee: SRI International, Inc.
• Inventors: Stoker, David
• Primary Examiner(s): Perungavoor, Sath V
• Assistant Examiner(s): Le, Peter D
• Application Number:
  US13/402,038
• Publication Number:
  US 20130215228A1
• Time in Patent Office: 1,581 Days
• US Class Current: 1/1
• CPC Class Codes: G06T 2200/28 involving image processing hardware
• CPC Class Codes: G06T 2207/10028 Range image; Depth image; 3D point clouds
• CPC Class Codes: G06T 2207/20221 Image fusion; Image merging
• CPC Class Codes: G06T 3/4053 based on super-resolution, i.e. the output image resolution being higher than the sensor resolution
• CPC Class Codes: G06T 5/50 using two or more images, e.g. averaging or subtraction
• CPC Class Codes: G06T 5/70 Denoising; Smoothing
• CPC Class Codes: G06T 7/11 Region-based segmentation
• CPC Class Codes: G06V 40/166 using acquisition arrangements
• CPC Class Codes: G06V 40/168 Feature extraction; Face representation
• CPC Class Codes: G06V 40/19 Sensors therefor
• CPC Class Codes: G06V 40/193 Preprocessing; Feature extraction
• CPC Class Codes: H04N 13/204 using stereoscopic image cameras stereoscopic photography G03B35/00
• CPC Class Codes: H04N 13/239 using two 2D image sensors having a relative position equal to or related to the interocular distance H04N13/243 takes precedence

Abstract

The present invention relates to a method and apparatus for standoff facial and ocular acquisition. Embodiments of the invention address the problems of atmospheric turbulence, defocus, and field of view in a way that minimizes the need for additional hardware. One embodiment of a system for acquiring an image of a facial feature of a subject includes a single wide field of view sensor configured to acquire a plurality of images over a large depth of field containing the subject and a post processor coupled to the single sensor and configured to synthesize the image of the facial feature from the plurality of images.

Claims

1. A system for acquiring an enhanced resolution image from a plurality of received telescopic low resolution images of a facial feature of a subject in a field of view, the system comprising:

a memory comprising instructions that when executed by a hardware processor of the system implement a subject tracker, the subject tracker configured to track the subject;

a single sensor coupled to the subject tracker and configured to acquire a burst of the plurality of received telescopic low resolution images of a depth of field in the field of view and containing the subject in response to determining, by the subject tracker, that the subject tracker has entered the field of view; and

a post processor coupled to the single sensor, the post processor configured to track the facial feature through the plurality of received telescopic images and to create the enhanced resolution image of the facial feature from the plurality of received telescopic low resolution images by enhancing at least the depth of field and the field of view by selecting a range of sequential low-resolution images of the plurality of received telescopic low resolution images based on the subject being within a threshold of focal quality and fusing the selected range of images.

2. The system of claim 1, wherein the single sensor is low resolution and the enhanced resolution image is of high resolution.

3. The system of claim 1, wherein the single sensor is an only imaging sensor included in the system.

4. The system of claim 1, wherein a field of view of the single sensor is at least ten inches by ten inches.

5. The system of claim 4, wherein the field of view is covered by no less than one thousand pixels by one thousand pixels.

6. The system of claim 1, wherein the single sensor operates at a frame rate of greater than several hundred Hertz.

7. A method for acquiring an image of a facial feature of a subject in a telescopic field of view, the method comprising:

acquiring a plurality of telescopic low resolution images of a depth of field containing the subject by at least tracking the facial feature through the plurality of images;

selecting a range of sequential low-resolution images of the plurality of images based on the subject being within a threshold of focal quality; and

synthesizing the image of the facial feature from the selected range of images by enhancing at least the depth of field and the field of view.

8. The method of claim 7, wherein a resolution of the plurality of images is less than a resolution of the image of the facial feature.

9. The method of claim 7, wherein the acquiring comprises sweeping a focus of a single sensor over the depth of field.

10. The method of claim 7, wherein the acquiring is performed at a frame rate of at least several hundred Hertz.

11. The method of claim 7, wherein the synthesizing comprises image region segmentation and fusion to extend the depth of field in a super-resolved version of the image of the facial feature relative to individual depths of field in the plurality of images.

12. The method of claim 7, wherein the synthesizing comprises mitigating turbulence in the plurality of images.

13. The method of claim 7, wherein the synthesizing comprises denoising the plurality of images.

14. The method of claim 7, wherein the acquiring comprises:

saving the plurality of images as a burst of images having a low resolution relative to the image of the facial feature that is synthesized from the plurality of images.

15. The method of claim 14, wherein the saving is triggered by a gaze detection technique operating in conjunction with a facial detection technique.

16. The method of claim 7, wherein the acquiring is performed using a Vertical Cavity Surface Emitting Laser illumination source.

17. The method of claim 7, wherein the acquiring comprises:

determining an approximate angular location and range of the subject containing biometric features.

18. The method of claim 17, wherein the determining is performed using a passive scene monitor based on a stereo camera.

19. A non-transitory computer readable storage medium containing an executable program for acquiring an image of a facial feature of a subject in a telescopic field of view, where the program performs steps comprising:

acquiring a plurality of telescopic low resolution images of a depth of field containing the subject;

selecting a range of sequential low-resolution images of the plurality of images based on the subject being within a threshold of focal quality; and

synthesizing the tracked image of the facial feature from the selected range of images by enhancing at least the depth of field and the field of view.

20. The computer readable storage medium of claim 19, wherein a resolution of the plurality of images is less than a resolution of the image of the facial feature.