Facial recognition

• US 8,396,265 B1
• Filed: 06/26/2012
• Issued: 03/12/2013
• Est. Priority Date: 06/26/2012
• Status: Active Grant

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: Google Inc. (Alphabet Inc.)
• Inventors: Nechyba, Michael Christian, Ross, Steven James, Schneiderman, Henry Will, Zhao, Yong
• Primary Examiner(s): PATEL, KANJIBHAI B
• Application Number:
  US13/533,682
• Time in Patent Office: 259 Days
• Field of Search: 382/103, 382/106, 382115-118, 382/128, 382/173, 382/305, 382/312, 340/5.2
• US Class Current: 382/118
• CPC Class Codes: G06F 21/32 using biometric data, e.g. fingerprints, iris scans or voiceprints
• CPC Class Codes: G06V 20/653 by matching three-dimensional models, e.g. conformal mapping of Riemann surfaces
• CPC Class Codes: G06V 40/16 Human faces, e.g. facial parts, sketches or expressions
• CPC Class Codes: G06V 40/172 Classification, e.g. identification
• CPC Class Codes: G06V 40/40 Spoof detection, e.g. liveness detection

Abstract

An example method includes capturing, by an image capture device of a computing device, an image of a face of a user. The method further includes detecting, by the computing device, whether a distance between the computing device and an object represented by at least a portion of the image is less than a threshold distance, and, when the detected distance is less than a threshold distance, denying authentication to the user with respect to accessing one or more functionalities controlled by the computing device, where the authentication is denied independent of performing facial recognition based at least in part on the captured image.

Claims

1. A method comprising:

capturing, by an image capture device coupled to a computing device, an image of a face of a user;

detecting, by the computing device, whether a distance between the image capture device and an object represented by at least a portion of the image is less than a threshold distance; and

when the detected distance is less than the threshold distance, denying authentication of the user with respect to accessing one or more functionalities controlled by the computing device, wherein the authentication is denied independent of performing facial recognition based at least in part on the captured image.

2. The method of claim 1, wherein detecting whether the distance is less than the threshold distance further comprises:

identifying at least two landmarks within the image;

determining a number of pixels of the image disposed between the at least two landmarks of a face represented in the image.

3. The method of claim 2, wherein the at least two landmarks include a left cornea and a right cornea of a face represented in the image.

4. The method of claim 2, wherein the at least two landmarks include an ocular center and a nasal base of a face represented in the image.

5. The method of claim 1, wherein detecting whether the distance between the computing device and the object represented by at least a portion of the image is less than the threshold distance further comprises measuring the distance between the computing device and the object, and wherein measuring the distance further comprises:

transmitting a light beam towards the object;

receiving a reflection associated with the transmitted light beam; and

determining the distance based at least in part on the received reflection.

6. The method of claim 5, wherein determining the distance based at least in part on the received reflection further comprises:

measuring a phase shift associated with the received reflection.

7. The method of claim 5, wherein determining the distance based at least in part on the received reflection further comprises measuring a time of flight associated with the transmitted light beam and the received reflection.

8. The method of claim 5, further comprising:

determining a reflectance associated with the transmitted light beam; and

determining the distance based at least in part on the determined reflectance.

9. The method of claim 1, further comprising:

estimating a distance between the computing device and the object represented by at least the portion of the image to obtain an estimated distance;

calculating a ratio between the detected distance and the estimated distance;

generating an acceptable margin of error based at least in part on the calculated ratio;

when the detected distance is within the margin of error from the estimated distance, processing the image to determine whether the image matches at least one of (1) an enrollment image that represents, at least in part, a face of an authorized user, and (2) a mathematical representation of the face of the authorized user.

10. The method of claim 9, further comprising:

upon determining that the image matches the enrollment image, granting authentication of the user.

11. The method of claim 1, further comprising:

upon denying authentication of the user, preventing the computing device from transitioning from a locked state to an unlocked state.

12. The method of claim 1, further comprising:

upon denying authentication of the user, denying a device communicatively coupled to the computing device permission to transition from a locked state to an unlocked state.

13. The method of claim 12, wherein the device communicatively coupled to the computing device is a door lock.

14. The method of claim 1, further comprising:

defining an acceptable distance range having a lower bound and an upper bound, wherein the lower bound corresponds to the threshold distance; and

when the detected distance is less than the lower bound or greater than the upper bound, denying authentication of the user with respect to accessing one or more functionalities controlled by the computing device, wherein the authentication is denied independent of performing facial recognition based at least in part on the captured image.

15. The method of claim 1, wherein detecting whether the distance between the computing device and the object is below the threshold distance further comprises measuring the distance by at least one of an optical proximity sensor, infrared proximity sensor, laser rangefinder, magnetic sensor, and sonar sensor.

16. The method of claim 1, further comprising:

when the distance is equal to or greater than the threshold distance, proceeding to perform a facial recognition authentication operation using the captured image.

17. The method of claim 1, further comprising:

outputting, by a display device of the computing device, a notification that indicates the denying of authentication of the user with respect to accessing one or more functionalities controlled by the computing device, wherein the authentication is denied independent of performing facial recognition based at least in part on the captured image.

18. The method of claim 1, wherein denying authentication further comprises denying authentication of the user prior to performing facial recognition based at least in part on the captured image.

19. The method of claim 1, wherein denying authentication further comprises denying authentication of the user concurrently with performing facial recognition based at least in part on the captured image.

20. The method of claim 1, wherein denying authentication of the user further comprises denying authentication of the user after performing facial recognition based at least in part on the captured image and irrespective of one or more results of performing the facial recognition.

21. A computing device comprising:

at least one processor; and

at least one image capture device,

wherein the at least one image capture device is operable to capture an image of a face of a user, and

wherein the at least one processor is configured to;

detect whether a distance between the computing device and an object represented by at least a portion of the image is less than a threshold distance; and

when the detected distance is less than a threshold distance, deny authentication of the user with respect to accessing one or more functionalities controlled by the computing device, independent of performing facial recognition based at least in part on the captured image.

22. The computing device of claim 21, wherein the at least one processor is further configured to detect whether the distance between the computing device and the object represented by at least the portion of the image is less than the threshold distance at least in part by:

identifying at least two landmarks within the image; and

determining a number of pixels of the image disposed between the at least two landmarks of a face represented in the image.

23. The computing device of claim 21, wherein the at least one processor is further configured to:

estimate a distance between the computing device and the object represented by at least the portion of the image to obtain an estimated distance;

calculate a ratio between the detected distance and the estimated distance;

generate an acceptable margin of error based at least in part on the calculated ratio; and

responsive to the detected distance being within the margin of error from the estimated distance, processing the image to determine whether the image matches at least one of (1) an enrollment image that represents, at least in part, a face of an authorized user, and (2) a mathematical representation of the face of the authorized user.

24. The computing device of claim 21, wherein the at least one processor is further configured to:

upon denying authentication of the user, prevent the computing device from transitioning from a locked state to an unlocked state.

25. The computing device of claim 21, wherein the at least one processor is further configured to:

define an acceptable distance range having a lower bound and an upper bound, wherein the lower bound corresponds to the threshold distance; and

responsive to the detected distance being less than the lower bound or greater than the upper bound, deny authentication of the user with respect to accessing one or more functionalities controlled by the computing device, wherein the authentication is denied independent of performing facial recognition based at least in part on the captured image.

26. The computing device of claim 21, further comprising at least one of an optical proximity sensor, an infrared proximity sensor, a laser rangefinder, a magnetic sensor, and a sonar sensor, wherein the at least one processor is further configured to:

detect whether the distance between the computing device and the object is below the threshold distance at least in part by measuring the distance using at least one of the optical proximity sensor, the infrared proximity sensor, the laser rangefinder, the magnetic sensor, and the sonar sensor.

27. The computing device of claim 21, wherein the at least one processor is further configured to:

responsive to the distance being equal to or greater than the threshold distance, proceed to perform a facial recognition authentication operation using the captured image.

28. The computing device of claim 21, further comprising a display device, wherein the at least one processor is further configured to:

output, for display at the display device, a notification that indicates the denying of authentication of the user with respect to accessing one or more functionalities controlled by the computing device, wherein the authentication is denied independent of performing facial recognition based at least in part on the captured image.

29. The computing device of claim 21, wherein the at least one processor is configured to detect whether the distance between the computing device and the object represented by at least a portion of the image is less than the threshold distance at least in part by measuring the distance between the computing device, and wherein the at least one processor is configured to measure the distance at least in part by:

transmitting a light beam towards the object;

receiving a reflection associated with the transmitted light beam; and

determining the distance based at least in part on the received reflection.

30. A method comprising:

capturing, by an image capture device coupled to a computing device, an enrollment image associated with an authorized user of the computing device;

detecting, by the computing device, an estimated distance between the computing device and an object represented by at least a portion of the enrollment image;

measuring, by the computing device, a first measured distance between the computing device and the object represented by at least the portion of the enrollment image;

generating, by the computing device, a correction factor at least in part by dividing the first measured distance by the estimated distance;

capturing, by the image capture device of the computing device, an authentication image;

measuring, by the computing device, a second measured distance between the computing device and an object represented by at least a portion of the authentication image;

dividing the second measured distance by the correction factor to obtain an expected actual distance;

detecting an actual distance;

determining whether the actual distance matches the expected actual distance; and

when the actual distance does not match the expected actual distance, denying authentication to a user with respect to accessing one or more functionalities controlled by the computing device, wherein the authentication is denied independent of performing facial recognition based at least in part on the authentication image and the enrollment image.