Systems, devices, and methods for proximity-based eye tracking

• US 10,241,572 B2
• Filed: 12/11/2017
• Issued: 03/26/2019
• Est. Priority Date: 01/20/2016
• Status: Active Grant

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: North Inc. (Alphabet Inc.)
• Inventors: Vidal, Melodie, Chapeskie, Jake
• Primary Examiner(s): Rayan, Mihir K
• Application Number:
  US15/837,239
• Publication Number:
  US 20180101229A1
• Time in Patent Office: 470 Days
• CPC Class Codes: G01S 17/08 for measuring distance only indirect measurement G01S17/46; active triangulation systems G01S17/48
• CPC Class Codes: G01S 17/10 using transmission of interrupted, pulse-modulated waves determination of distance by phase measurements G01S17/32
• CPC Class Codes: G01S 17/32 using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated
• CPC Class Codes: G01S 17/42 Simultaneous measurement of distance and other co-ordinates indirect measurement G01S17/46
• CPC Class Codes: G01S 17/46 Indirect determination of position data
• CPC Class Codes: G01S 17/58 Velocity or trajectory determination systems; Sense-of-movement determination systems
• CPC Class Codes: G01S 17/66 Tracking systems using electromagnetic waves other than radio waves
• CPC Class Codes: G01S 17/87 Combinations of systems using electromagnetic waves other than radio waves
• CPC Class Codes: G01S 17/88 Lidar systems specially adapted for specific applications
• CPC Class Codes: G02B 2027/014 comprising information/image processing systems
• CPC Class Codes: G02B 2027/0178 Eyeglass type eyeglass details G02C
• CPC Class Codes: G02B 27/0093 with means for monitoring data relating to the user, e.g. head-tracking, eye-tracking
• CPC Class Codes: G02B 27/0172 characterised by optical features
• CPC Class Codes: G02B 27/0176 characterised by mechanical features
• CPC Class Codes: G06F 1/163 Wearable computers, e.g. on a belt
• CPC Class Codes: G06F 3/011 Arrangements for interaction with the human body, e.g. for user immersion in virtual reality blind teaching G09B21/00
• CPC Class Codes: G06F 3/013 Eye tracking input arrangements G06F3/015 takes precedence

Abstract

Systems, devices, and methods for proximity-based eye tracking are described. A proximity sensor positioned near the eye monitors the distance to the eye, which varies depending on the position of the corneal bulge. The corneal bulge protrudes outward from the surface of the eye and so, all other things being equal, a static proximity sensor detects a shorter distance to the eye when the cornea is directed towards the proximity sensor and a longer distance to the eye when the cornea is directed away from the proximity sensor. Optical proximity sensors that operate with infrared light are used as a non-limiting example of proximity sensors. Multiple proximity sensors may be used and processed simultaneously in order to provide a more accurate/precise determination of the gaze direction of the user. Implementations in which proximity-based eye trackers are incorporated into wearable heads-up displays are described.

Claims

1. A method of determining a gaze direction of a user, the method comprising:

illuminating at least a portion of an eye of the user with infrared light by a first illumination source;

detecting reflections of infrared light from the eye of the user by a first photodetector;

determining, by a processor communicatively coupled to at least the first photodetector, a distance between the first photodetector and the eye of the user based on reflections of infrared light from the eye of the user detected by the first photodetector; and

determining, by the processor, the gaze direction of the user based on at least the distance between the first photodetector and the eye of the user, wherein determining, by the processor, the gaze direction of the user based on at least the distance between the first photodetector and the eye of the user includes determining, by the processor, that the user is gazing in a direction towards the first photodetector when the distance between the first photodetector and the eye of the user is determined to be at or near a minimum value and that the user is gazing in a direction other than towards the first photodetector when the distance between the first photodetector and the eye of the user is determined to be at or near a maximum value.

2. The method of claim 1, further comprising:

illuminating at least a portion of the eye of the user with infrared light by a second illumination source;

detecting reflections of infrared light from the eye of the user by a second photodetector, wherein the processor is communicatively coupled to the second photodetector; and

determining, by the processor, a distance between the second photodetector and the eye of the user based on reflections of infrared light from the eye of the user detected by the second photodetector, wherein determining, by the processor, the gaze direction of the user based on at least the distance between the first photodetector and the eye of the user includes determining, by the processor, the gaze direction of the user based on both the distance between the first photodetector and the eye of the user and at least the distance between the second photodetector and the eye of the user.

3. The method of claim 2, further comprising:

illuminating at least a portion of the eye of the user with infrared light by at least one additional illumination source;

detecting reflections of infrared light from the eye of the user by at least one additional second photodetector, wherein the processor is communicatively coupled to the at least one additional photodetector; and

determining, by the processor, a distance between the at least one additional photodetector and the eye of the user based on reflections of infrared light from the eye of the user detected by the at least one additional photodetector, wherein determining, by the processor, the gaze direction of the user based on both the distance between the first photodetector and the eye of the user and at least the distance between the second photodetector and the eye of the user includes determining, by the processor, the gaze direction of the user based on;

the distance between the first photodetector and the eye of the user, the distance between the second photodetector and the eye of the user, and the distance between the at least one additional photodetector and the eye of the user.

4. The method of claim 1 wherein the processor is communicatively coupled to a non-transitory processor-readable storage medium that stores data and/or instructions that, when executed by the processor, cause the processor to:

determine the distance between the first photodetector and the eye of the user based on reflections of infrared light from the eye of the user detected by the first photodetector; and

determine the gaze direction of the user based on at least the distance between the first photodetector and the eye of the user.

5. The method of claim 1 wherein determining, by a processor communicatively coupled to at least the first photodetector, a distance between the first photodetector and the eye of the user based on reflections of infrared light from the eye of the user detected by the first photodetector includes determining, by the processor, the distance between the first photodetector and the eye of the user based on at least one property selected from a group consisting of:

an intensity of reflections of infrared light from the eye of the user detected by the first photodetector, a power of reflections of infrared light from the eye of the user, a luminance of reflections of infrared light from the eye of the user, and a time of flight of reflections of infrared light from the eye of the user.