Bright pupil eye-tracking system

Patent metadata

Field	Value
Publication number	US-11867900-B2
Application number	US-202016844890-A
Country	US
Kind code	B2
Filing date	Apr 9, 2020
Priority date	Feb 28, 2020
Publication date	Jan 9, 2024
Grant date	Jan 9, 2024

Abstract

An eye-tracking method includes enabling at least one light source of an array of light sources to emit non-visible light to illuminate an eye. The method also includes obtaining at least one image of the eye while the at least one light source is enabled. A position of the eye may then be determined based on a position of the at least one light source within the array of light sources in response to determining that the at least one image indicates a bright pupil condition when the at least one light source was enabled.

First claim

What is claimed is:

1. An eye-tracking method, comprising:
enabling at least one light source of an array of light sources to emit non-visible light that propagates through an optical combiner to an eyeward side of an eye-tracking system to illuminate an eye, wherein the optical combiner is configured as a holographic optical element or a volume hologram to direct reflected non-visible light that is reflected by the eye to a camera disposed on the eyeward side of the eye-tracking system, and wherein the optical combiner is positioned on an optical axis between each light source of the array of light sources and the eye;
obtaining at least one image of the eye with the camera while the at least one light source is enabled; and
determining a position of the eye based on a position of the at least one light source within the array of light sources in response to determining that the at least one image indicates a bright pupil condition when the at least one light source was enabled.

2. The eye-tracking method of claim 1 , where determining that the at least one image indicates the bright pupil condition comprises:
comparing a brightness of the pupil in the at least one image with a brightness of the pupil in another image that corresponds to when another light source of the array of light sources is enabled to emit non-visible light to illuminate the eye.

3. The eye-tracking method of claim 1 , wherein determining that the at least one image indicates the bright pupil condition comprises:
comparing a brightness of the pupil in the at least one image with a brightness threshold.

4. The eye-tracking method of claim 1 , further comprising:
enabling a first light source of the array of light sources to emit non-visible light to illuminate the eye;
obtaining a first image of the eye while the first light source is enabled;
enabling a second light source of the array of light sources to emit non-visible light to illuminate the eye;
obtaining a second image of the eye while the second light source is enabled; and
determining the position of the eye based on a position of the first light source within the array of light sources in response to determining that the pupil of the eye in the first image is brighter than the pupil of the eye in the second image.

5. The eye-tracking method of claim 4 , further comprising:
determining the position of the eye based on a position of the second light source within the array of light sources in response to determining that the pupil of the eye in the second image is brighter than the pupil of the eye in the first image.

6. The eye-tracking method of claim 1 , wherein the non-visible light comprises infrared or near-infrared light.

7. The eye-tracking method of claim 1 , further comprising:
enabling a first grouping of light sources of the array of light sources;
obtaining a first image of the eye while the first grouping of light sources are enabled;
enabling a second grouping of light sources of the array of light sources;
obtaining a second image of the eye while the second grouping of light sources are enabled;
comparing a brightness of the pupil in the first image with a brightness of the pupil in the second image; and
determining that the pupil is aligned with the first grouping of light sources in response to determining that the pupil in the first image is brighter than the pupil in the second image.

8. The eye-tracking method of claim 7 , further comprising:
individually enabling each light source of the first grouping in response to determining that the pupil is aligned with the first grouping of light sources;
obtaining respective images of the eye while each light source of the first grouping of light sources are individually enabled; and
determining that one image of the respective images indicates the bright pupil condition, wherein determining the position of the eye is based on a position of one of the light sources included in the first grouping that corresponds to the one image that indicates the bright pupil condition.

9. The eye-tracking method of claim 7 , further comprising:
determining that the pupil is aligned with the second grouping of light sources in response to determining that the pupil in the second image is brighter than the pupil in the first image;
individually enabling each light source of the second grouping in response to determining that the pupil is aligned with the second grouping of light sources;
obtaining respective images of the eye while each light source of the second grouping of light sources is individually enabled; and
determining that one image of the respective images indicates the bright pupil condition, wherein determining the position of the eye is based on a position of one of the light sources included in the second grouping that corresponds to the one image that indicates the bright pupil condition.

10. An eye-tracking system, comprising:
an array of light sources, wherein each light source of the array of light sources is configured to be selectively enabled to emit non-visible light to an eyeward side of the eye-tracking system to illuminate an eye;
a camera disposed on the eyeward side of the eye-tracking system, wherein the camera is configured to capture images of the eye based on the non-visible light;
an optical combiner disposed on an optical axis between each light source of the array of light sources and the eye on the eyeward side of the eye-tracking system, wherein the optical combiner is configured as a holographic optical element or a volume hologram to receive reflected non-visible light that is reflected by the eye and to direct the reflected non-visible light to the camera to generate the images of the eye; and
a computing device communicatively coupled to the array of light sources and the camera, wherein the computing device comprises:
a light source control module configured to enable at least one light source of the array of light sources;
a camera interface module configured to obtain at least one image of the eye, captured by the camera while the at least one light source was enabled;
a bright pupil detection module configured to detect whether the at least one image indicates a bright pupil condition; and
a position determination module configured to determine a position of the eye based on a position of the at least one light source within the array of light sources in response to the bright pupil detection module determining that the at least one image indicates the bright pupil condition.

11. The eye-tracking system of claim 10 , where the bright pupil detection module is configured to:
compare a brightness of the pupil in the at least one image with a brightness of the pupil in another image that corresponds to when another light source of the array of light sources is enabled to emit non-visible light to illuminate the eye.

12. The eye-tracking system of claim 10 , wherein the bright pupil detection module is configured to:
compare a brightness of the pupil in the at least one image with a brightness threshold.

13. The eye-tracking system of claim 10 , wherein the non-visible light comprises infrared or near-infrared light.

14. The eye-tracking system of claim 10 , wherein the optical combiner is configured to diffract the reflected non-visible light to the camera to generate the images of the eye.

15. The eye-tracking system of claim 14 , wherein the array of light sources comprises a transparent substrate and wherein each light source of the array of light sources is disposed on the transparent substrate.

16. The eye-tracking system of

Assignees

• Meta Platforms Tech Llc

Inventors

• Sharma Robin
• El-Haddad Mohamed Tarek

Classifications

• G02B27/0093 Primary

  with means for monitoring data relating to the user, e.g. head-tracking, eye-tracking · CPC title

• G02B27/0172

  characterised by optical features · CPC title

• G06F3/013

  Eye tracking input arrangements (G06F3/015 takes precedence) · CPC title

• G06T7/0016

  involving temporal comparison · CPC title

• G06V40/18

  Eye characteristics, e.g. of the iris · CPC title