Eye tracking based on imaging eye features and assistance of structured illumination probe light

Patent metadata

Field	Value
Publication number	US-11675427-B2
Application number	US-201916549863-A
Country	US
Kind code	B2
Filing date	Aug 23, 2019
Priority date	Aug 27, 2018
Publication date	Jun 13, 2023
Grant date	Jun 13, 2023

Abstract

Disclosed are techniques and devices for optical eye tracking based on imaging the eye and tracking certain images of eye features in the eye. The disclosed techniques and devices can be implemented to use structured light to illuminate an eye for obtaining images of the eye to generate accurate eye movement information.

First claim

What is claimed is:

1. An eye-tracking device, comprising:
a support structure attachable to a user;
one or more probe light sources placed on the support structure to produce illumination probe light;
an optical device placed on the support structure to receive the illumination probe light and to direct the illumination probe light to illuminate an eye of the user, wherein the optical device includes an optical projector that modulates the illumination probe light to carry a pattern as a spatial position reference and to project the illumination probe light with the pattern over the eye without scanning the illumination probe light;
an optical detector array placed on the support structure to include optical detectors to capture images of the eye under illumination to produce detector signals from the optical detectors;
an optical imaging module placed on the support structure to image the eye onto the optical detector array and to collect and image optical reflection of the illumination probe light with the pattern of the spatial position reference from the eye onto the optical detector array; and
a processor coupled to receive and process the detector signals including the captured images from the optical detector array and operable to extract from the captured images an optical signature produced by a unique physical feature of the eye comprising a complex interwoven texture of an iris that is unique to each person wherein the complex interwoven texture includes signature points that are unique to each person in each captured image of the eye based on the pattern in the illumination probe light as the spatial position reference to determine positions of the signature points of the eye in each captured image of the eye and to monitor a change in the positions of the signature points of the eye in each captured image of the eye to track the eye, wherein the processor is operable to determine the positions of the signature points of the eye in each captured image of the eye based on row and column positions of optical detectors in the optical detector array that capture the captured images, wherein as the eye moves the positions of the signature points of the eye change causing change in the row and the column positions of optical detectors in the optical detector array that capture the signature points of the eye, wherein the processing the detector signals from the optical detector array further tracks the eye by determining a position of the eye in a three-dimensional coordinate system based on the illumination probe light with the pattern of the spatial position reference.

2. The device as in claim 1 , wherein the optical device includes an optical projector that modulates the illumination probe light to carry a pattern as a spatial position reference for the processor to determine the position of the optical image of a feature of the eye in each captured image of the eye.

3. The device as in claim 2 , wherein the optical device includes an optical projector that modulates the illumination probe light to carry a periodic spatial pattern to determine the position of the optical image of a feature of the eye in each captured image of the eye.

4. The device as in claim 2 , wherein the optical device includes an optical projector that modulates the illumination probe light to carry a coded non-periodic pattern to determine the position of the optical image of a feature of the eye in each captured image of the eye.

5. The device as in claim 2 , wherein the optical projector includes a diffractive optical element.

6. The device as in claim 1 , wherein the support structure attachable to the user is a pair of goggles.

7. The device as in claim 1 , wherein the processor is structured to detect one or more images of an iris of the eye as part of the optical signature to determine a bio-identifier map for the user.

8. The device as in claim 1 , wherein the processing the detector signals from the optical detector array further determines an aperture of a pupil of the eye, eye flashing movements, and eyelid blink movements.

9. A method for using optical imaging to track an eye, comprising:
attaching a device to a user;
projecting illumination probe light to illuminate an eye of the user;
modulating the illumination probe light to carry a pattern as a spatial position reference so that the illumination probe light is projected onto the eye with the pattern over the eye without scanning the illumination probe light;
operating an optical detector array with optical detectors located in the device to receive an optical reflection of the illumination probe light with the spatial pattern from the eye under illumination to produce detector signals from the optical detectors representing a detected image of the eye;
operating an optical imaging module in an optical path of the optical reflection from the eye to the optical detector array to image the eye onto the optical detector array and to collect and image the optical reflection of the illumination probe light with the pattern of the spatial position reference from the eye onto the optical detector array; and
processing the detector signals from the optical detector array to generate an optical image of the eye and to identify an optical signature produced by a unique physical feature comprising a complex interwoven texture of an iris that is unique to each person wherein the complex interwoven texture includes signature points that are unique to each person within the detected image of the eye based on the pattern as the spatial position reference in an optical refection of the illumination probe light to determine the positions of the signature points of the eye and to monitor a change in the positions of the signature points of the eye in the detected image of the eye to track the eye, wherein the processing determines the positions of the signature points of the eye in each captured image of the eye based on row and column positions of optical detectors in the optical detector array that capture the captured images, wherein as the eye moves the positions of the signature points of the eye change causing change in the row and the column positions of optical detectors in the optical detector array that capture the signature points of the eye, wherein the processing the detector signals from the optical detector array further tracks the eye by determining a position of the eye in a three-dimensional coordinate system based on the illumination probe light with the pattern of the spatial position reference.

10. The method as in claim 9 , comprising:
modulating the illumination probe light to carry a spatial pattern to illuminate the eye of the user;
operating the optical detector array to image the eye;
processing the detector signals from the optical detector array in imaging the eye to generate (1) an optical image of the spatial pattern in the modulated illumination probe light reflected from the eye and (2) the optical image of the eye that overlaps with the optical image of the spatial pattern; and
processing the optical images to determine a position or motion of the eye based on information of the optical image of the signature points of the eye within the generated image of the eye with reference to known locations in the optical image of the spatial pattern reflected from the eye.

11. The method as in claim 10 , comprising:
using a periodic pattern as the spatial pattern on the illumination probe light, wherein the periodic pattern includes a pattern of spots or isolated patterns.

12. The method as in claim 10 , comprising:
using a coded pattern as the spatial pattern on the illumination probe light.

Assignees

• Shenzhen Goodix Tech Co Ltd

Inventors

• He Yi
• Pi Bo

Classifications

• G01P13/00

  Indicating or recording presence, absence, or direction, of movement (electric switches H01H; counting moving objects G06M7/00) · CPC title

• G06T2207/30201

  Face · CPC title

• G06F3/013 Primary

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

• G06T7/73

  using feature-based methods · CPC title

• G06V40/193

  Preprocessing; Feature extraction · CPC title