Wearable eye tracking system with slippage detection and correction
Apparatus, systems and methods configured for eye tracking with slippage detection and correction are disclosed. In one example, a method comprises: obtaining a first image and a second image of a person's eye, with an imaging sensor; determining a position relationship between an eyeball center of the eye and the imaging sensor based on the first image and the second image.
1. A method comprising:
obtaining a first image and a second image of a person's eye, with an imaging sensor;
determining a position relationship between an eyeball center of the eye and the imaging sensor based on the first image and the second image;
determining an orientation relationship between the imaging sensor and the person's head;
wherein determining the orientation relationship comprises:
obtaining a first set of gaze vectors while the person's head rotates about a first axis and the eye maintains a first gaze point;
obtaining a second set of gaze vectors while the person's head rotates about a second axis and the eye maintains a second gaze point, or obtaining a third gaze vector while the eye maintains a third gaze point;
determining the orientation relationship based on the first set of gaze vectors, and based on the second set of gaze vectors or the third gaze vector.
2. The method of claim 1 , further comprising determining a relative movement of the imaging sensor with respect to the eyeball center based on the position relationship.
3. The method of claim 1 , wherein the first image and the second image are different.
4. The method of claim 1 , wherein determining the position relationship comprises extracting contours of a pupil or a corneal limbus from the first image and the second image, and determining the position relationship based on the contours.
5. The method of claim 1 , wherein the first image and the second image are obtained during an intentional or random movement of the eye.
6. The method of claim 1 , wherein the imaging sensor comprises more than one camera.
7. The method of claim 1 , wherein the imaging sensor is configured to obtain an image of more than one eye of the person.
8. An apparatus comprising:
an imaging sensor configured to obtain a first image and a second image of a person's eye; and
a computing device comprising a processor configured to determine a position relationship between an eyeball center of the eye and the imaging sensor based on the first image and the second image;
wherein the processor is further configured to determine an orientation relationship between the imaging sensor and the person's head by:
obtaining a first set of gaze vectors while the person's head rotates about a first axis and the eye maintains a first gaze point;
obtaining a second set of gaze vectors while the person's head rotates about a second axis and the eye maintains a second gaze point, or obtaining a third gaze vector while the eye maintains a third gaze point;
determining the orientation relationship based on the first set of gaze vectors, and based on the second set of gaze vectors or the third gaze vector.
9. The apparatus of claim 8 , wherein the processor is further configured to determine a relative movement of the imaging sensor with respect to the eyeball center based on the position relationship.
10. The apparatus of claim 8 , wherein the first image and the second image are different.
11. The apparatus of claim 8 , wherein the processor is further configured to determine the position relationship by extracting contours of a pupil or a corneal limbus from the first image and the second image, and by determining the position relationship based on the contours.
12. The apparatus of claim 8 , wherein the imaging sensor is configured to obtain the first image and the second image during an intentional or random movement of the eye.
13. The apparatus of claim 8 , wherein the imaging sensor comprises more than one camera.
14. The apparatus of claim 8 , wherein the imaging sensor is configured to obtain an image of more than one eye of the person.
15. A method comprising:
obtaining a first set of images of a person's eye, using an imaging sensor, while the person's head rotates about a first axis and the eye maintains a first gaze point;
obtaining a second set of images of the eye, using the imaging sensor, while the person's head rotates about a second axis and the eye maintains a second gaze point, or obtaining a third image, using the imaging sensor, while the eye maintains a third gaze point;
determining an orientation relationship between the imaging sensor and the person's head, based on the first set of images, and based on the second set of images or the third image.
16. The method of claim 15 , further comprising:
obtaining a first set of gaze vectors based on the first set of images;
obtaining a second set of gaze vectors based on the second set of images, or obtaining a third gaze vector based on the third image;
wherein determining the orientation relationship is based on the first set of gaze vectors, and based on the second set of gaze vectors or the third gaze vector.
17. The method of claim 15 , wherein the first gaze point and the second gaze point are different; or wherein the first gaze point and the third gaze point are different.
18. The method of claim 15 , wherein the imaging sensor comprises more than one camera.
19. The method of claim 15 , wherein the imaging sensor is configured to obtain an image of more than one eye of the person.
20. An apparatus comprising:
an imaging sensor;
wherein the imaging sensor is configured to obtain a first set of images of a person's eye, while the person's head rotates about a first axis and the eye maintains a first gaze point;
wherein the imaging sensor is configured to obtain a second set of images of the eye, while the person's head rotates about a second axis and the eye maintains a second gaze point, or to obtain a third image, while the eye maintains a third gaze point;
a computing device comprising a processor configured to determine an orientation relationship between the imaging sensor and the person's head based on the first set of images, and based on the second set of images or the third image.
21. The apparatus of claim 20 , wherein the processor is configured to:
obtain a first set of gaze vectors based on the first set of images;
obtain a second set of gaze vectors based on the second set of images, or obtain a third gaze vector based on the third image; and
determine the orientation relationship based on the first set of gaze vectors, and based on the second set of gaze vectors or the third gaze vector.
22. The apparatus of claim 20 , wherein the first gaze point and the second gaze point are different; or wherein the first gaze point and the third gaze point are different.
23. The apparatus of claim 20 , wherein the imaging sensor comprises more than one camera.
24. The apparatus of claim 20 , wherein the imaging sensor is configured to obtain an image of more than one eye of the person.
25. The method of claim 4 , wherein determining the position relationship based on the contours comprises determining a location of the eyeball center in a 2D image plane of the imaging sensor based on the contours.
26. The apparatus of claim 11 , wherein the processor is further configured to determine the position relationship based on the contours by determining a location of the eyeball center in a 2D image plane of the imaging sensor based on the contours.