Wearable eye tracking system with slippage detection and correction

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;

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;

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.

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 the first image and the second image are obtained during an intentional or random movement of the eye.

5. The method of claim 1 , further comprising determining an orientation relationship between the imaging sensor and the person's head.

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 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;

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.

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 imaging sensor is configured to obtain the first image and the second image during an intentional or random movement of the eye.

12. The apparatus of claim 8 , wherein the processor is further configured to determine an orientation relationship between the imaging sensor and the person's head.

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 image and a second image of a person's eye, with an imaging sensor;

extracting a first contour of a pupil or a corneal limbus from the first image and extracting a second contour of the pupil or the corneal limbus from the second image;

determining a location of an eyeball center of the eye in a 2D image plane of the imaging sensor based on the first contour and the second contour;

determining a position relationship between the eyeball center and the imaging sensor based on the first contour, the second contour and the location.

16. An apparatus comprising:

an imaging sensor configured to obtain a first image and a second image of a person's eye;

a computing device comprising a processor configured to extract a first contour of a pupil or a corneal limbus from the first image and a second contour of the pupil or the corneal limbus from the second image, to determine a location of an eyeball center of the eye in a 2D image plane of the imaging sensor based on the first contour and the second contour, and to determine a position relationship between the eyeball center and the imaging sensor based on the first contour, the second contour and the location.