Methods and systems for a head-mounted device for updating an eye tracking model

1. A method for a head-mounted device for updating an eye tracking model in relation to an eye, wherein the head-mounted device comprises an eye tracking sensor and wherein the eye tracking model relates to a position of the eye tracking sensor and other components of the head-mounted device and a model of each eye, the method comprising:

obtaining, by means of the eye tracking sensor, first sensor data in relation to the eye;

moving the eye tracking sensor along an axis parallel to a line bisecting the eyes, wherein the eye tracking sensor is moved after obtaining the first sensor data;

obtaining, by means of the eye tracking sensor, second sensor data in relation to the eye, wherein the second sensor data are obtained after moving the eye tracking sensor; and

updating the eye tracking model in relation to the eye, based on the first sensor data and the second sensor data.

2. The method of claim 1 , wherein the eye tracking sensor is movably arranged in the head-mounted device.

3. The method of claim 1 , wherein the eye tracking sensor is immovably arranged in the head-mounted device.

4. The method of claim 1 , wherein the eye tracking sensor is arranged in relation to an optical system of the head-mounted device, such that the eye tracking sensor is moved in relation to the eye by moving the optical system in relation to the eye.

5. The method of claim 1 , wherein the eye tracking sensor is arranged in relation to a display movably arranged in the head-mounted device, such that the eye tracking sensor is moved in relation to the eye by moving the display in the head-mounted device in relation to the eye.

6. The method of claim 1 , wherein the first sensor data represent a first image of the eye and the second sensor data represent a second image of the eye, wherein the movement is such that an angle between the eye tracking sensor and the eye is changed, and wherein updating the eye tracking model further comprises:

identifying a position of a feature of the eye in the first image; identifying a position of the feature of the eye in the second image;

determining a distance from the eye tracking sensor to the feature of the eye based on the position of the feature of the eye in the first image, the position of the feature of the eye in the second image, and the movement of the eye tracking sensor; and

updating the eye tracking model in relation to the eye based on the determined distance.

7. The method of claim 1 , further comprising:

further moving the eye tracking sensor in relation to the eye, wherein the eye tracking sensor is further moved after obtaining the second sensor data; and

obtaining, by means of the eye tracking sensor, third sensor data in relation to the eye, wherein the third sensor data are obtained after further moving the eye tracking sensor,

wherein the updating of the eye tracking model in relation to the eye is further based on the third sensor data.

8. The method of claim 1 , wherein the movement of the eye tracking sensor is a known movement.

9. The method of claim 1 , wherein the movement of the eye tracking sensor is a translational movement in relation to the eye.

10. The method of claim 1 , wherein the eye tracking model is updated using a simultaneous localization and mapping, SLAM, algorithm.

11. The method of claim 1 , wherein the eye tracking model is parameterized by a cornea parameter indicative of a radius of curvature of a cornea of the eye of the user, and wherein the updating of the eye tracking model comprises updating a value of the cornea parameter.

12. The method of claim 1 , wherein the eye tracking model is parameterized by a pupil position parameter indicative of a pupil position of the eye of the user, and wherein the updating of the eye tracking model comprises updating a value of the pupil position parameter.

13. A system for a head-mounted device for updating an eye tracking model in relation to an eye, wherein the head-mounted device comprises an eye tracking sensor and wherein the eye tracking model relates to a position of the eye tracking sensor and other components of the head-mounted device and a model of each eye, the system comprising a processor, and a memory, said memory containing instructions executable by said processor, whereby said system is operative to:

obtain, by the eye tracking sensor, first sensor data in relation to the eye;

move the eye tracking sensor along an axis parallel to a line bisecting the eyes, wherein the eye tracking sensor is moved after obtaining the first sensor data;

obtain, by the eye tracking sensor, second sensor data in relation to the eye, wherein the second sensor data are obtained after moving the eye tracking sensor; and

update the eye tracking model in relation to the eye, based on the first sensor data and the second sensor data.

14. A head-mounted device comprising the system of claim 13 .

15. A non-transitory computer-readable storage medium storing instructions which, when executed by a head-mounted device cause the head-mounted device to carry out the steps of:

obtaining, by the eye tracking sensor, first sensor data in relation to the eye;

moving the eye tracking sensor along an axis parallel to a line bisecting the eyes, wherein the eye tracking sensor is moved after obtaining the first sensor data;

obtaining, by the eye tracking sensor, second sensor data in relation to the eye, wherein the second sensor data are obtained after moving the eye tracking sensor; and

updating the eye tracking model in relation to the eye, based on the first sensor data and the second sensor data.