Method and system for guiding a user in calibrating an eye tracking device

Patent metadata

Field	Value
Publication number	US-12293017-B2
Application number	US-202418670758-A
Country	US
Kind code	B2
Filing date	May 22, 2024
Priority date	May 25, 2023
Publication date	May 6, 2025
Grant date	May 6, 2025

Abstract

A computer-implemented method for guiding a user in calibrating a wearable eye tracking device is disclosed. The method comprises determining a calibration point and an initial gaze point of a user wearing the eye tracking device. The method further comprises displaying a calibration marker on a remote display device at the initial gaze point, wherein the calibration marker is configured to indicate a direction. The method further comprises, in response to a movement of the gaze point in relation to the calibration point caused by movement of the user's head and/or movement of the remote display device, determining a current gaze point, and updating the calibration marker in accordance with a calculated direction and/or the distance from the current gaze point to the calibration point.

First claim

The invention claimed is:

1. A computer-implemented method for guiding a user in calibrating a wearable eye tracking device, the method comprising:
determining a calibration point in a first fixed coordinate system associated with a scene camera of the eye tracking device;
determining an initial gaze point of a user wearing the eye tracking device, the initial gaze point being determined in the first fixed coordinate system, and being determined in a second fixed coordinate system associated with a remote display device when the second fixed coordinate system overlaps with the first fixed coordinate system;
calculating a first direction and a first distance from the initial gaze point to the calibration point in the first fixed coordinate system;
displaying a calibration marker on the remote display device at the initial gaze point, wherein the calibration marker is configured to indicate the first direction;
in response to a movement of the gaze point in relation to the calibration point caused by movement of the user's head while wearing the eye tracking device and/or movement of the remote display device:
determining a current gaze point in the first fixed coordinate system;
calculating a second direction and a second distance from the current gaze point to the calibration point in the first fixed coordinate system; and
updating the calibration marker in accordance with the second direction and/or the second distance.

2. The method of claim 1 , wherein updating the calibration marker comprises changing an appearance of the calibration marker depending on a change in the second direction and/or the second distance.

3. The method of claim 2 , wherein changing the appearance of the calibration marker comprises:
reducing a size of the calibration marker upon the second distance being smaller than the first distance, and enlarging the calibration marker upon the second distance being larger than the first distance; and/or
recoloring the calibration marker upon the second distance being different from the first distance.

4. The method of claim 2 , wherein changing the appearance of the calibration marker comprises changing a graphical icon of the calibration marker upon the second distance being within a calibration distance of the calibration point.

5. The method of claim 3 , wherein changing the appearance of the calibration marker comprises changing a graphical icon of the calibration marker upon the second distance being within a calibration distance of the calibration point.

6. The method of claim 1 , further comprising, in response to the movement of the gaze point in relation to the calibration point, providing additional feedback to the user, said additional feedback being one or more of: a haptic feedback, a visual feedback, or an audio feedback in accordance with the second direction and/or the second distance.

7. The method of claim 1 , further comprising performing a calibration of the eye tracking device with respect to the calibration point upon the second distance being within a calibration distance of the calibration point.

8. The method of claim 7 , wherein performing the calibration depends on the user's gaze being maintained within a calibration margin of the calibration distance until a predetermined condition is met.

9. The method of claim 8 , wherein the calibration distance and the calibration margin are different radiuses of substantially circular shapes having their respective centers at the calibration point.

10. The method of claim 8 , wherein the predetermined condition is a number of frames captured by a scene camera of the eye tracking device and/or a fixation time.

11. The method of claim 9 , wherein the predetermined condition is a number of frames captured by a scene camera of the eye tracking device and/or a fixation time.

12. The method of claim 7 , further comprising, as a response to performing the calibration of the eye tracking device with respect to the calibration point, for one or more consecutive calibration points:
calculating a next direction and a next distance from the current gaze point to one of the consecutive calibration points; and
updating the calibration marker in accordance with the next direction and/or the next distance.

13. The method of claim 12 , further comprising determining a user calibration profile of the user of the eye tracking device as a result of performing the calibration of the calibration point and the one or more consecutive calibration points.

14. The method of claim 1 , wherein the user's head remains substantially fixed while wearing the eye tracking device.

15. The method of claim 1 , wherein the eye tracking device is a display-less eye tracking device.

16. A non-transitory computer-readable storage medium having stored thereon computer-executable instructions that, when executed by processing circuitry cause the processing circuitry to carry out the method according to claim 1 .

17. An eye tracking system comprising a wearable eye tracking device, a remote display device, processing circuitry and a memory containing instructions executable by said processing circuitry, wherein the eye tracking device comprises a scene camera and an eye tracking camera, wherein the processing circuitry is configured to:
determine a calibration point in a first fixed coordinate system associated with the scene camera;
determine an initial gaze point of a user wearing the eye tracking device using the eye tracking camera and the scene camera, the initial gaze point being determined in the first fixed coordinate system, and being determined in a second fixed coordinate system associated with the remote display device when the second fixed coordinate system overlaps with the first fixed coordinate system;
calculate a first direction and a first distance from the initial gaze point to the calibration point in the first fixed coordinate system;
cause the remote display device to display a calibration marker at the initial gaze point, wherein the calibration marker is configured to indicate the first direction;
in response to a movement of the gaze point in relation to the calibration point caused by movement of the user's head while wearing the eye tracking device and/or movement of the remote display device:
determine a current gaze point in the fixed coordinate system;
calculate a second direction and a second distance from the current gaze point to the calibration point in the first fixed coordinate system; and
cause the remote display device to update the calibration marker in accordance with the second direction and/or second distance.

18. The eye tracking system of claim 17 , wherein the wearable eye tracking device is a display-less eye tracking device.

19. The eye tracking system of claim 18 , wherein the wearable eye tracking device comprises a frame, at least one lens attached to the frame, an outward-facing image sensor and an eye tracking arrangement.

20. The eye tracking system of claim 19 , wherein the remote display device is a smartphone, a tablet, a smartwatch, a laptop or a device capable of displaying information.

Assignees

• Tobii Ab

Inventors

• Clausen Anders
• Mobrin Mathias

Classifications

• G06T2207/30204

  Marker · CPC title

• G06T2207/30201

  Face · CPC title

• G06T7/20

  Analysis of motion (motion estimation for coding, decoding, compressing or decompressing digital video signals H04N19/43, H04N19/51) · CPC title

• G06F3/04845

  for image manipulation, e.g. dragging, rotation, expansion or change of colour · CPC title

• G06F3/04817

  using icons (graphical or visual programming using iconic symbols G06F8/34) · CPC title