Non-contact eye gaze tracking

• US 10,162,413 B2
• Filed: 03/28/2017
• Issued: 12/25/2018
• Est. Priority Date: 03/28/2017
• Status: Active Grant

• Current Assignee: Synaptics Incorporated
• Original Assignee: Synaptics Incorporated
• Inventors: Tanemura, Tetsuo
• Primary Examiner(s): Osorio, Ricardo L
• Application Number:
  US15/471,839
• Publication Number:
  US 20180284883A1
• Time in Patent Office: 637 Days
• CPC Class Codes: G06F 2203/04108 Touchless 2D- digitiser, i.e. digitiser detecting the X/Y position of the input means, finger or stylus, also when it does not touch, but is proximate to the digitiser's interaction surface without distance measurement in the Z direction
• CPC Class Codes: G06F 3/013 Eye tracking input arrangements G06F3/015 takes precedence
• CPC Class Codes: G06F 3/044 by capacitive means

Abstract

A method and apparatus for determining an eye gaze direction of a user through one or more non-contact capacitive sensors. For at least some embodiments, a differential capacitance associated with a users'"'"' eye may be determined through at least one of the non-contact capacitive sensors. The differential capacitance may be based on capacitance measurements associated with the users'"'"' eye performed at different times. The eye gaze direction may be based, at least in part, on the determined differential capacitance. For some embodiments, two or more non-contact capacitive sensors may be positioned along an axis. Differential capacitance measurements from the two or more non-contact capacitive sensors may determine the eye gaze direction with respect to the axis.

Claims

1. A method for determining eye gaze information, comprising:

determining, by a first non-contact capacitance sensor, a first capacitance associated with a first eye at a first time;

determining, by a second non-contact capacitance sensor, a second capacitance associated with a second eye at the first time;

determining a first spatial differential capacitance between the first capacitance and the second capacitance;

determining, by the first non-contact capacitance sensor, a third capacitance associated with the first eye at a second time;

determining a first temporal differential capacitance between the first capacitance and the third capacitance;

determining, by the second non-contact capacitance sensor, a fourth capacitance associated with the second eye at the second time; and

determining a second temporal differential capacitance between the second capacitance and the fourth capacitance, and

determining eye gaze information based at least in part on the first spatial differential capacitance, the first temporal differential capacitance, and the second temporal differential capacitance.

2. The method of claim 1, wherein the eye gaze information is determined if the first spatial differential capacitance is greater than a first threshold.

3. The method of claim 1, wherein the eye gaze information indicates an eye gaze direction along an axis determined by a position of the first non-contact capacitance sensor and the second non-contact capacitance sensor.

4. The method of claim 1, further comprising:

comparing the first temporal differential capacitance to a second threshold; and

comparing the second temporal differential capacitance to a third threshold,

wherein the eye gaze information indicates an eye gaze toward the first non-contact capacitance sensor if the first temporal differential capacitance is greater than the second threshold and the second temporal differential capacitance is less than the third threshold.

5. The method of claim 4, wherein the eye gaze information indicates an eye gaze toward the second non-contact capacitance sensor if the first temporal differential capacitance is less than the second threshold and the second temporal differential capacitance is greater than the third threshold.

6. The method of claim 1, further comprising:

determining a second spatial differential capacitance between the third capacitance and the fourth capacitance, and

determining at least one from the group consisting of;

a maximum capacitance between the first spatial differential capacitance and the second spatial differential capacitance,

a minimum capacitance between the first spatial differential capacitance and the second spatial differential capacitance; and

an average capacitance between the first spatial differential capacitance and the second spatial differential capacitance,

wherein the eye gaze information is based at least in part on at least one from the group consisting of the maximum, minimum, and average capacitance.

7. An input device comprising:

a first non-contact capacitance sensor;

a second non-contact capacitance sensor;

a sensor interface circuit coupled to the first non-contact capacitance sensor and the second non-contact capacitance sensor and configured to determine capacitance values based at least in part on signals from the first non-contact capacitance sensor and the second non-contact capacitance sensor; and

a controller coupled to the sensor interface circuit and configured to;

determine a first capacitance associated with a first eye and the first non-contact capacitance sensor at a first time;

determine a second capacitance associated with a second eye and the second non-contact capacitance sensor at the first time;

determine a first spatial differential capacitance between the first capacitance and the second capacitance;

determine a third capacitance associated with the first eye and the first non-contact capacitance sensor at a second time;

determine a first temporal differential capacitance between the first capacitance and the third capacitance;

determine a fourth capacitance associated with the second eye and the second non-contact capacitance sensor at the second time;

determine a second temporal differential capacitance between the second capacitance and the fourth capacitance; and

determine eye gaze information based at least in part on the first spatial differential capacitance, the first temporal differential capacitance, and the second temporal differential capacitance.

8. The input device of claim 7, wherein the eye gaze information is determined if the first spatial differential capacitance is greater than a first threshold.

9. The input device of claim 7, wherein the eye gaze information indicates an eye gaze in a direction along an axis determined by a position of the first non-contact capacitance sensor and the second non-contact capacitance sensor.

10. The input device of claim 7, wherein the controller is further configured to:

compare the first temporal differential capacitance to a second threshold; and

compare the second temporal differential capacitance to a third threshold, wherein the eye gaze information indicates an eye gaze toward the first non-contact capacitance sensor if the first temporal differential capacitance is greater than the second threshold and the second temporal differential capacitance is less than the third threshold.

11. The input device of claim 10, wherein the eye gaze information indicates an eye gaze toward the second non-contact capacitance sensor if the first temporal differential capacitance is less than the second threshold and the second temporal differential capacitance is greater than the third threshold.

12. The input device of claim 7, wherein the controller is further configured to:

determine a second spatial differential capacitance between the third capacitance and the fourth capacitance; and

determine at least one from the group consisting of;

a maximum capacitance between the first spatial differential capacitance and the second spatial differential capacitance,

a minimum capacitance between the first spatial differential capacitance and the second spatial differential capacitance; and

an average capacitance between the first spatial differential capacitance and the second spatial differential capacitance,

wherein the eye gaze information is based at least in part on at least one from the group consisting of the maximum, minimum, and average capacitance.

13. An electronic system, comprising

a display device;

and

an input device comprising;

a first non-contact capacitance sensor;

a second non-contact capacitance sensor;

a sensor interface circuit coupled to the first non-contact capacitance sensor and the second non-contact capacitance sensor and configured to determine capacitance values based on signals from the first non-contact capacitance sensor and the second non-contact capacitance sensor; and

a controller coupled to the sensor interface circuit and configured to;

determine a first capacitance associated with a first eye and the first non-contact capacitance sensor at a first time;

determine a second capacitance associated with a second eye and the first non-contact capacitance sensor at the first time;

determine a first spatial differential capacitance between the first capacitance and the second capacitance;

determine a third capacitance associated with the first eye and the first non-contact capacitance sensor at a second time;

determine a first temporal differential capacitance between the first capacitance and the third capacitance;

determine a fourth capacitance associated with the second eye and the second non-contact capacitance sensor at the second time;

determine a second temporal differential capacitance between the second capacitance and the fourth capacitance; and

determine eye gaze information based at least in part on the first spatial differential capacitance, the first temporal differential capacitance, and the second temporal differential capacitance.

14. The electronic system of claim 13, wherein the eye gaze information indicates an eye gaze in a direction along an axis determined by a position of the first non-contact capacitance sensor and the second non-contact capacitance sensor.

15. The electronic system of claim 13, wherein the controller is further configured to:

compare the first temporal differential capacitance to a first threshold; and

compare the second temporal differential capacitance to a second threshold, wherein the eye gaze information indicates an eye gaze toward the first non-contact capacitance sensor if the first temporal differential capacitance is greater than the first threshold and the second temporal differential capacitance is less than the second threshold.

16. The electronic system of claim 15, wherein the eye gaze information indicates an eye gaze toward the second non-contact capacitance sensor if the first temporal differential capacitance is less than the first threshold and the second temporal differential capacitance is greater than the second threshold.

17. The electronic system of claim 13, wherein the controller is further configured to:

determine a second spatial differential capacitance between the third capacitance and the fourth capacitance; and

determine at least one from the group consisting of;

a maximum capacitance between the first spatial differential capacitance and the second spatial differential capacitance,

a minimum capacitance between the first spatial differential capacitance and the second spatial differential capacitance; and

an average capacitance between the first spatial differential capacitance and the second spatial differential capacitance,

wherein the eye gaze information is based at least in part on at least one from the group consisting of the maximum, minimum, and average capacitance.