Method and system for eye tracking using speckle patterns

1. A method of tracking a gaze of an eye of a user, the method comprising:

obtaining a pre-calibrated speckle map of the eye of the user by:

directing a first light beam at the eye, the eye reflecting a portion of the first light beam;

detecting a plurality of first speckle patterns formed at a detector by the portion of the first light beam reflected by the eye, each of the plurality of first speckle patterns corresponding to a respective first position of the eye;

recording a plurality of images of the eye using a camera, each of the plurality of images of the eye being recorded when a respective first speckle pattern is detected;

determining the respective first position of the eye corresponding to each respective first speckle pattern based on the respective image of the eye; and

storing the plurality of first speckle patterns and the corresponding first positions of the eye;

determining a starting position of the eye using the pre-calibrated speckle map by:

directing a second light beam at the eye, the eye reflecting a portion of the second light beam;

detecting a plurality of second speckle patterns formed at the detector by the portion of the second light beam reflected by the eye; and

determining the starting position of the eye based on comparisons between the plurality of second speckle patterns and the stored plurality of first speckle patterns and the stored corresponding first positions of the eye; and

tracking movement of the eye relative to the starting position by:

directing a third light beam at the eye, the eye reflecting a portion of the third light beam;

detecting a plurality of third speckle patterns formed at the detector by the portion of the third light beam reflected by the eye, the plurality of third speckle patterns being detected at a predetermined frame rate; and

tracking movement of the eye relative to the starting position by tracking the third plurality of speckle patterns from frame to frame.

2. The method of claim 1 wherein each of the portion of the first light beam reflected by the eye, the portion of the second light beam reflected by the eye, and the portion of the third light beam reflected by the eye is diffusely reflected or specular reflected by the eye.

3. The method of claim 1 wherein tracking the third plurality of speckle patterns is performed using an optical flow algorithm.

4. The method of claim 3 wherein the optical flow algorithm comprises a phase correlation algorithm.

5. The method of claim 1 wherein the predetermined frame rate is greater than about 50 frames per second and less than about 15,000 frames per second.

6. The method of claim 1 further comprising:

determining that the eye has blinked;

determining a new starting position of the eye by:

directing a fourth light beam at the eye, the eye reflecting a portion of the fourth light beam;

detecting a plurality of fourth speckle patterns formed at the detector by the portion of the fourth light beam reflected by the eye; and

determining the new starting position of the eye based on comparisons between the plurality of fourth speckle patterns and the stored plurality of first speckle patterns and the stored corresponding first positions of the eye; and

tracking movement of the eye relative to the new starting position by:

directing a fifth light beam at the eye, the eye reflecting a portion of the fifth light beam;

detecting a plurality of fifth speckle patterns formed at the detector by the portion of the fifth light beam reflected by the eye, the plurality of fifth speckle patterns being detected at the predetermined frame rate; and

tracking movement of the eye relative to the new starting position by tracking the fifth plurality of speckle patterns from frame to frame.

7. The method of claim 1 wherein each of the first light beam, the second light beam, and the third light beam comprises infrared radiation.