Adaptive camera and illuminator eyetracker

Patent metadata

Field	Value
Publication number	US-9649029-B2
Application number	US-201414563063-A
Country	US
Kind code	B2
Filing date	Dec 8, 2014
Priority date	Apr 1, 2009
Publication date	May 16, 2017
Grant date	May 16, 2017

Abstract

A method includes obtaining an image of an eye in a bright-pupil imaging mode in which a retinal retro-reflection complements the image of the eye in the bright-pupil mode, and obtaining an image of the eye in a dark-pupil imaging mode in which a cornea-scleral retro-reflection complements the image of the eye in the dark-pupil mode. One of the bright-pupil imaging mode and the dark-pupil imaging mode is selected based on quality of obtained images.

First claim

The invention claimed is:

1. A method comprising:
obtaining a first image of an eye in a bright-pupil imaging mode in which said image comprises a retinal retro-reflection;
obtaining a second and differing image of the eye in a dark-pupil imaging mode in which said image comprises a corneo-scleral retro-reflection;
calculating at least one image quality metric for the image of the eye in the bright-pupil imaging mode;
calculating at least one image quality metric for the image of the eye in the dark-pupil imaging mode;
comparing the calculated image quality metric of the first image in the bright-pupil imaging mode with the calculated image quality metric of the second image in the dark-pupil imaging mode;
selecting, based on comparison of the calculated image quality metrics, one of the bright-pupil imaging mode and the dark-pupil imaging mode; and
based on the selected bright-pupil imaging mode or dark-pupil imaging mode, perform tracking of the eye.

2. The method according to claim 1 , wherein the selected imaging mode corresponds to the one of the obtained images of highest quality.

3. The method according to claim 1 , further comprising evaluating the quality of at least one image obtained during the tracking of the eye and revising the selection of the imaging mode based on the evaluation.

4. The method according to claim 1 , further comprising selecting a camera to be active for performing the tracking of the eye in the selected imaging mode.

5. The method according to claim 4 , further comprising selecting a reference illuminator to be active for performing the tracking of the eye and which in combination with the selected camera, provides the selected imaging mode.

6. An eye tracker controller comprising:
a processor configured to control at least a camera to
obtain a first image of an eye in a bright-pupil condition in which said image comprises a retinal retro-reflection,
obtain a second and differing image of the eye in a dark-pupil condition in which said image comprises a corneo-scleral retro-reflection,
calculate at least one image quality metric for the image of the eye in the bright-pupil imaging mode,
calculate at least one image quality metric of the first image for the image of the eye in the dark-pupil imaging mode,
compare the calculated image quality metric of the second image in the bright-pupil imaging mode with the calculated image quality metric in the dark-pupil imaging mode,
select, based on comparison of the calculated image quality metrics, one of the bright-pupil imaging mode and the dark-pupil imaging mode, and
based on the selected bright-pupil imaging mode or dark-pupil imaging mode, perform tracking of the eye.

7. The eye tracker controller according to claim 6 , wherein said processor is configured to select the imaging mode corresponding to the one of the obtained images of highest quality.

8. The eye tracker controller according to claim 6 , wherein said processor is further configured to evaluate the quality of at least one image obtained during the tracking of the eye, and revise the selection of the imaging mode based on the evaluation.

9. The eye tracker controller according to claim 6 , wherein said processor is further configured to select a camera to be active for providing the selected imaging mode.

10. The eye tracker controller according to claim 9 , wherein said processor is further configured to select a reference illuminator to be active for performing the tracking of the eye and which in combination with the selected camera, provides the selected imaging mode.

11. An eye tracker comprising:
a plurality of cameras for imaging an eye, with at least one camera being arranged to image the eye in a bright-pupil mode in which said image comprises a retinal retro-reflection, and with at least one other camera being arranged to image the eye in a dark-pupil mode in which said image comprises a corneo-scleral retro-reflection; and
a controller configured to
obtain a first image of an eye in a bright-pupil condition,
obtain a second and differing image of the eye in a dark-pupil condition,
calculate at least one image quality metric for the image of the eye in the bright-pupil imaging mode,
calculate at least one image quality metric for the image of the eye in the dark-pupil imaging mode,
compare the calculated image quality metric of the first image in the bright-pupil imaging mode with the calculated image quality metric of the second image in the dark-pupil imaging mode,
select, based on comparison of the calculated image quality metrics, one of the bright-pupil imaging mode and the dark-pupil imaging mode, and
based on the selected bright-pupil imaging mode or dark-pupil imaging mode, perform tracking of the eye.

12. The eye tracker according to claim 11 , wherein said controller is configured to select the imaging mode corresponding to the one of the obtained images of highest quality.

13. The eye tracker according to claim 11 , wherein said controller is further configured to evaluate the quality of at least one image obtained during the tracking of the eye, and revise the selection of the imaging mode based on the evaluation.

14. The eye tracker according to claim 11 , wherein said controller is configured to select at least one of said plurality of cameras that is arranged to image the eye in the selected imaging mode.

15. The eye tracker according to claim 14 , further comprising at least one reference illuminator for illuminating the eye; and wherein said controller is further configured to select said at least one reference illuminator, which in combination with said at least one selected camera, provides the selected imaging mode.

16. A computer-program product comprising computer-readable instructions, which when executed on a general-purpose computer, causes an eye tracker to perform the following:
obtaining a first image of an eye in a bright-pupil mode in which said image comprises a retinal retro-reflection;
obtaining a second and differing image of the eye in a dark-pupil mode in which said image comprises a corneo-scleral retro-reflection;
calculating at least one image quality metric for the image of the eye in the bright-pupil imaging mode;
calculating at least one image quality metric for the image of the eye in the dark-pupil imaging mode;
comparing the calculated image quality metric of the first image in the bright-pupil imaging mode with the calculated image quality metric of the second image in the dark-pupil imaging mode;
selecting, based on comparison of the calculated image quality metrics, one of the bright-pupil imaging mode and the dark-pupil imaging mode; and
based on the selected bright-pupil imaging mode or dark-pupil imaging mode, perform tracking of the eye.

Assignees

• Tobii Ab

Inventors

• Blixt Peter
• Troili Gunnar
• Kingbäck Anders
• Elvesjö John Mikael
• Skogö Mårten

Classifications

• A61B3/113 Primary

  for determining or recording eye movement · CPC title

• A61B3/0008

  provided with illuminating means (A61B3/117, A61B3/14 take precedence) · CPC title

• A61B3/14

  Arrangements specially adapted for eye photography · CPC title

• A61B3/145

  by video means · CPC title

• A61B3/0025

  characterised by electronic signal processing, e.g. eye models · CPC title