Method and system for controlling an eye tracking system

Patent metadata

Field	Value
Publication number	US-11570370-B2
Application number	US-202017039970-A
Country	US
Kind code	B2
Filing date	Sep 30, 2020
Priority date	Sep 30, 2019
Publication date	Jan 31, 2023
Grant date	Jan 31, 2023

Abstract

There is provided a method, system, and non-transitory computer-readable storage medium for controlling an eye tracking system (200) to obtain a first image (500) captured under active illumination by at least one infrared, IR, illuminator (112, 113) associated with the eye tracking system (200) and at a current exposure setting, using the image sensor device (110); and, if at least one eye (100, 120) is depicted in the first image (500): define at least one region of interest, ROI, (501, 502, 503, 504) from the first image (500) comprising a group of pixels in the first image (500) representing at least a part of the depicted at least one eye (100, 120); determine a respective intensity value for each of the at least one ROI (501, 502, 503, 504); determine a second exposure setting by adjusting at least one exposure parameter of the image sensor device (110) based on the determined intensity value, or values, for the at least one ROI (501, 502, 503, 504); and set the current exposure setting to the second exposure setting.

First claim

The invention claimed is:

1. A computer implemented method for controlling the exposure setting of an image sensor device associated with an eye tracking system to enable eye tracking, the image sensor device being sensitive to IR light, wherein the method comprises:
obtaining, in the eye tracking system, a first image, wherein the first image is captured under active illumination by at least one infrared, IR, illuminator associated with the eye tracking system and at a current exposure setting, using the image sensor device;
determining, using processing circuitry comprised in the eye tracking system, if at least one eye is depicted in the first image, wherein determining if at least one eye is depicted in the first image comprises detecting in the first image at least part of an eye illuminated by IR light from the at least one IR illuminator, wherein said at least one part of an eye comprises at least one glint, at least one pupil, a part of at least one iris, a part of at least one sclera, or a part of at least one eye lid;
if at least one eye is depicted in the first image;
defining, using the processing circuitry, at least one region of interest, ROI, from the first image comprising a group of pixels in the first image representing at least a part of the depicted at least one eye;
determining, using the processing circuitry, a respective intensity value for each of the at least one ROI based on intensity values of the group of pixels in the ROI;
determining a second exposure setting by adjusting, using the processing circuitry, at least one exposure parameter of the image sensor device based on the determined intensity value, or values, of the at least one ROI; and
setting, using the processing circuitry, the current, exposure setting to the second exposure setting;

and further comprising:
after setting the current exposure setting to the second exposure setting, obtaining, using the image sensor device, a second image captured using the image sensor device, the second image being captured under active illumination by at least one infrared, IR, illuminator associated with the eye tracking system;
wherein the at least one IR illuminator is illuminated during an entire exposure time of the image sensor.

2. The method of claim 1 , wherein detecting in the first image, using the processing circuitry, at least part of an eye comprises detecting at least one glint caused by IR light from the at least one IR illuminator or at least one pupil illuminated by IR light from the at least one IR illuminator.

3. The method of claim 1 , wherein defining, using the processing circuitry, at least one region of interest from the first image comprises defining a first region of interest, ROI, for a first eye depicted in the first image and a second region of interest, ROI, for a second eye depicted in the first image.

4. The method of claim 1 , wherein determining the respective intensity value of each of the at least one ROI comprises applying a histogram to the intensity values of all or a selection of the pixels in the ROI.

5. The method of claim 1 , wherein deter lining if at least one eye is depicted in a first image comprises detecting, using the processing circuitry, pixel representing a glint or at least a part of one or more of the iris, the pupil, the sclera, or the eye lid of the least one eye.

6. The method of claim 1 , wherein the at least one exposure parameter of the image sensor device comprises gain and wherein adjusting the at least, one exposure parameter comprises applying a gain to be multiplied to the pixel intensity values of images captured using the image sensor device.

7. The method of claim 1 , wherein the at least one exposure parameter of the image sensor device comprises exposure time and wherein adjusting the at least one exposure parameter comprises adjusting the exposure time to be applied when capturing images using the image sensor device.

8. The method of claim 1 , wherein the at least one exposure parameter of the image sensor device comprises skipping or binning and wherein adjusting the at least one exposure parameter comprises adjusting a skipping or binning read-out scheme for the image sensor device.

9. An eye tracking system, the system comprising an image sensor device being sensitive to IR light and processing circuitry, wherein the processing circuitry is configured to control the exposure setting of the image sensor device, by:
obtaining a first image, wherein the first image is captured under active illumination by at least one infrared, IR, illuminator associated with the eye tracking system and at a current exposure setting, using the image sensor device;
determining if at least one eye is depicted in the first image, wherein determining if at least one eye is depicted in the first image comprises detecting in the first image at least a part of an eye illuminated by 1 R light from the at least one IR illuminator, wherein said at least one part of an eye comprises at least one dint, at least one pupil, a part of at least one iris, a part of at least one sclera, and/or a part of at least one eye lid;
if at least one eye is depicted in the first image:
defining at least one region of interest, ROI, from the first image comprising a group of pixels in the first image representing at least a part of the depicted at least one eye;
determining a respective intensity value for each of the at least one ROI based on intensity values of the group of pixels in the ROI; and
determining a second exposure setting by adjusting at least one exposure parameter of the image sensor device based on the determined intensity value, or values, for the at least one ROI; and
setting the current exposure setting to the second exposure setting;

and further comprising:
after setting the current exposure setting to the second exposure setting, obtaining, using the image sensor device, a second image captured using the image sensor device, the second image being captured under active illumination by at least one infrared, IR, illuminator associated with the eye tracking system;
wherein the at least one IR illuminator is illuminated during an entire exposure time of the image sensor.

10. The system of claim 9 , wherein the processing circuitry is configured to detect in the first image at least a part of an eye by detecting at least one glint caused by IR light from the at least one IR illuminator or at least one pupil illuminated by IR light from the at least one IR illuminator.

11. The system of claim 9 , wherein the processing circuitry is configured to define a first region of interest, ROI, for a first eye depicted in the first image and a second region of interest, ROI, for a second eye depicted in the first image.

12. The system of claim 9 , wherein the processing circuitry is configured to determine the respective intensity value for each of the at least one ROI by applying a histogram to the intensity values of all or a selection of the pixels in the ROI.

13. The system of claim 9 , wherein the processing circuitry is configured to determine if at least one eye is depicted in a first image by detecting pixels representing a glint or at least a part of one or more of the iris, the pupil, the sclera, or the eye lid of the at least one eye.

14. The system of claim 9 , wherein the at least one exposure parameter of the image sensor device comprises gain and wherein the processing circuitry is configured to adjust the at least one exposure parameter by applying a gain to be multiplied to the pixel intensity values of images captured using the image sensor device.

15. The system of claim 9 , w

Assignees

• Tobii Ab

Inventors

• Ivarsson Magnus
• Ollesson Niklas
• Åberg Viktor
• Redz Anna

Classifications

• G06V10/22

  by selection of a specific region containing or referencing a pattern; Locating or processing of specific regions to guide the detection or recognition · CPC title

• G06V10/143

  Sensing or illuminating at different wavelengths · CPC title

• G06V40/19

  Sensors therefor · CPC title

• H04N5/2352 Primary

  Electricity · mapped topic

• G06V40/18 Primary

  Eye characteristics, e.g. of the iris · CPC title