Eye tracking system and a corresponding method
AssigneeTobii AB
InventorMAGNUS IVARSSON
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Abstract
A method of calibrating an eye-tracking system for use with a camera, wherein in use the eye-tracking system obtains a plurality of images of a user's eye from the camera, uses a normalisation process to convert the images to a normalised image space based on at least one intrinsic property of the camera, and uses a gaze determination process to determine an estimate of the gaze of the user's eye based on the normalised images.
Claims20
A method of calibrating an eye-tracking system for use with a camera, wherein in use the eye-tracking system obtains a plurality of images of a user's eye from the camera, uses a normalisation process to convert the images to a normalised image space based on at least one intrinsic property of the camera, and uses a gaze determination process to determine an estimate of the gaze of the user's eye based on the normalised images, the method of calibrating the eye-tracking system comprising:
- obtaining a calibration image of a user's eye from the camera while the user is instructed to look at a calibration point;
- obtaining potential values for at least one intrinsic property of the camera;
- converting the calibration image using the normalisation process based on the potential values for the at least one intrinsic property of the camera to generate corresponding normalised calibration images;
- processing the normalised calibration images using the gaze detection process;
- and
- determining which of the normalised calibration images best estimates the gaze of a user's eye relative to the expected gaze when the user looks at the calibration point;
- and
- setting the normalisation process for subsequent use of the eye-tracking system to use the value for the at least one intrinsic property of the camera that was used to generate the normalised calibration image that best estimated the expected gaze when the user looks at the calibration point.
An eye-tracking system for use with a camera, wherein the eye-tracking system is configured to obtain a plurality of images of a user's eye from the camera, use a normalisation process to convert the images to a normalised image space based on at least one intrinsic property of the camera, and use a gaze determination process to determine an estimate of the gaze of the user's eye based on the normalised images;
- and
- the eye-tracking system is further configured to:
- obtain a calibration image of a user's eye from the camera while the user is instructed to look at a calibration point;
- obtain potential values for at least one intrinsic property of the camera;
- convert the calibration image using the normalisation process based on the potential values for the at least one intrinsic property of the camera to generate corresponding normalised calibration images;
- process the normalised calibration images using the gaze detection process;
- determine which of the normalised calibration images best estimates the gaze of a user's eye relative to the expected gaze when the user looks at the calibration point;
- and
- set the normalisation process for subsequent use of the eye-tracking system to use the value for the at least one intrinsic property of the camera that was used to generate the normalised calibration image that best estimated the expected gaze when the user looks at the calibration point.
Dependencies are inferred from the claim text.