Apparatus and method for determining eye gaze from stereo-optic views
First Claim
1. A system for tracking an eye, comprising:
- an optical device with a light emitting source and an optical system, wherein the light source is configured for illuminating the eye and the optical system is configured for providing multiple-images of the eye;
an optoelectronic device for acquiring an image of the eye collected by the optical system;
an image processor for isolating reflections of source illumination in the image and for isolating features of the pupil and extra-pupillary eye structure in the image, wherein isolating features comprises determining the position of such in the image and categorizing as to structure type, where the features are at least those of a pupil;
a pupil-reconstructor for constructing a model of the pupil within the eye, wherein the model of the pupil is constructed from model parameters derived from pupil image features;
a feature-matcher for matching extra-pupillary image features to a common template located by the model of the pupil;
a feature-locater for locating matched features from multiple images in a coordinate system common to the optical device; and
a gaze processor for estimating the visual line-of sight for the eye in the said coordinate system;
wherein the multiple images are stereo-views about an optical axis of the system with centering on the eye-orbit.
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Accused Products
Abstract
The invention, exemplified as a single lens stereo optics design with a stepped mirror system for tracking the eye, isolates landmark features in the separate images, locates the pupil in the eye, matches landmarks to a template centered on the pupil, mathematically traces refracted rays back from the matched image points through the cornea to the inner structure, and locates these structures from the intersection of the rays for the separate stereo views. Having located in this way structures of the eye in the coordinate system of the optical unit, the invention computes the optical axes and from that the line of sight and the torsion roll in vision. Along with providing a wider field of view, this invention has an additional advantage since the stereo images tend to be offset from each other and for this reason the reconstructed pupil is more accurately aligned and centered.
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Citations
20 Claims
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1. A system for tracking an eye, comprising:
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an optical device with a light emitting source and an optical system, wherein the light source is configured for illuminating the eye and the optical system is configured for providing multiple-images of the eye; an optoelectronic device for acquiring an image of the eye collected by the optical system; an image processor for isolating reflections of source illumination in the image and for isolating features of the pupil and extra-pupillary eye structure in the image, wherein isolating features comprises determining the position of such in the image and categorizing as to structure type, where the features are at least those of a pupil; a pupil-reconstructor for constructing a model of the pupil within the eye, wherein the model of the pupil is constructed from model parameters derived from pupil image features; a feature-matcher for matching extra-pupillary image features to a common template located by the model of the pupil; a feature-locater for locating matched features from multiple images in a coordinate system common to the optical device; and a gaze processor for estimating the visual line-of sight for the eye in the said coordinate system; wherein the multiple images are stereo-views about an optical axis of the system with centering on the eye-orbit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method for tracking the eye, comprising:
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illuminating the eye; acquiring images, at the least a single image, of the eye; isolating reflections of the means of illumination in an image; isolating features of the pupil and extra-pupillary eye structure in the image, wherein isolating features comprises determining the position of such in the image and categorizing as to the nature, where the features are at least those of a pupil; constructing a model of the pupil within the eye, wherein the model of the pupil is constructed from model parameters derived from pupil image features; matching extra-pupillary image features to a common template located by the model of the pupil; locating the matched features in a coordinate system common to the means of acquiring an image; and determining the visual line-of sight for the eye in the said coordinate system. - View Dependent Claims (14, 15, 16, 17, 18, 19)
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20. A method for tracking the eye with a hand-holdable device, comprising:
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illuminating the face of a user; acquiring multiple images of the face; isolating an image of the face in an acquired image; isolating at least one eye in the face image; isolating the eye-orbit of the eye in the image; isolating an eye image centered on the eye-orbit; isolating reflections of the means of illumination in the eye image; isolating features of the pupil and extra-pupillary eye structure in the image, wherein isolating features comprises determining the position of such in the image and categorizing as to the nature, where the features are at least those of a pupil; constructing a model of the pupil within the eye, wherein the model of the pupil is constructed from model parameters derived from pupil image features; matching extra-pupillary image features to a common template located by the model of the pupil; locating the matched features in a coordinate system common to the means of acquiring images; and determining the visual line-of sight for the eye in the said coordinate system; wherein the multiple images are stereo-views about an optical axis of light collecting optics incorporated with the hand-holdable device.
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Specification