SYSTEMS, DEVICES, AND METHODS FOR LASER EYE TRACKING
First Claim
1. A method of determining a gaze direction of a user, the method comprising:
- scanning a laser light over at least a portion of an eye of the user by a scanning laser device, wherein the portion of the eye of the user includes at least a portion of a cornea of the eye of the user;
detecting reflections of the laser light from the eye by at least one photodetector;
determining a relative intensity of each reflection by a processor;
identifying, by the processor, at least one region of the eye that corresponds to a relatively low-intensity reflection;
determining, by the processor, a position of the cornea based on the at least one region of the eye that corresponds to the relatively low-intensity reflection; and
determining, by the processor, the gaze direction of the user based on the position of the cornea.
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Accused Products
Abstract
Systems, devices, and methods for laser eye tracking are described. Laser eye tracking involves scanning laser light over the eye and detecting diffuse reflections of the laser light with one or more photodetector(s). While conventional camera-based eye tracking techniques rely on detecting and identifying specific reflections (i.e., Purkinje images such as the “glint”), the laser eye tracking techniques described herein detect and identify a reduction in reflection intensity due to transmission of laser light through the pupil and/or increased diffusivity of reflections from the cornea relative to reflections from the sclera. This effect is referred to herein as the “corneal shadow” effect. Laser eye tracking uses considerably less power than conventional camera-based eye tracking techniques. As a result, the laser eye tracking techniques described herein do not add significant power demands to a system and can be implemented in wearable heads-up displays without adding significant volume to the system battery.
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Citations
17 Claims
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1. A method of determining a gaze direction of a user, the method comprising:
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scanning a laser light over at least a portion of an eye of the user by a scanning laser device, wherein the portion of the eye of the user includes at least a portion of a cornea of the eye of the user; detecting reflections of the laser light from the eye by at least one photodetector; determining a relative intensity of each reflection by a processor; identifying, by the processor, at least one region of the eye that corresponds to a relatively low-intensity reflection; determining, by the processor, a position of the cornea based on the at least one region of the eye that corresponds to the relatively low-intensity reflection; and determining, by the processor, the gaze direction of the user based on the position of the cornea. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A laser eye tracker comprising:
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a scanning laser device to scan a laser light over at least a portion of an eye of a user, wherein the portion of the eye of the user includes at least a portion of a cornea of the eye of the user; at least one photodetector; a processor communicatively coupled to both the scanning laser device and the at least one photodetector; and a non-transitory processor-readable storage medium communicatively coupled to the processor, wherein the non-transitory processor-readable storage medium stores data and/or instructions that, when executed by the processor, cause; the at least one photodetector to detect reflections of the laser light from the eye; and the processor to; determine a relative intensity of each reflection; identify at least one region of the eye that corresponds to a relatively low-intensity reflection; determine a position of the cornea based on the at least one region of the eye that corresponds to the relatively low-intensity reflection; and determine a gaze direction of the user based on the position of the cornea. - View Dependent Claims (13, 14, 15, 16)
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17. A wearable heads-up display comprising:
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a support frame that in use is worn on a head of a user; a scanning laser device carried by the support structure, the scanning laser device including an infrared laser diode to output an infrared light and at least one visible light laser diode to output a visible light; a wavelength-multiplexed holographic optical element carried by the support frame and positioned within a field of view of at least one eye of the user when the support frame is worn on the head of the user, the wavelength-multiplexed holographic optical element aligned to receive both the infrared light and the visible light reflected from the scanning laser device and to redirect both the infrared light and the visible light towards the at least one eye of the user when the support frame is worn on the head of the user, wherein the wavelength-multiplexed holographic optical element includes a first hologram that is reflective of the visible light and transmissive of the infrared light and a second hologram that is reflective of the infrared light and transmissive of the visible light, and wherein the wavelength-multiplexed holographic optical element is substantially transparent to environmental light; an infrared photodetector carried by the support frame; a processor communicatively coupled to both the scanning laser device and the infrared photodetector; and a non-transitory processor-readable storage medium communicatively coupled to the processor, wherein the non-transitory processor-readable storage medium stores data and/or instructions that, when executed by the processor, cause; the scanning laser device to scan a laser light over at least a portion of an eye of the user, wherein the laser light includes infrared laser light and the portion of the eye of the user includes at least a portion of a cornea of the eye of the user; the at least one infrared photodetector to detect reflections of the infrared laser light from the eye; and the processor to; determine a relative intensity of each reflection; identify at least one region of the eye that corresponds to a relatively low-intensity reflection; determine a position of the cornea based on the at least one region of the eye that corresponds to the relatively low-intensity reflection; and determine a gaze direction of the user based on the position of the cornea.
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Specification