Noninvasive, remote eye position and orientation measurement system using light beams normal to the surface of the eye
First Claim
1. A process for generating physical signals representing the position and orientation of eyes comprising the steps of:
- (a) generating and directing light beams at surfaces of said eyes using a beam formation and directing means in combination with a plurality of photodetection means, such that each of said beams is reflected from said eye surface to a particular photodetection means within said plurality of photodetection means;
(b) directing each said beam so as to maximize the illumination of said particular photodetection means by reflection of said beam from an eye surface, a control signal for said directing of said beam being derived from an output signal from said photodetection means;
(d) estimating directions of at least six said beams from said output signals,(e) for at least six of said estimated beam directions, approximating a plane perpendicular to the eye surface at the reflection point of said beam as a plane through a central point of said beam formation means, parallel to said estimated direction, and parallel to a direction from said central point of beam formation to said particular photodetection means where said reflected illumination is maximized,at least three said planes being approximately perpendicular to said orbit surface of at least one eye and at least three said planes being approximately perpendicular to said corneal surface of said eye, and(f) approximating the optical axis of at least one said eye by a line which has minimized distances from said line to intersection points of triples of said planes perpendicular to said orbit surface of at least one eye and minimized distances from said line to intersection points of triples of said planes perpendicular to the corneal surface of said eye.
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Accused Products
Abstract
Photodetectors (18, 19) and light beam sources (10) are arranged near the field-of-regard (30) such that beams (12) are reflected from the viewer'"'"'s eyes back to the photodetectors. For each beam, the beam direction and a line between its source and a photodetector where its reflected signal is maximized determine a plane which is perpendicular to the occular surface at the point of reflection. Three such non-parallel planes on the orbit intersect at a point near center of a sphere (14) approximating the orbit surface. Three non-parallel planes perpendicular to the cornea intersect near the center (34) of a sphere (16) approximating the corneal surface. A processor (26) operating on detector outputs determines coordinates of the optical axis (36) as the unique line passing through the center (32) and the center (34), as well as coordinates of these centers from which eye position can then be derived. From one or both optical axes, the line-of-sight can be determined. Line-of-sight parameters can be used, for example, to select options on a computer or television screen by staring at them and blinking or otherwise indicating the selection.
18 Citations
15 Claims
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1. A process for generating physical signals representing the position and orientation of eyes comprising the steps of:
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(a) generating and directing light beams at surfaces of said eyes using a beam formation and directing means in combination with a plurality of photodetection means, such that each of said beams is reflected from said eye surface to a particular photodetection means within said plurality of photodetection means; (b) directing each said beam so as to maximize the illumination of said particular photodetection means by reflection of said beam from an eye surface, a control signal for said directing of said beam being derived from an output signal from said photodetection means; (d) estimating directions of at least six said beams from said output signals, (e) for at least six of said estimated beam directions, approximating a plane perpendicular to the eye surface at the reflection point of said beam as a plane through a central point of said beam formation means, parallel to said estimated direction, and parallel to a direction from said central point of beam formation to said particular photodetection means where said reflected illumination is maximized, at least three said planes being approximately perpendicular to said orbit surface of at least one eye and at least three said planes being approximately perpendicular to said corneal surface of said eye, and (f) approximating the optical axis of at least one said eye by a line which has minimized distances from said line to intersection points of triples of said planes perpendicular to said orbit surface of at least one eye and minimized distances from said line to intersection points of triples of said planes perpendicular to the corneal surface of said eye. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A process for generating physical signals representing the position and orientation of eyes comprising the steps of:
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(a) generating and forming spatially shaped or structured light beams and detecting reflections of said light beams using means including beam generation and shaping means, light source means, beam directing means, a plurality of photodetection means, and means to generate output signals from each said photodetection means, (b) deriving a control signal for directing of each said beam from an output signal from said specific photodetection means; (c) using said control signal to direct each said beam at said eye surface such that said beam is reflected from said surface to a specific photodetection means among said plurality of photodetection means so as to maximize the reflected light intensity at said specific photodetection means, (d) directing at least six said beams maximizing said output signals so that at least three said beams are reflecting from said orbit of at least one of said eyes and at least three said beams are reflecting from a cornea of said eye, (e) for each of said six beams, approximating a plane perpendicular to the eye surface at the reflection point of said beam by a plane passing through said beam formation means, parallel to an estimated direction of said beam, and parallel to a line through said beam formation means and said specific photodetection means where intensity of said reflected beam is maximized, (f) approximating the optical axis of at least one said eye by a line which passes through a specified neighborhood of intersection points of triples of said planes approximating planes perpendicular to said orbit surface of at least one eye and minimized distances from said line to intersection points of triples of said planes approximating planes perpendicular to the corneal surface of said eye. - View Dependent Claims (9, 10)
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11. A process for generating physical signals representing the position and orientation of eyes comprising the steps of:
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(a) generating light beams by light source means in combination with beam formation means and beam directing means (b) directing light beams at surfaces of said eyes using said beam directing means, such that each of said beams is reflected from an eye surface to a particular photodetection means among a plurality of photodetection means, (c) controlling the direction of said beam so as to maximize the illumination of said particular photodetection means resulting from reflection of said beam from an eye surface, a control signal for control of said beam being derived from an output signal from said particular photodetection means; (d) measuring direction of said beam outgoing from beam formation means of a specified minimum number of said beams, (e) measuring arrival angle at said particular photodetection means of said beam after reflection from said eye surface, (f) for each of said controlled beams with maximized illumination at a particular photodetection means, estimating parameters determining a line perpendicular to the eye surface at the reflection point of said beam as the angular bisector of said beam'"'"'s outgoing direction and reflected direction, at least one said line being approximately perpendicular to said corneal surface of at least one of said eyes visible between the eyelids and at one said line being approximately perpendicular to the orbit surface surrounding said cornea and visible between the eyelids, and (f) approximating the optical axis of at least one said eye by a line which has minimized distances from said line to said lines perpendicular to said orbit surface and from said line to said lines perpendicular to said corneal surface. - View Dependent Claims (12, 13, 14, 15)
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Specification