US 4,836,670 A · Eye movement detector

Abstract

A system for eye movement detection is disclosed that utilizes an infrared light emitting diode mounted coaxially in front of the lens of an infrared sensitive video camera for remotely making images of the eye of a computer operator. The reflected light causes bright eye effect which outlines the pupil as brighter than the rest of the eye and also causes an even brighter small glint from the surface of the cornea. The computer includes graphic processing which takes a video image, digitizes it into a matrix of pixels and analyzes the matrix. Using special algorithms the analysis determines the location of the pupil's center and the location of the glint relative to each other and with this information determines where the eye is gazing. If the eye-gaze is for a predetermined time at images in selected areas on the computer screen, the area is selected and results in actuation of other devices or the presentation of additional images on the screen. This is especially useable for handicapped persons to control their environment. Other uses include operator interfacing with workstations, cockpit controls and in industrial environments.

Claims31

Dependent claims

An eye movement detector comprising:

a display to be viewed by an operator;
a camera with a lens located near said display and directed in a manner to obtain an image of an operator's eye when the display is being viewed;
a small illuminator mounted in front of said camera lens and not further from the axis of said lens than one-half the distance from the center of said lens and the edge thereof and out of said lens' focus directed towards the position of an operator's eye so that the reflected illumination causes the operator's pupil to be brighter than the surrounding part of the eye due to the bright eye effect;
and
a computer for analyzing the image of an operator's eye to determine the center of the pupil and utilize said information to detect the eye position and correlate said position with whether or not the operator is gazing at the display.

2 more elements

An eye movement detector comprising:

a display having multiple individual areas representing different choices that can be made by an operator when viewed by an operator for a predetermined interval of time;
a camera with a lens located near said display and directed in a manner to obtain an image of an operator's eye when the display is being viewed;
an illuminator directing an infrared source of illumination coaxial with said camera lens towards the position of an operator's eye so that the reflected illumination causes the operator's pupil to be brighter than the surrounding part of the eye due to the bright eye effect and also causes a glint reflection from the cornea of the eye;
a computer for analyzing said image of an illuminated operator's eye to determine the center of the pupil and location of the glint and utilizing said information in determining the eye-gaze point and correlating said eye-gaze point with whether or not the operator is gazing at an individual area of the display;
and
said computer analysis including using said image of the operator's eye in a digitized matrix of pixels that is first analyzed by scanning a selected sampling of pixels, which may include every pixel or some lesser number of pixels, and determining with respect to each scanned pixel the light intensity value of the pixel and the frequency of occurrence of each pixel having the same intensity and making a determination of the pupil intensity threshold by determining the minimum number of occurrences of pixel intensity of the same value between the pixel intensity represented by the pupil and the pixel intensity represented by the part of the eye and face surrounding the pupil and also determining the glint intensity threshold by finding the pixel intensity level between the maximum intensity of pixels representing the pupil and the minimum intensity of the pixels representing the glint.

3 more elements

A method for determining eye-gaze comprising the follows steps:

placing on a display multiple individual areas representing different choices that can be made by an operator when viewed by an operator for a predetermined interval of time;
obtain an image of an operator's eye by a camera with a lens located near the display and when the display is being viewed;
illuminate the operator's eye by directing an infrared source of illumination coaxial with said camera lens towards the position of an operator's eye so that the reflected illumination causes the operator's pupil to be brighter than the surrounding part of the eye due to the bright eye effect and also causes a glint reflection from the cornea of the eye;
analyze said image of the operator's eye to determine the center of the pupil and location of the glint and utilize said information to determine the eye-gaze point and correlate said eye-gaze point with whether or not the operator is gazing at an individual area of the display;
and
using said image of the operator's eye to produce a digitized matrix of pixels that is first analyzed by scanning a selected sampling of pixels, which may include every pixel or some lesser number of pixels, and determine with respect to each scanned pixel the light intensity value of the pixel and the frequency of occurrence of each pixel having the same intensity and make a determination of the pupil intensity threshold by determining the minimum number of occurrences of pixel intensity of the same value between the pixel intensity represented by the pupil and the pixel intensity represented by the part of the eye and face surrounding the pupil and also determine the glint intensity threshold by finding the pixel intensity level between the maximum intensity of pixels representing the pupil and the minimum intensity of the pixels representing the glint.

3 more elements

Dependencies are inferred from the claim text.

Eye movement detector

Life of this patent

Eye movement detector

Life of this patent

Abstract

Claims31