Eye Tracking System

Abstract

A system evaluates a point of gaze of a user on an object and includes at least one eye tracker camera and at least one positioning camera. The eye tracker camera and the positioning camera are arranged in fixed positions relative to each other. A light source provides corneal reflection from at least one of a user's eyes. A computer and an object is provided. Geometrical data of the object enables determination of the position of at least one screen in a first 3D coordinate system. The computer is configured to determine a gaze line of the user relative to a second 3D coordinate system; the position of the screen relative to a third 3D coordinate system; a gaze point calculated as the intersection of the gaze line with the surface of the screen in a fourth 3D coordinate system; and the location of the gaze point on the screen.

1 . A system for tracking the location of a point of gaze of a user on at least one screen, said system comprising:
 at least one eye tracker camera and at least one positioning camera, said at least one eye tracker camera and said at least one positioning camera are configured to be arranged in fixed positions relative to each other;   at least one light source configured to provide corneal reflection from at least one eye of said user;   at least one computer; and   at least one monitor comprising a screen, wherein geometrical data of said at least one monitor is stored in a storage device accessible to said at least one computer;   wherein said geometrical data comprises data that enables determination of the position of at least one of said at least one screen in a first 3D coordinate system;   wherein any combination of said at least one computer is configured to determine:   (a) a gaze line of said user relative to a second 3D coordinate system, based on at least one image received from said at least one eye tracker camera;   (b) the position of said at least one screen relative to a third 3D coordinate system, based on an image received from said at least one positioning camera;   (c) a gaze point calculated as the intersection of said gaze line with the surface of said screen in a fourth 3D coordinate system, based on said gaze line, said at least one screen position and said at least one monitor geometrical data; and   (d) the location of said gaze point on said at least one screen;   
       wherein any coordinate system of said first, second, third and fourth 3D coordinate systems may be the same coordinate system as any other of said first, second, third and fourth 3D coordinate systems. 
     
     
         2 . The system of  claim 1 , wherein said at least one screen comprises at least two screens; said at least two screens are configured to be arranged in fixed positions relative to each other. 
     
     
         3 . The system of  claim 1 , wherein said at least one monitor is configured to display at least one marker. 
     
     
         4 . The system of  claim 1 , wherein said at least one positioning camera comprises at least two positioning cameras; said at least two positioning cameras are configured to enable determining the position of said at least one monitor using stereoscopic methods. 
     
     
         5 . The system of  claim 1 , wherein said at least one monitor comprises at least two monitors; said at least two monitors can be arranged in any positions relative to each other, said arranged positions can be changed. 
     
     
         6 . The system of  claim 1 , wherein said at least one of said first, second, third and fourth 3D coordinate systems is one of:
 a. a coordinate system defined relative to one of said at least one eye tracker camera;   b. a coordinate system defined relative to one of said at least one positioning camera; and   c. a coordinate system defined relative to one of said at least one monitor.   
     
     
         7 . A system for evaluating a point of gaze of a user on an object, said system comprising:
 an eye tracker, comprising:   at least one eye tracker camera associated with a first 3D coordinate system that is fixed relative to said at least one eye tracker camera;   a light source configured to provide conical reflection from at least one eye of said user; and   at least one computer;   at least one positioning camera associated with a second 3D coordinate system that is fixed relative to said at least one positioning camera; and   at least one object, wherein geometrical data of said at least one object is stored in a storage device accessible to the at least one computer;   wherein any combination of said at least one computer is configured to determine:   (a) a gaze line of said user relative to said first 3D coordinate system, based on an image received from said at least one eye tracker camera;   (b) the position of said at least one eye tracker camera relative to said second 3D coordinate system, thereby determining the position of one 3D coordinate system in the other 3D coordinate system, based on an image received from said at least one positioning camera;   (c) the position of said at least one object relative to said second 3D coordinate system based on said image from said at least one positioning camera and said stored geometrical data of said at least one object; and   (d) a gaze point calculated as the intersection of said gaze line with a surface of said object in any 3D coordinate system, based on said gaze line in said any 3D coordinate system and at least one position of said at least one object in said any 3D coordinate system.   
     
     
         8 . The system of  claim 7 , wherein said at least one object comprises at least two objects; wherein said at least two objects are configured to be arranged in fixed positions relative to each other. 
     
     
         9 . The system of  claim 7 , wherein said at least one object is a monitor, said monitor is configured to display at least one marker. 
     
     
         10 . The system of  claim 7 , wherein said at least one positioning camera comprises at least two positioning cameras; said at least two positioning cameras are configured to enable determining the position of said at least one object using stereoscopic methods. 
     
     
         11 . A method for calibrating an eye tracker, said method comprising the steps of:
 drawing the attention of a user to a calibration target;   employing at least one positioning camera and at least one computer thereby determining the position of said calibration target and an eye tracker coordinate system relative to each other;   determining calibration parameters of a gaze line, to said calibration target, in a first coordinate system;   repeating the above steps thereby providing a desired part of a gaze range and calibration targets distribution; and   storing calibration data.   
     
     
         12 . The method of  claim 11 , wherein said calibration target comprises at least one LED. 
     
     
         13 . The method of  claim 12 , wherein drawing the attention of said user comprises turning ON at least one of said at least one LED of a desired target and turning OFF other LEDs of other targets. 
     
     
         14 . The method of  claim 12 , wherein a target is distinguished by any of an ON/OFF sequence pattern, a color and a shape defined by its at least one LED. 
     
     
         15 . The method of  claim 14 , wherein said shape of a target is determined by an arrangement of said at least one LED constituting said target, said arrangement comprises any of a spatial distribution, an ON/OFF sequence and a color. 
     
     
         16 . The method of  claim 11 , wherein said calibration target comprises items. 
     
     
         17 . The method of  claim 16 , wherein drawing the attention of said user comprises illuminating an item of a desired target. 
     
     
         18 . The method of  claim 16 , wherein targets are distinguished by any of an ON/OFF sequence pattern of illumination, a color and a shape. 
     
     
         19 . The method of  claim 11 , wherein said target is projected on a substrate using at least one projector. 
     
     
         20 . The method of  claim 16 , wherein drawing the attention of said user comprises projecting a desired target. 
     
     
         21 . The method of  claim 20 , wherein targets are distinguished by any of an ON/OFF sequence pattern of the projector, an image color and an image shape. 
     
     
         22 . The method of  claim 11 , wherein after said calibration, said eye tracker position is changed so that at least one target falls in a position, in said gaze range, that did not have a target during said calibration; said method further comprises:
 repeating said calibration steps using said at least one target.   
     
     
         23 . The method of  claim 11 , wherein said at least one positioning camera is configured to capture at least a part of said targets. 
     
     
         24 . The method of  claim 11 , wherein a computer is configured to determine the position of at least one target that is not captured by said positioning camera, and said eye tracker coordinate system relative to each other, based on at least one image received from said at least one positioning camera and data of the spatial arrangement of at least a part of the targets that includes at least a part of the targets captured by said at least one positioning camera and said at least one target that is not captured by said at least one positioning camera.