EYE GAZE TRACKING

• US 20110182472A1
• Filed: 07/08/2008
• Published: 07/28/2011
• Est. Priority Date: 07/08/2008
• Status: Active Grant

• Current Assignee: ITU Business Development
• Original Assignee: ITU Business Development
• Inventors: Hansen, Dan Witzner
• Granted Patent: US 9,398,848 B2
• Time in Patent Office: Days
• US Class Current: 382/103
• CPC Class Codes: A61B 3/113 for determining or recording eye movement
• CPC Class Codes: G02B 27/0093 with means for monitoring data relating to the user, e.g. head-tracking, eye-tracking
• CPC Class Codes: G06F 3/011 Arrangements for interaction with the human body, e.g. for user immersion in virtual reality blind teaching G09B21/00
• CPC Class Codes: G06F 3/013 Eye tracking input arrangements G06F3/015 takes precedence
• CPC Class Codes: G06F 3/0325 using a plurality of light emitters or reflectors or a plurality of detectors forming a reference frame from which to derive the orientation of the object, e.g. by triangulation or on the basis of reference deformation in the picked up image
• CPC Class Codes: G06T 7/70 Determining position or orientation of objects or cameras camera calibration G06T7/80
• CPC Class Codes: G06V 40/19 Sensors therefor
• CPC Class Codes: H04N 13/383 for tracking with gaze detection, i.e. detecting the lines of sight of the viewer's eyes

Abstract

This invention relates to a method of performing eye gaze tracking of at least one eye of a user, by determining the position of the center of the eye, said method comprising the steps of:

• • detecting the position of at least three reflections on said eye,
  • transforming said positions to spanning a normalized coordinate system spanning a frame of reference, wherein said transformation is performed based on a bilinear transformation or a non linear transformation e.g. a möbius transformation or a homographic transformation,
  • detecting the position of said center of the eye relative to the position of said reflections and transforming this position to said normalized coordinate system,
    tracking the eye gaze by tracking the movement of said eye in said normalized coordinate system.

Thereby calibration of a camera, such as knowledge of the exact position and zoom level of the camera, is avoided. Further, it is not necessary to know the position of light sources. This results in a much more flexible and user friendly system.

Claims

1. A method of performing eye gaze tracking of at least one eye of a user, by determining the position of the central eye, said method comprising the steps of:

detecting the position of at least three reflections on said eye,

transforming said positions to spanning a normalized coordinate system spanning a frame of reference,

detecting the position of said central eye relative to the position of said reflections and transforming this position to said normalized coordinate system,

tracking the eye gaze by tracking the movement of said eye in said normalized coordinate system.

2. A method according to claim 1, wherein said reflections are obtained by projecting light sources towards said at least one eye of said user.

3. A method according to claim 1-2, wherein the step of transforming said positions to spanning a normalized coordinate system is performed using a bilinear transformation function.

4. A method according to claim 1-3, wherein the eye gaze is tracked to determine towards which points on a surface said user is gazing.

5. A method according to claim 1-4, wherein said surface is a screen surface on a monitor.

6. A method according to claim 1-5, wherein mapping between the eye gazing and said surface coordinates is obtained via a calibration process where the user is requested to look at a number of predefined points on said surface.

7. A computer-readable medium having stored therein instructions for causing a processing unit to execute a method according to claims 1-6.

8. A system for performing eye gaze tracking of at least one eye of a user, by determining the position of the central eye, said method comprising the steps of:

means for detecting the position of at least three reflections on said eye,

means for transforming said positions to spanning a normalized coordinate system spanning a frame of reference,

means for detecting the position of said central eye relative to the position of said reflections and transforming this position to said normalized coordinate system,

means for tracking the eye gaze by tracking the movement of said eye in said normalized coordinate system.