Gaze tracking system and method

• US 6,637,883 B1
• Filed: 01/23/2003
• Issued: 10/28/2003
• Est. Priority Date: 01/23/2003
• Status: Active Grant

• Current Assignee: Hemant V. Tengshe, Venkatesh G. Tengshe, Vishwas V. Tengshe
• Original Assignee: Hemant V. Tengshe, Venkatesh G. Tengshe, Vishwas V. Tengshe
• Inventors: Tengshe, Vishwas V., Tengshe, Venkatesh G., Tengshe, Hemant V.
• Primary Examiner(s): MANUEL, GEORGE C
• Application Number:
  US10/349,435
• Time in Patent Office: 278 Days
• Field of Search: 351/209, 351/210, 382/103, 345/7, 345/8, 345/9, 600/426, 600/417, 600/429
• US Class Current: 351/210
• CPC Class Codes: A61B 3/113 for determining or recording eye movement
• CPC Class Codes: G06F 3/013 Eye tracking input arrangements G06F3/015 takes precedence
• CPC Class Codes: G06V 40/19 Sensors therefor

Abstract

An eye-tracking system for displaying a video screen pointer at a point of regard of a user'"'"'s gaze. The system comprises a camera focused on the user'"'"'s eye; a support connected to the camera for fixing the relative position of the camera to the user'"'"'s pupil; a computer having a CPU, memory, video display screen, an eye-tracking interface, and computer instructions for: segmenting the digital pixel data of the image of the eye into black and white sections based upon user selectable RGB threshold settings; determining the center of the eye based upon the segmented digital data; mapping the determined center of the eye to a pair of coordinates on the video screen; and displaying a pointer on the video display screen at the point of the regard. The processing performed by the computer includes a fine-tuning capability for positioning the cursor at point on the video screen substantially overlapping the point of regard, and a gaze activated method for selecting computer actions. The system includes additional user mounted sensors for determining the axial position of the camera, thereby compensating for inadvertent eye movement when the point of regard has not changed.

Claims

1. An eye-tracking system for tracking the point of regard of a user'"'"'s gaze comprising:

camera means for acquiring a video image of the user'"'"'s eye;

support means, connected to the camera means, for fixing the relative physical positions of the camera means;

video digitizing means, connected to the camera means, for accepting the video image of the user'"'"'s eye and converting the video image to a digital image;

computer means electrically connected to the video digitizing means, further comprising a central processing unit, a memory, a video display screen, eye-tracking interface, and computer readable program code means stored in the memory, wherein the code means further comprising;

first instruction means for determining the center of the user'"'"'s eye within the digital image;

second instruction means for correlating the determined center of the user'"'"'s eye to a point of regard on the display screen;

third instruction means for accepting the correlated data and placing a display screen pointer at a position on the display screen substantially overlapping the point of regard; and

fourth instruction means for providing the user with a display screen menu activated by eye movement;

fifth instruction means for selecting RGB pixel intensity threshold values for the digital image;

sixth instruction means for segregating the digital pixel data into two separate binary groups as first and second groups using the RGB threshold values as a discriminator; and

seventh instruction means for substantially determining the position of the center of the eye in accordance with the segregated pixel data and the axial position of the support means;

whereby the eye-tracking system positions a pointer on the video screen at the point of regard of the user'"'"'s gaze and provides the user with an eye movement activated method for selecting computer-programmable activities.

2. The system of claim 1, wherein the code means further comprises:

eighth instruction means for storing to memory a map correlating a substantial portion of a display screen coordinate space to a pre-determined position of the center of the user'"'"'s eye, thereby facilitating the positioning of the display screen pointer;

ninth instruction means for using eye movement to fine-tune the position of the display screen pointer; and

tenth instruction means for performing user defined actions based upon the length of time a user has locked their gaze upon a point of regard.

3. The system of claim 1, wherein the support means substantially fixes the position of the user'"'"'s eye relative to the camera.

4. The system of claim 1, further comprising a light source disposed on the support means, whereby the center of the user'"'"'s is illuminated.

5. An eye-tracking system for tracking the point of regard of a user'"'"'s gaze comprising:

camera means for acquiring a video image of the user'"'"'s eye;

support means, connected to the camera means, for fixing the relative physical positions of the camera means;

compass and level sensing means for acquiring axial position data for the support means;

video digitizing means, connected to the camera means, for a accepting the video image of the user'"'"'s eye and converting the video image to a digital image;

computer means electrically connected to the video digitizing means and attitude sensor means, further comprising a central processing unit, eye-tracking interface, a memory, a video display screen, and computer readable program code means stored in the memory, wherein the code means further comprising;

first instruction means for determining the center of the user'"'"'s eye within the digital image;

second instruction means for correlating the determined center of the user'"'"'s eye and the axial position of the attitude sensors to a point of regard on the display screen;

third instruction means for accepting the correlated data and placing a display screen pointer at a position on the display screen substantially overlapping the point of regard; and

fourth instruction means for providing the user with a display screen menu activated by eye movement;

whereby the eye-tracking system positions a pointer on the video screen at a point of regard of the user'"'"'s gaze, and provides the user with an eye movement activated method for selecting actions relative to the point of regard.

6. A computer useable medium having computer readable program code means embodied thereon, the computer readable program code means comprising:

first instruction means for selecting an image coordinate space of the eye;

second instruction means for determining RGB threshold values in accordance with a user selected representation of the digital pixel data corresponding to the selected image space;

third instruction means for segregating the digital pixel data into two separate binary groups as first and second groups using the RGB threshold values as a discriminator; and

fourth instruction means for determining the logical position of the center of the eye within the image space in accordance with the segregated data.

7. The computer medium of claim 6, wherein the code means further comprises:

fifth instruction means for processing horizontal and vertical position data relative to the source of the image coordinate space of the eye;

sixth instruction means for mapping the logical position of the center of the user'"'"'s eye from the image space into a position within a coordinate space of the video display;

seventh instruction means for accepting data corresponding to the determined position of the center of the eye and placing a cursor at the pre-determined position on the display screen;

eighth instruction means for fine-tuning the position of the cursor on the display screen;

the instruction means to determine the length of time a user locks their gaze upon a point of regard; and

tenth instruction means for performing user defined actions based upon the length of time a user locks their gaze upon a point of regard.