Eye tracking system and method

• US 5,345,281 A
• Filed: 12/17/1992
• Issued: 09/06/1994
• Est. Priority Date: 12/17/1992
• Status: Expired due to Fees

• Current Assignee: John Taboada, William Robinson
• Original Assignee: John Taboada, William Robinson
• Inventors: Robinson, William, Taboada, John
• Primary Examiner(s): Sikes, William L.
• Assistant Examiner(s): Dang, Hung Xuan
• Application Number:
  US07/992,182
• Time in Patent Office: 628 Days
• Field of Search: 351/210, 351/209, 351/221, 351/220, 351/200, 351/201, 351/246
• US Class Current: 351/210
• CPC Class Codes: A61B 3/113 for determining or recording eye movement
• CPC Class Codes: A61B 3/156 for blocking
• CPC Class Codes: G06V 40/19 Sensors therefor

Abstract

System and method for tracking the gaze of the human eye are described which comprise directing an infrared light beam along an optical axis into the eye, and displaying the reflected optical light distribution on a position sensing detector to determine eye position, considering the differences in infrared reflectivities between the pupil and the surrounding iris and sclera.

Claims

1. A system for measuring the angular gaze position of the human eye, comprising:

(a) a source of infrared light;

(b) first optical means for directing a light beam from said source along a first optical axis into an eye of a subject;

(c) dichroic beamsplitter means disposed along said first optical axis for simultaneously directing said light beam into said eye and transmitting into said eye visual images along a viewing axis of said eye;

(d) second optical means for directing a reflected beam from said eye along a second optical axis and for forming an image of the pupil and surrounding iris and sclera of said eye, said image comprising a bright spot defining said pupil surrounded by a dark region defining said iris and sclera; and

(e) two-dimensional light position sensing means disposed along said second optical axis for detecting the position of said dark spot relative to said second optical axis and for providing a signal corresponding to the position of said pupil relative to said first optical axis.

2. The system of claim 1 further comprising directing means controllable by said signal from said two-dimensional light position sensing means for controllably directing said light beam into said eye.

3. The system of claim 2 wherein said directing means includes a microprocessor controller with analog-to-digital converter and microcomputer for providing signals for controllably directing said light beam into said eye.

4. The system of claim 3 further comprising means for displaying the position of said pupil.

5. The system of claim 1 wherein said source of infrared light is selected from the group consisting of a gallium arsenide light emitting diode and a laser source.

6. The system of claim 1 wherein said dichroic beamsplitter means is a polarizing type disposed to reflect one of the vertically and horizontally polarized light of said light beam from said source and to transmit the other of said vertically and horizontally polarized light of said light beam.

7. The system of claim 1 wherein said two-dimensional position sensing means comprises a two-axis position sensitive photo detector.

8. A system for tracking the gaze of the human eye, comprising:

(a) a source of infrared light;

(b) first optical means for directing a light beam from said source along a first optical axis into an eye of a subject, said first optical means including dichroic beamsplitter means disposed along said first optical axis and alignable with the pupil of said eye and along a viewing axis of said eye for simultaneously directing said light beam into said eye and transmitting into said eye visual images along said viewing axis;

(c) second optical means for directing a reflected beam from said eye along a second optical axis and for forming an image of the pupil and surrounding iris and sclera of said eye, said image comprising a dark spot defining said pupil surrounded by a bright region defining said iris and sclera; and

(d) two-dimensional position sensing means disposed along said second optical axis for detecting the position of said dark spot relative to said second optical axis and for providing a signal corresponding to the position of said pupil relative to said first optical axis.

9. The system of claim 8 wherein said source of infrared light is selected from the group consisting of a gallium arsenide light emitting diode and a laser source.

10. The system of claim 8 wherein said dichroic beamsplitter means is a polarizing type disposed to reflect one of the vertically and horizontally polarized light of said light beam from said source and to transmit the other of said vertically and horizontally polarized light of said light beam.

11. The system of claim 8 wherein said infrared light is polarized, and further comprising filter means for filtering from said reflected beam light corresponding to reflections from said iris and sclera.

12. The system of claim 8 wherein said two-dimensional position sensing means comprises a two-axis position sensitive photo detector.

13. The system of claim 8 further comprising directing means controllable by said signal from said two-dimensional light position sensing means for controllably directing said light beam into said eye, said directing means including a microprocessor controller with analog-to-digital converter and microcomputer for providing signals for controllably directing said light beam into said eye.

14. A system for two-dimensional control of cursor position on a computer video display using eye movement, comprising:

(a) a source of infrared light;

(b) first optical means for directing a light beam from said source along a first optical axis into an eye of a subject, said first optical means including dichroic beamsplitter means disposed along said first optical axis and alignable with the pupil of said eye along a viewing axis of said eye for simultaneously directing said light beam into said eye and transmitting into said eye visual images along said viewing axis;

(c) second optical means for directing a reflected beam from said eye along a second optical axis and for forming an image of the pupil and surrounding iris and sclera of said eye, said image comprising a dark spot defining said pupil surrounded by a bright region defining said iris and sclera;

(d) two-dimensional position sensing means disposed along said second optical axis for detecting the position of said dark spot relative to said second optical axis and for providing a signal corresponding to the position of said pupil relative to said first optical axis; and

(e) electronic means for receiving said signal and for displaying said signal as a cursor position on a computer video display corresponding to the position of said pupil relative to said viewing axis of said eye.

15. The system of claim 14 wherein said dichroic beamsplitter means is a polarizing type disposed to reflect one of the vertically and horizontally polarized light of said light beam from said source and to transmit the other of said vertically and horizontally polarized light of said light beam.

16. A system for two-dimensional control of cursor position on a computer video display using eye movement, comprising:

(a) a source of infrared light comprising first and second infrared light emitting diodes;

(b) first optical means for directing first and second light beams from corresponding said first and second light emitting diodes into an eye of a subject, said first optical means including polarizing filter means for identically polarizing said first and second light beams and including dichroic beamsplitter means alignable with the pupil of said eye along a viewing axis of said eye for simultaneously directing said first and second light beams into said eye and transmitting into said eye visual images along said viewing axis;

(c) second optical means for directing a reflected beam from said eye along an optical axis and for forming an image of the pupil and surrounding iris and sclera of said eye, said image comprising a dark spot defining said pupil surrounded by a bright region defining said iris and sclera;

(d) two-dimensional position sensing means disposed along said optical axis for detecting the position of said dark spot relative to said second optical axis and for providing a signal corresponding to the position of said pupil relative to said viewing axis; and

(e) electronic means for receiving said signal and for displaying said signal as a cursor position on a computer video display corresponding to the position of said pupil relative to said viewing axis of said eye.

17. A method for tracking the gaze of the human eye, comprising the steps of:

(a) providing a source of infrared light;

(b) directing a light beam from said source along a first optical axis into an eye of a subject, utilizing first optical means including dichroic beamsplitter means disposed along said first optical axis and alignable with the pupil of said eye and along a viewing axis of said eye for simultaneously directing said light beam into said eye and,transmitting into said eye visual images along said viewing axis;

(c) directing a reflected beam from said eye along a second optical axis utilizing second optical means for forming an image of the pupil and surrounding iris and sclera of said eye, said image comprising a dark spot defining said pupil surrounded by a bright region defining said iris and sclera; and

(d) detecting the position of said dark spot relative to said second optical axis corresponding to the position of said pupil relative to said first optical axis.

18. The method of claim 17 wherein said dichroic beamsplitter means is a polarizing type disposed to reflect one of the vertically and horizontally polarized light of said light beam from said source and to transmit the other of said vertically and horizontally polarized light of said light beam.