EYE GAZE TRACKING APPARATUS, IMAGING APPARATUS, EYE GAZE TRACKING METHOD, PROGRAM, AND INTEGRATED CIRCUIT

• US 20100204608A1
• Filed: 05/20/2009
• Published: 08/12/2010
• Est. Priority Date: 05/20/2008
• Status: Active Grant

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Sugio, Toshiyasu, Sato, Daisuke
• Granted Patent: US 8,419,654 B2
• Time in Patent Office: Days
• US Class Current: 600/558
• CPC Class Codes: A61B 3/113 for determining or recording eye movement
• CPC Class Codes: G06V 40/19 Sensors therefor

Abstract

An eye gaze tracking apparatus (100) includes: an electro-oculogram measuring unit that outputs an electro-oculogram original signal; a calibration index presenting unit (103) that presents a calibration index to a user; a saccade detection unit (104) that outputs an electro-oculogram change amount that is an amount of change in an electro-oculogram before or after a saccadic movement which is measured when a gaze-path position of the user moves to the calibration index; a calibration parameter calculating unit (105) that calculates a calibration parameter based on a position of the calibration index and an electro-oculogram change amount; and a calibration unit (101) that detects the gaze-path direction of the user from the electro-oculogram original signal.

Claims

1. An eye gaze tracking apparatus which detects a gaze-path direction of a user from an electro-oculogram, said eye gaze tracking apparatus comprising:

an electro-oculogram measuring unit configured to measure the electro-oculogram resulting from an eye movement, and to output an electro-oculogram original signal;

a calibration index presenting unit configured to present a calibration index to the user;

a saccade detection unit configured to detect a saccadic movement from the electro-oculogram original signal, and to output an electro-oculogram change amount, the saccadic movement being a rapid eyeball movement which occurs when a gaze-point of the user moves to the calibration index presented by said calibration index presenting unit, and the electro-oculogram change amount being an amount of change in the electro-oculogram before or after the saccadic movement;

a calibration parameter calculating unit configured to calculate a calibration parameter based on a position of the calibration index presented by said calibration index presenting unit and the electro-oculogram change amount that has been output from said saccade detection unit; and

a calibration unit configured to detect the gaze-path direction of the user from the electro-oculogram original signal based on the calibration parameter.

2. The eye gaze tracking apparatus according to claim 1,

wherein said saccade detection unit includes:

a delay signal generation unit configured to delay the electro-oculogram original signal for a predetermined amount of time and output a delay signal;

a subtraction unit configured to generate an output signal obtained by subtracting the delay signal from the electro-oculogram original signal; and

a saccade determining unit configured to determine that a signal exceeding a predetermined threshold in the output signal is a saccade signal that indicates the saccadic movement.

3. The eye gaze tracking apparatus according to claim 2,

wherein the predetermined amount of time of the delay is smaller than an amount of time of fixation by the user on the calibration index.

4. The eye gaze tracking apparatus according to claim 1,

wherein said saccade detection unit includes:

a first filtering unit configured to output a first electro-oculogram signal by performing one of maximum value filtering and minimum value filtering, on the electro-oculogram original signal;

a subtraction unit configured to subtract one of the first electro-oculogram signal and a second electro-oculogram signal from the other, the second electro-oculogram signal being obtained from the electro-oculogram original signal; and

a saccade determining unit configured to determine that a signal exceeding a predetermined threshold among the output signals is a saccade signal that indicates the saccadic movement.

5. The eye gaze tracking apparatus according to claim 4,

wherein said saccade detection unit further includes a second filtering unit configured to output the second electro-oculogram signal by performing the other one of the maximum value filtering and the minimum value filtering, on the electro-oculogram original signal.

6. The eye gaze tracking apparatus according to claim 4,

wherein said saccade detection unit further includes a second filtering unit configured to output the second electro-oculogram signal by performing the other one of the maximum value filtering and the minimum value filtering, on the first electro-oculogram signal.

7. An eye gaze tracking apparatus according to claim 1,

wherein said calibration index presenting unit is configured to present a first calibration index to the user in response to receiving a calibration parameter update instruction, and then present a second calibration index at a position different from a position of the first calibration index in response to the detection of the saccadic movement by said saccade detection unit, and

said saccade detection unit is configured to output, to said calibration parameter calculating unit, the electro-oculogram change amount which is measured when the gaze-point of the user moves from the first calibration index to the second calibration index.

8. The eye gaze tracking apparatus according to claim 7,

wherein said calibration parameter calculating unit is configured to determine, as the calibration parameter, a value resulting from dividing the electro-oculogram change amount that has been output from said saccade detection unit, by an eyeball movement angle which is measured when the gaze-point of the user moves from the first calibration index to the second calibration index.

9. The eye gaze tracking apparatus according to claim 7,

wherein the calibration parameter is a table holding a plurality of combinations of an eyeball movement angle which is measured when the gaze-point of the user moves from the first calibration index to the second calibration index and the electro-oculogram change amount that corresponds to the eyeball movement angle.

10. An imaging apparatus which performs imaging in a gaze-path direction of a user, said apparatus comprising:

an imaging unit;

an eye gaze tracking apparatus according to claim 1; and

an image control unit configured to cause said imaging unit to image a gaze-path direction detected by said calibration unit.

11. An eye gaze tracking method for detecting a gaze-path direction of a user from an electro-oculogram,

said eye gaze tracking method comprising:

measuring an electro-oculogram resulting from an eye movement, and outputting an electro-oculogram original signal;

presenting a calibration index to the user;

detecting a saccadic movement from the electro-oculogram original signal, and outputting an electro-oculogram change amount, the saccadic movement being a rapid eyeball movement which occurs when a gaze-point of the user moves to the calibration index presented in said presenting a calibration index, and the electro-oculogram change amount being an amount of change in the electro-oculogram before or after the saccadic movement;

calculating a calibration parameter based on a position of the calibration index presented in said presenting a calibration index and the electro-oculogram change amount that has been output in said detecting a saccadic movement; and

detecting the gaze-path direction of the user from the electro-oculogram original signal based on the calibration parameter.

12. A program causing a computer to detect a gaze-path direction of a user, the computer being connected to an electro-oculogram measuring unit that measures an electro-oculogram resulting from an eye movement and outputs an electro-oculogram original signal, said program causing the computer to execute:

presenting a calibration index to the user;

detecting a saccadic movement from the electro-oculogram original signal, and outputting an electro-oculogram change amount, the saccadic movement being a rapid eyeball movement which occurs when a gaze-point of the user moves to the calibration index presented in said presenting a calibration index, and the electro-oculogram change amount being an amount of change in the electro-oculogram before or after the saccadic movement;

calculating a calibration parameter based on a position of the calibration index presented in said presenting a calibration index and the electro-oculogram change amount that has been output in said detecting a saccadic movement; and

detecting the gaze-path direction of the user from the electro-oculogram original signal based on the calibration parameter.

13. An integrated circuit which detects a gaze-path direction of a user and is connected to an electro-oculogram measuring unit that measures an electro-oculogram resulting from an eye movement and outputs an electro-oculogram original signal, said integrated circuit comprising:

a calibration index presenting unit configured to present a calibration index to the user;

a saccade detection unit configured to detect a saccadic movement from the electro-oculogram original signal, and to output an electro-oculogram change amount, the saccadic movement being a rapid eyeball movement which occurs when a gaze-point of the user moves to the calibration index presented by said calibration index presenting unit, and the electro-oculogram change amount being an amount of change in the electro-oculogram before or after the saccadic movement;

a calibration parameter calculating unit configured to calculate a calibration parameter based on a position of the calibration index presented by said calibration index presenting unit and the electro-oculogram change amount that has been output from said saccade detection unit; and

a calibration unit configured to detect the gaze-path direction of the user from the electro-oculogram original signal based on the calibration parameter.