Eyeball detection device, eye-gaze tracking device, eyeball detection method, and medium

1. An eyeball detection device comprising:

an imaging device that obtains a face image which includes left and right eyeball images of target person;

a first distance calculating unit that calculates a first-type distance representing distance between the target person and the imaging device; and

an eyeball searching unit that performs a search for the left and right eyeball images from the face image and, when one eyeball image of the left and right eyeball images of the target person is detected, searches for other eyeball image of the target person from the face image based on search result regarding the one eyeball image as obtained by the eyeball detecting unit, based on the first-type distance, and based on a second-type distance representing distance between left and right eyeballs of the target person,

wherein the eyeball searching unit calculates eyeball position based on the one eyeball image of the left and right eyeball images,

predicts eyeball position of the other eyeball image based on eyeball position of the one eyeball image, based on the first-type distance, and based on the second-type distance,

performs the search based on prediction results,

sets, with respect to the one eyeball image, first-type search regions at positions on a vertical straight line that is parallel to a horizontal direction, and performs the search in the first-type search regions, and

when the other eyeball image is not detected in the first-type search regions, sets second-type search regions that are shifted by a predetermined angle with respect to the first-type search regions in a rotation direction around a position of the one image, and performs the search in the second-type search regions.

2. The eyeball detection device according to claim 1 , further comprising a second distance calculating unit that calculates the second-type distance based on the face image obtained by the imaging device.

3. The eyeball detection device according to claim 1 , wherein the first distance calculating unit calculates the first-type distance based on the face image obtained by the imaging device.

4. An eye-gaze tracking device that

detects left and right eyeball images of target person using the eyeball detection device according to claim 1 , and

tracks eye gaze of the target person based on detection result.

5. An eyeball detection method comprising:

obtaining a face image that includes left and right eyeball images of target person;

calculating a first-type distance representing distance between the target person and the imaging device;

performing a search for the left and right eyeball images from the face image; and

searching that, when one eyeball image of the left and right eyeball images of the target person is detected, includes searching for other eyeball image of the target person from the face image based on search result regarding the one eyeball image, based on the first-type distance, and based on a second-type distance representing distance between left and right eyeballs of the target person,

wherein the searching calculates eyeball position based on the one eyeball image of the left and right eyeball images,

predicts eyeball position of the other eyeball image based on eyeball position of the one eyeball image, based on the first-type distance, and based on the second-type distance,

performs the search based on prediction results,

sets, with respect to the one eyeball image, first-type search regions at positions on a vertical straight line that is parallel to a horizontal direction, and performs the search in the first-type search regions, and

when the other eyeball image is not detected in the first-type search regions, sets second-type search regions that are shifted by a predetermined angle with respect to the first-type search regions in a rotation direction around a position of the one image, and performs the search in the second-type search regions.

6. A non-transitory computer readable recording medium storing therein an eyeball detection program that causes a computer to execute:

an operation of obtaining a face image that includes left and right eyeball images of target person;

an operation of calculating a first-type distance representing distance between the target person and the imaging device;

an operation of performing a search for the left and right eyeball images from the face image; and

an operation of searching that, when one eyeball image of the left and right eyeball images of the target person is detected, includes searching for other eyeball image of the target person from the face image based on search result regarding the one eyeball image, based on the first-type distance, and based on a second-type distance representing distance between left and right eyeballs of the target person,

wherein the operation of searching calculates eyeball position based on the one eyeball image of the left and right eyeball images,

predicts eyeball position of the other eyeball image based on eyeball position of the one eyeball image, based on the first-type distance, and based on the second-type distance,

performs the search based on prediction results,

sets, with respect to the one eyeball image, first-type search regions at positions on a vertical straight line that is parallel to a horizontal direction, and performs the search in the first-type search regions, and

when the other eyeball image is not detected in the first-type search regions, sets second-type search regions that are shifted by a predetermined angle with respect to the first-type search regions in a rotation direction around a position of the one image, and performs the search in the second-type search regions.