Patent ID: 8538044

Claim:
A line-of-sight direction determining apparatus comprising: an imaging section that takes an image of a face including right and left eyes; an illuminating section that illuminates corneas of the right and left eyes using a light source; a pupil detecting section that detects a first coordinate and a second coordinate, the first coordinate and the second coordinate being a center coordinate of the pupil of one of the right and left eyes and a center coordinate of the pupil of the other one of the right and left eyes, respectively; a cornea reflection image detecting section that detects a third coordinate and a fourth coordinate, the third coordinate and the fourth coordinate being a center coordinate of a cornea reflection image of the light source on the cornea of one of the right and left eyes and a center coordinate of a cornea reflection image of the light source on the cornea of the other one of the right and left eyes, respectively; a line-symmetric position calculating section that calculates a perpendicular bisector of a first line segment connecting between the first coordinate and the second coordinate, and calculates a line-symmetric position coordinate being a position coordinate that is line-symmetric to the third coordinate with respect to the perpendicular bisector; and a line-of-sight direction determining section that calculates a coordinate distance between the fourth coordinate and the line-symmetric position coordinate, and, based on a comparison of the coordinate distance and a predetermined threshold, determines a direction of line of sight of the right and left eyes.