Apparatus for measuring sighting direction

Claim 1

An apparatus for measuring a sighting direction of an eye ball of an operator, comprising: a camera oriented toward the eye ball of the operator for receiving an image transmitted from the eye ball and providing image data therefrom; a first light source coaxially located with said camera on a coaxial line on which said camera is located, for emitting an invisible light toward the eye ball; a second light source located apart from said first light source at a position (F2) and also emitting invisible light toward the eye ball; first arithmetic operation means for solving, according to images of the eye ball received by said camera, a) a first expression representing a first straight line (F1A) passing between a center (Q) of a pupil of the eye ball and a focus point (F1) of said camera; b) a second expression representing a second straight line (F1B) passing between a position (P') of reflection of light from said first light source and the focus point (F1) of said camera; and c) a third expression representing a third straight line (F1C) passing between a position (P) of reflection of light from said second light source and the focus point (F1) of said camera; second arithmetic operation means for calculating a position of the center (O) of the corneal sphere of the eye ball according to the second and third expressions representing the second and third straight lines passing through the positions of the reflections of light from said first and second light sources calculated by the first arithmetic operation means; and third arithmetic operation means for calculating a sighting direction of the eye ball according to an expression representing a straight line passing through the center (Q) of the pupil, obtained by the first arithmetic operation means, and the center (O) of the corneal sphere of the eye ball, obtained by said second arithmetic operation means.

Claim 2

An apparatus for measuring a sighting direction of an eye ball of an operator, comprising: a camera oriented toward the eye ball of the operator for receiving an image transmitted from the eye ball and providing image data therefrom; a first light source coaxially located with said camera on a coaxial line on which said camera is located, for emitting an invisible light toward the eye ball; a second light source located apart from said first light source at a position (F2) and also emitting invisible light toward the eye ball; first arithmetic operation means for solving, according to images of the eye ball received by said camera, a) a first expression representing a first straight line (F1A) passing between a center (Q) of a pupil of the eye ball and a focus point (F1) of said camera; b) a second expression representing a second straight line (F1B) passing between a position (P') of reflection of light from said first light source and the focus point (F1) of said camera; and c) a third expression representing a third straight line (F1C) passing between a position (P) of reflection of light from said second light source and the focus point (F1) of said camera; second arithmetic operation means for calculating a position of the center (O) of the corneal sphere of the eye ball according to the second and third expressions representing the second and third straight lines passing through the positions of the reflections of light from said first and second light sources calculated by the first arithmetic operation means; and third arithmetic operation means for calculating a sighting direction of the eye ball according to an expression representing a straight line passing through the center (Q) of the pupil, obtained by the first arithmetic operation means, and the center (O) of the corneal sphere of the eye ball, obtained by said second arithmetic operation means.