Patent US 5,987,151

A visual axis detecting apparatus includes a two-dimensional image sensor having a plurality of detecting lines for receiving light from an eye, a first calculator for (i) detecting a change of luminance for neighboring pixels on the detecting lines, for (ii) calculating a number of pixels whose luminance is changed and a position of a center of gravity of the change of luminance as coordinates of an edge of a pupil of the eye from an amount of the change of luminance, for (iii) obtaining a plurality of coordinates of the edge of the pupil from the plurality of detecting lines, and for (iv) performing a correcting calculation of the plurality of coordinates of the edge of the pupil on the basis of an aspect ratio of a pixel of the image sensor, a second calculator for calculating a position of a center of the pupil from the plurality of coordinates of the edge of the pupil corrected by the first calculator, and a visual axis calculator for calculating a position of a visual axis by using the position of the center of the pupil.