Method and apparatus to measure pupil size and position

Abstract

Embodiments of the present invention are method and apparatus for measuring the size and position of an eye's pupil, and for doing so rapidly. In particular, embodiments of the present invention are methods and apparatus for determining pupil size and position without measuring the fall pupil and for doing so rapidly, in real time, as data are being collected. An embodiment of the present invention is a method for determining a size of an eye's pupil which comprises the steps of: (a) storing reference partial areas for a reference pupil that are associated with scan lines of a two-dimensional image of the eye; (b) analyzing one or more scan lines comprised of pixels from another two-dimensional image of the eye as follows: (c) determining of which the pixels in an analyzed scan line are in the pupil; (d) determining a sum of such pixels for the analyzed scan line; (e) determining a partial area corresponding to the scan line by adding the sum to the partial area for previously analyzed scan lines; and (f) estimating the size of the pupil from the partial areas determined from the another two dimensional image and the partial areas for the reference pupil. Further, the inventive and apparatus utilizes an iterative estimation procedure that may be terminated whenever successive estimates satisfy a predetermined convergence criterion.