Abstract

A method of photogrammetry to determine the position of an object in three dimensions using an apparatus for creating a pair of images, and adjusting the overlap of the images by automatically adjusting the convergence of a pair of image gathering means. An adaptor having a set of mirrors is located in front of a camera lens. The outer two mirrors face generally outward along the optical axis of the lens. The centers of the outer two mirrors are spaced apart by an appropriate interocular distance. The convergence of the two outer mirrors is adjustable by swiveling them simultaneously and equally about their centerlines with a ganging mechanism. The apparatus is calibrated by creating a plurality of calibration maps for different distances from the apparatus, each map being related to a given angle of convergence of the mirrors. Then, the apparatus is aimed at a subject, converging the mirrors for maximum overlap. The position of the subject in two dimensions is measured in each of the pair of images, and a calibration map is selected based on the convergence of the mirrors. The two-dimensional position and the selected calibration map is then used to determine the position of the subject in three dimensions.