Techniques for locating the stereo axis of stereo-pair images

A pair of stereoscopic images can be created by rotating a solid object through a small angle and capturing two images of that object, one before and one after the rotation. The pair of images is called an approximate stereo-pair, and the projection of the axis of rotation onto the stereo-pair is called the stereo axis. For the stereo-pair to be fusible, or perceived as three-dimensional, the stereo-pair must be rotated so that the stereo axis is perpendicular to the observer´s inter-pupillary axis, the imaginary line connecting the centers of focus of the observer´s eyes. Techniques are presented for locating the stereo axis of a stereo-pair