Diagram showing the optical path and key components of a stereo plotter. The photographs are mounted in the right and left photograph plates respectively (at the top). Through a system of lenses and prisms the operator will be able to view both photographs simultaneously.
With normal binocular vision a stereoscopic image can be seen. The operator can adjust the viewing point within the photographs by moving the photographic plates mechanically and positions plotted / recorded in all three planes (x, y, z).