Definition

The point of origin or termination of bundles of PERSPEC­TIVE RAYS. The two such points usually associated with a survey photograph are the interior perspective centre and the exterior perspective centre. In a perfect lens-camera system, PERSPECTIVE RAYS from the interior perspective centre to the photographic IMAGES enclose the same angles as the corresponding RAYS from the exterior perspective centre to the objects photographed. In a LENS having DISTORTION this is true only for a particular zone of the PHOTOGRAPH. In a perfectly adjusted lens-camera system the exterior and interior perspective centres correspond, respectively, to the front and rear NODAL POINTS of the camera lens.