Universal Photogrammetric Electronic Rectifier.

An electronic line scanning machine is described which will line scan an oblique aerial photograph and produce a rectified print automatically. The machine incorporates optical-mechanical scanning and reproduces by means of an ultrasonic light modulator. The rectifier will handle camera formats up to 9 x 18, focal lengths from 3 to 100 and tilt angles up to 80. Scanning is done at 500 lines per minute. The basic theory of line scanning for aerial image rectification is discussed and the development of the equations for the computer required for the machine is given.