Control of Light Intensity in Television Projectors

RCA's television projectors used with vidicon film cameras are equipped with a light-intensity control unit developed for this purpose. The unit is used to control the video output level of the camera by varying the intensity of the projector light source to compensate for varying film density. The angular position of a continuously variable neutral-density filter wedge placed in the condenserlens system of a projector is remotely controlled by a servomechanism. Thus the signal-to-noise ratio of the system is maintained at its optimum value since the camera is operating with essentially constant input level.

Print ISSN

0898-0438

Published

1955-08

Content type

Original Research

DOI

10.5594/J11309