Accession Number : ADD002163

Title :   System for Electronic Adjustment of Effective Contrast Ratio in Photographic Reproduction.

Descriptive Note : Patent,

Corporate Author : DEPARTMENT OF THE AIR FORCE WASHINGTON D C

Personal Author(s) : Kaufman,Irving

Report Date : 16 Dec 1975

Pagination or Media Count : 7

Abstract : The patent describes a system for controlling the contrast of light intensities falling upon a photosensitive surface after being transmitted through a transparency. Polarized light passes the transparency to a partially silvered mirror which reflects a portion of the light to an array of photosensors and also transmits a portion of the light to a ferroelectric plate. The photosensitive array and the ferroelectric plate are simultaneously scanned. At each scanning position of the photosensitive surface an electrical signal is caused to be applied to the corresponding scanned position of the ferroelectric plate, the intensity being controlled by a variable amplifier. The controlled light passing from the ferroelectric plate is transmitted through a polarizer to the photosensitive surface.

Descriptors :   *Photodetectors, *Photographic lighting systems, *Patents, Arrays, Ferroelectric materials, Lead compounds, Lanthanum compounds, Zirconates, Titanates, Optical scanning

Subject Categories : Electrical and Electronic Equipment
      Photography
      Optics

Distribution Statement : APPROVED FOR PUBLIC RELEASE