Accession Number : ADD006712

Title :   Low Contrast Measurement Apparatus.

Descriptive Note : Patent,

Corporate Author : DEPARTMENT OF THE AIR FORCE WASHINGTON DC

Personal Author(s) : Benkley ,Fred G ; Sauermann,Gerhard O

Report Date : 02 Oct 1979

Pagination or Media Count : 5

Abstract : A low contrast measurement apparatus for electronically measuring video signal modulation under low contrast scene conditions. The measurement apparatus utilizes a low contrast periodic optical bar chart in conjunction with a filter-integrator processor to measure very low contrast ratios. The filter-integrator processor contains a filter which is tuned to the corresponding fundamental frequency of the bar chart, thereby reducing the noise bandwidth and consequently improving the signal-to-noise ratio. The filtered signal is integrated over one whole picture frame which results in an improved signal to noise ratio. The integrated output of the filtered video signal constitutes a linearly increasing ramp with a period equal to the frame time and whose height is proportional to the amplitude of the periodic signal. (Author)

Descriptors :   *Patents, *Image intensifiers(Electronics), *Video signals, Video amplifiers, Modulation, Television display systems, Electric filters, Bar codes, Signal to noise ratio, Clipper circuits, Contrast, Measuring instruments

Subject Categories : Electrooptical and Optoelectronic Devices
      Radio Communications

Distribution Statement : APPROVED FOR PUBLIC RELEASE