Accession Number : ADD007792

Title :   Focus Meter.

Descriptive Note : Patent Application,

Corporate Author : DEPARTMENT OF THE ARMY WASHINGTON DC

Personal Author(s) : Pitruzzello,Michael C

Report Date : 02 Sep 1980

Pagination or Media Count : 15

Abstract : The focus meter is an electronic circuit that is responsive to a video signal input to provide an output signal which indicates the degree of focus on a target. Imaging systems require alignment or focusing of the imaging sensor aimed or directed toward a target. The image sensor is aimed at the target and the degree of focus on the target is varied. As the maximum point of focus is reached a peak signal output results. The input video is coupled to an amplifier. The input signal is then processed through a differentiator to a peak detector. A portion of the signal is coupled from the amplifier to a sync separator circuit which causes a gate signal to be generated to an electronic switch during undesirable portions of the input video signal. This allows the differentiator output to be short-circuited to ground when undesirable signals are present. When the desired video lying between the blanking pulses are present, the differentiated signals are coupled to the detector. The detector measures the peak values. For a typical viewed scene wherein the target being tracked or sensed has reasonable detail, the peak detected value provides an easily measured maximum at the best point of focus. (Author)

Descriptors :   *Patent applications, *Video signals, *Alignment, *Targeting, Spatial filtering, Electrooptics, Forward looking infrared systems, Voltmeters, Dynamic range, Input output processing, Signal processing, Video amplifiers, Peak values, Specifications, Blanking(Electronics), Detectors, Integrated circuits, Schematic diagrams, Waveforms, Television cameras, Focusing, Differentiating circuits

Subject Categories : Electrooptical and Optoelectronic Devices
      Infrared Detection and Detectors

Distribution Statement : APPROVED FOR PUBLIC RELEASE