Accession Number : ADD014515

Title :   Optical Motion Detector Detecting Visible and Near Infrared Light.

Descriptive Note : Patent, Filed 31 May 89, patented 20 Feb 90,

Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON DC

Personal Author(s) : Everett, Hobart R , Jr

Report Date : 20 Feb 1990

Pagination or Media Count : 10

Abstract : An optical motion detector detects changes in scene lighting indicative of motion and is also capable of detecting surveillance by active night vision devices using near-infrared light. The detector includes two photodetectors which each provide data to a signal processing network. One photodetector is sensitive to visible light; the other to near-infrared light. Both signal processing networks are identical and include a sample-and-hold, a comparator network, and a pulse stretcher. The output of a photodetector is provided to the sample-and-hold and comparator network. The comparator network compares a voltage corresponding to the instantaneously detected ambient lighting scene with a voltage corresponding to a reference lighting scene. The pulse stretcher receives the output of the comparator network and in turn provides an output to a logical processor. The logical processor compares the outputs of both signal processing networks and provides an output indicating surveillance with near-infrared light. The logical processor also indicates any perturbations in intensities of incandescent and fluorescent light. Patents. (edc)

Descriptors :   *INFRARED DETECTORS, *OPTICAL DETECTORS, *PATENTS, *PHOTODETECTORS, *SIGNAL PROCESSING, CHANGE DETECTION, COMPARATORS, FLUORESCENCE, ILLUMINATION, INDICATORS, INFRARED RADIATION, INFRARED SURVEILLANCE, INTENSITY, LIGHT, MOTION, NEAR INFRARED RADIATION, NETWORKS, NIGHT VISION DEVICES, OUTPUT, PERTURBATIONS, PULSE SPACING MODULATION, SENSITIVITY, SURVEILLANCE, VISIBLE SPECTRA

Subject Categories : Optical Detection and Detectors
      Infrared Detection and Detectors

Distribution Statement : APPROVED FOR PUBLIC RELEASE