Accession Number : ADD003070
Title : Apparatus and Method for the Remote Detection of Vibrations of Diffuse Surfaces.
Descriptive Note : Patent,
Corporate Author : DEPARTMENT OF THE ARMY WASHINGTON D C
Personal Author(s) : Rosati,Vincent J
Report Date : 27 Apr 1976
Pagination or Media Count : 4
Abstract : Apparatus and method for the remote detection of vibrations of diffuse surfaces is described. A beam of coherent light incident on a vibrating diffuse surface is scattered. A photodetector sees the scattering as a time-varying intensity distribution related to the vibration frequency of the surface. The detected time-varying intensity distribution is converted into time-varying electrical currents which can be rendered audible by using a loudspeaker or visual by using an oscilloscope. The invention provides a novel method and apparatus for the covert surveillance of distant conversations, movements of people, movements of vehicles, and the like. This is accomplished by the remote detection of vibrations of a diffuse surface of which some examples are windows, window shades, door panels, walls and trees.
Descriptors : *Remote detectors, *Vibration, *Patents, Covert operations, Optical detectors, Coherent radiation, Laser beams, Photodetectors, Warning systems, Acoustic detectors
Subject Categories : Optical Detection and Detectors
Distribution Statement : APPROVED FOR PUBLIC RELEASE