Inventors:
Wilbur Liebson - Springfield VA
Assignee:
The United States of America as represented by the Secretary of the Army - Washington DC
International Classification:
G01J 100
G02B 2700
Abstract:
A counter-countermeasure provided within a thermal imgaging device (TID) rein an enemy black hole, or cold spot, radiometer (BHR) is prevented from detecting the presence of cryogenic detectors within the TID. The thermal imager counter-countermeasure comprises a beam splitter placed in the primary optical path of the TID and a projection heater positioned to one side of the primary optical path and at, or close to, the same point as the array of cryogenic detectors. In operation, heat radiation from the projection heater, which is referenced to an ambient temperature source in proximity to the TID, is reflected off the beam splitter at the same cross-sectional geometrical area as the cold spot radiation (or absence of heat radiation) from the cryogenic detectors is transmitted through the beam splitter such that when a potential enemy BHR has our TID in its field-of-view (FOV), the cold spot radiation will be masked by heat radiation and thus the cold spot radiation will not be present for detection by the potential enemy BHR. The invention described herein may be manufactured, used, and licensed by the government for governmental purposes without the payment of any royalties thereon.
