The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 27, 1989
Filed:
Sep. 14, 1978
Gunther Kurbitz, Aalen, DE;
Karl-Heinz D Simon, Oberkochen, DE;
Hans-Richard Weinheimer, Konigsbronn, DE;
Carl-Zeiss-Stiftung, Heidenheim/Brenz, Oberkochen, DE;
Abstract
The presence of an operating helicopter within a given field of view is remotely and passively monitored by optically imaging the field of view at a focal surface, using an infrared detector to produce an electrical signal. The electrical signal is filtered with a narrow pass-band having a center frequency which is adjustable over a range which spans the respective modulation frequencies of characteristic infrared radiation emitted by the rotating blades of each of a plurality of helicopters of different type. Provision is made to indicate such component of the electrical signal as survives the filtering step.