Showing papers by "Spectral Sciences Incorporated published in 1982"

System and method for remote detection and identification of chemical species by laser initiated nonresonant infrared spectroscopy

Abstract: Disclosed is a system and method for remote detection and identification of unknown chemical species in gaseous, aerosol, and liquid states. A pulsed infrared laser is directed at an unknown chemical mass which absorbs energy at the laser wavelength. Due to molecular energy transfer processes, the absorbed laser energy can be re-emitted in one or more wavelength regions nonresonant with the laser wavelength. The re-emitted energy is detected for a period of time which is comparable to or less than the characteristic time for the absorbed radiative energy to be dissipated as heat. The nonresonant infrared emission spectrum of the unknown chemical species is detected with several infrared detectors. The identity of the unknown species, as well as its range and concentration, may be established by comparison of its spectrum to that for known species.

Aircraft Contrast Signatures In The Infrared Spectral Region

Abstract: The methodology for calculating aircraft infrared radiation is developed by expressing the signature in its component parts and then modeling each in terms of a few parameters. The basic signature components are: exhaust plume molecular emissions, airframe thermal emissions, various exposed engine hot parts, and scattered ambient radiation (e.g., earth-shine, sunshine and skyshine). When calculating sensor irradiances for systems studies, the close relationship between the aircraft signature and environmental conditions must be considered. This is illustrated with scene contrast signature calculations for several different observer viewing angles and background types.