Abstract: A method spectrally and temporally characterizing the fluorescence and/or phosphorescence of a material includes using a frequency-domain cross-correlation fluorometer-phosphorimeter employing an interferometer. A flux-modulated excitation signal is used to excite the material. An interferometer is used to generate an optical path difference (OPD) between portions of an emission signal produced by the excited material to obtain an optical interference signal. The optical interference signal is detected by a heterodyning detection system to determine phase shift and demodulation of the emission signal relative to the excitation signal. Phase shift and demodulation data are acquired at a series of OPD values generated by the interferometer and at a plurality of light source flux-modulation frequencies at each OPD to spectrally and temporally resolve the emission signal.

Abstract: A method spectrally and temporally characterizing the fluorescence and/or phosphorescence of a material includes using a frequency-domain cross-correlation fluorometer-phosphorimeter employing an interferometer. A flux-modulated excitation signal is used to excite the material. An interferometer is used to generate an optical path difference (OPD) between portions of an emission signal produced by the excited material to obtain an optical interference signal. The optical interference signal is detected by a heterodyning detection system to determine phase shift and demodulation of the emission signal relative to the excitation signal. Phase shift and demodulation data are acquired at a series of OPD values generated by the interferometer and at a plurality of light source flux-modulation frequencies at each OPD to spectrally and temporally resolve the emission signal.

Abstract: Spectral imaging apparatus and methods are disclosed. In one embodiment, a spectral imaging apparatus includes a spectral imaging apparatus includes a diffraction grating having one or more entrance apertures formed therein, a collecting reflecting element for reflecting said incident radiation to a diffractive surface of said diffraction grating, and a reimaging system adapted to provide a spectral image at a focal surface. The collecting reflecting element may include an aspherically-shaped portion, and the entrance apertures may be distributed along a straight or a non-straight axis. Alternately, optical fibers may be disposed in the entrance apertures. The spectral image provides a spectrum of radiation such that a first portion of the spectrum of radiation from a first region can be distinguished from a second portion of the spectrum of radiation from a second region.

Abstract: Spectral imaging apparatus and methods are disclosed. In one embodiment, a spectral imaging apparatus includes a spectral imaging apparatus includes a diffraction grating having one or more entrance apertures formed therein, a collecting reflecting element for reflecting said incident radiation to a diffractive surface of said diffraction grating, and a reimaging system adapted to provide a spectral image at a focal surface. The collecting reflecting element may include an aspherically-shaped portion, and the entrance apertures may be distributed along a straight or a non-straight axis. Alternately, optical fibres may be disposed in the entrance apertures. The spectral image provides a spectrum of radiation such that a first portion of the spectrum of radiation from a first region can be distinguished from a second portion of the spectrum of radiation from a second region.

Abstract: The hyperspectral imager includes a diffraction grating, a collecting reflecting element and a reimaging system. The diffraction grating has an entrance slit formed at an entrance slit location therein. The entrance slit has a long dimension oriented in a y-direction. The entrance slit transmits the radiation from a slice of an incoming scene image. The collecting reflecting element receives the transmitted radiation of the incoming scene image and reflects the transmitted radiation to a diffractive surface of the diffraction grating. Grooves on the diffractive surface are substantially parallel to the y-direction. The reimaging system receives radiation diffracted by the diffractive surface. The reimaging system produces a spectral image of the entrance slit at a focal surface. The spectral image provides a spectrum of radiation propagating through the entrance slit into the hyperspectral imager such that the spectrum of radiation from a first region in the y-direction.

Abstract: The hyperspectral imager includes a diffraction grating, a collecting reflecting element and a reimaging system. The diffraction grating has an entrance slit formed at an entrance slit location therein. The entrance slit has a long dimension oriented in a y-direction. The entrance slit transmits the radiation from a slice of an incoming scene image. The collecting reflecting element receives the transmitted radiation of the incoming scene image and reflects the transmitted radiation to a diffractive surface of the diffraction grating. Grooves on the diffractive surface are substantially parallel to the y-direction. The reimaging system receives radiation diffracted by the diffractive surface. The reimaging system produces a spectral image of the entrance slit at a focal surface.

Abstract: A detector array that eliminates the channel spectrum effect. In one embodiment the detector consists of a charge couple device (CCD) detector having a photoactive layer supported on a wedge-shaped substrate. Incident radiation impinging any of the pixels and passing through the substrate to the wedge-shaped surface thereof is reflected back at an angle away from the pixel from which it passed through. An infrared array and a single element detector each including a wedge-shaped substrate are also disclosed. The detectors do not require costly signal processing equipment and further can be constructed in accordance with well known manufacturing techniques and with little or no additional cost beyond that normally associated with producing such devices.

Abstract: A detector array that eliminates the channel spectrum effect. In one embodiment the detector consists of a charge couple device (CCD) detector having a photoactive layer supported on a wedge-shaped substrate. Incident radiation impinging any of the pixels and passing through the substrate to the wedge-shaped surface thereof is reflected back at an angle away from the pixel from which it passed through. An infrared array and a single element detector each including a wedge-shaped substrate are also disclosed. The detectors do not require costly signal processing equipment and further can be constructed in accordance with well known manufacturing techniques and with little or no additional cost beyond that normally associated with producing such devices.

Abstract: An imaging apparatus for aiding landing of aircraft in weather conditions obscuring a pilot's view of a runway. The apparatus comprises a plurality of LED assemblies which are disposed along the runway. Each LED assembly includes a plurality of LEDs, a receiver and a plurality of drivers responsive to the receiver for energizing the LEDs. The LEDs of each LED assembly are pulsed on by signals from a transmitter disposed adjacent an end of the runway. The transmitter also sends synchronization signals to a receiver located on board the approaching aircraft. The receiver on the aircraft is coupled to a processor which uses the synchronization signals to determine when the LEDs are energized and when they are not energized. The processor controls a CCD camera mounted on the aircraft so as to obtain an unobstructed view of the approaching runway. The processor controls the CCD camera such that the camera takes images (i.e., frames) while the LEDs are pulsed on and also while the LEDs are off.

Abstract: An absolute pressure regulator valve assembly for controlling the absolute pressure (P.sub.C) of a fluid source. The absolute pressure regulator valve assembly includes a hollow housing having an inlet port and a discharge port. The inlet port is in fluid communication with the fluid source. The discharge port is associated with a valve seat. A bellows assembly is positioned within the housing. The bellows assembly has an open first end and a closed second end. The first end is gas-tight sealed to the housing and is in fluid communication with a means for providing a reference pressure (P.sub.R) within the bellows assembly. A valve closure element is attached to the closed end of the bellows assembly. The valve closure element is positioned relative to the valve seat wherein motion of the bellows assembly provides opening and closure of the discharge port.

Abstract: Disclosed is an apparatus and method for the measurement of weak signals in an output device, including weak signals in the presence of obscuring noise, by pseudorandom sampling of a repetitive alternating potential waveform and digitally extracting the fundamental hormonic to reconstruct an accurate transfer function for the device being measured.