Abstract: A circuit includes an input capacitor that stores charge based on a current received from a photodetector during a bias phase of the photodetector. The stored charge on the input capacitor is sampled during the sampling phase to determine an amount of light captured by the photodetector. A bias controller supplies a pulsed-bias voltage to the photodetector to generate the current from the photodetector. The bias controller controls the current to a current level below a predetermined current threshold via the pulsed-bias voltage before biasing of the detector and subsequent sampling of the stored charge on the input capacitor is initiated to mitigate 1/F noise in the photodetector.

Abstract: A circuit includes an input capacitor that stores charge based on a current received from a photodetector during a bias phase of the photodetector. The stored charge on the input capacitor is sampled during the sampling phase to determine an amount of light captured by the photodetector. A bias controller supplies a pulsed-bias voltage to the photodetector to generate the current from the photodetector. The bias controller controls the current to a current level below a predetermined current threshold via the pulsed-bias voltage before biasing of the detector and subsequent sampling of the stored charge on the input capacitor is initiated to mitigate 1/F noise in the photodetector.

Abstract: A circuit includes an input capacitor that stores charge based on a current received from a photodetector during a bias phase of the photodetector. The stored charge on the input capacitor is sampled during the sampling phase to determine an amount of light captured by the photodetector. A bias controller supplies a pulsed-bias voltage to the photodetector to generate the current from the photodetector. The bias controller controls the current to a current level below a predetermined current threshold via the pulsed-bias voltage before biasing of the detector and subsequent sampling of the stored charge on the input capacitor is initiated to mitigate 1/F noise in the photodetector.

Abstract: A circuit includes an input capacitor that stores charge based on a current received from a photodetector during a bias phase of the photodetector. The stored charge on the input capacitor is sampled during the sampling phase to determine an amount of light captured by the photodetector. A bias controller supplies a pulsed-bias voltage to the photodetector to generate the current from the photodetector. The bias controller controls the current to a current level below a predetermined current threshold via the pulsed-bias voltage before biasing of the detector and subsequent sampling of the stored charge on the input capacitor is initiated to mitigate 1/F noise in the photodetector.

Abstract: Systems and methods are provided for determining an ensquared energy associated with an imaging system. In one embodiment of the invention, a focal plane array captures an image of a target comprising a plurality of point sources, each point source being associated with a pixel within the focal plane array. An image analysis component estimates an ensquared energy value for the imaging system from respective intensity values of the associated pixels and known relative positions of the plurality of point sources.

Abstract: A multi-band focal plane array architecture operative to detect multiple spectral image. The multi-band focal plane array architecture has an integrated readout circuit, a plurality of first detectors integrated in the readout circuit and a plurality of second detectors deposited on the readout circuit. Preferably, the first detectors are operative to detect visible signals and the second detectors are operative to detect infrared signals. The first and second detectors are arranged in a checkerboard pattern, in alternate rows or columns, or at least partially overlapped with each other to realize simultaneous detection in two different wavelength bands. The architecture may also have an additional integrated readout circuit flip-chip bonded to the integrated readout circuit. By forming a plurality of third detectors on the additional integrated readout circuit, a tri-band focal plane array may be realized.

Abstract: A multi-band focal plane array architecture operative to detect multiple spectral image. The multi-band focal plane array architecture has an integrated readout circuit, a plurality of first detectors integrated in the readout circuit and a plurality of second detectors deposited on the readout circuit. Preferably, the first detectors are operative to detect visible signals and the second detectors are operative to detect infrared signals. The first and second detectors are arranged in a checkerboard pattern, in alternate rows or columns, or at least partially overlapped with each other to realize simultaneous detection in two different wavelength bands. The architecture may also have an additional integrated readout circuit flip-chip bonded to the integrated readout circuit. By forming a plurality of third detectors on the additional integrated readout circuit, a tri-band focal plane array may be realized.

Abstract: A method of aligning a lens assembly to a focal plane array is provided. The method may comprise the steps of providing an upper cold shield which holds the lens assembly, providing a lower cold shield for holding the focal plane array, mounting the upper cold shield onto the lower cold shield, lowering the temperature of the upper and lower cold shield to a cryogenic level, translating the upper cold shield with respect to the lower cold shield until the lens assembly is aligned to the focal plane array while the upper and lower cold shields are at the cryogenic temperature levels, and fixing the upper cold shield to the lower cold shield while the upper and lower cold shields are maintained at cryogenic levels.

Abstract: Systems and methods are provided for determining an ensquared energy associated with an imaging system. In one embodiment of the invention, a focal plane array captures an image of a target comprising a plurality of point sources, each point source being associated with a pixel within the focal plane array. An image analysis component estimates an ensquared energy value for the imaging system from respective intensity values of the associated pixels and known relative positions of the plurality of point sources.

Abstract: A direct-view focal plane array (FPA) having a detector layer, an amplification layer, a non-uniformity correction layer and a display layer. A direct path from the detector to the display element in each pixel may be established via a configurable digitally set analog circuit that controls gain and level for non-uniformity correction. The detector layer is operative to detect an infrared image with a raw image pixel response x and convert the infrared image into an electrical signal. The electrical signal is then fed into the amplification layer for amplification and the non-uniformity layer for offset and gain correction. An offset correction coefficient b and a gain correction coefficient m are inputted to the non-uniformity layer, to transform the raw image pixel response x into a corrected pixel response y, which prevents the true scene content from bein masked by the fixed pattern.

Abstract: A cold shield of a cryogenic camera. The cold shield reflects external thermal radiation away from the cryogenic camera, so as to shield the cryogenic camera in a cryogenic temperature such that no internal thermal radiation will be generated. The cryogenic camera has a lens assembly and a focal plane array. The cold shield has an upper cold shield member for holding the lens assembly and a lower cold shield member for holding the focal plane array. The upper cold shield member fits over the lower cold shield member by contact friction, such that limited translation and rotation of the lower cold shield member relative to the upper cold shield member are allowable. Therefore, the cold shield allows a fine adjustment for aligning the lens assembly to the focal plane array.

Abstract: A photoconductive bolometer infrared detector using a detector material that has a resistance changed due to photo-excitation and thermal-excitation from an incident radiation in the infrared range. The resistance changes caused by photo-excitation and the thermal excitation are additive for this detector material. The detector material is suspended over a substrate by a gap of one quarter wavelength of the incident radiation, such that the thermal absorption of the incident radiation can be enhanced. Preferably, the detector material is lead selenide that has a thermal coefficient of resistance as high as 3.45%° C.?1, which is about 60% higher than that of vanadium oxide that has been widely used as the detector material in the conventional microbolometers. This detector structure allows dual band uncooled or moderately cooled operation.

Abstract: An imaging device is provided which may include a plurality of imaging lenses. Each imaging lens may be placed adjacent to a dispersive element. The imaging lenses and dispersive element(s) may be placed adjacent to a focal plane array to allow light from a light emitting event traveling through the imaging lenses to be simultaneously received by the focal plane array. One of the optical channels provides continuous broadband imagery without interfering with the operation of the dispersive optical channels. No moving parts are required in this small compact system, and no reconfiguration during operation is necessary to enable any of the functions, they are all simultaneous. Information related to the light received by the focal plane array may be transmitted to a processor for processing to determine whether the light emitting event is of interest and to determine an event type. Broadband imagery provided may be used for situational awareness, targeting, and surveillance.

Abstract: An imaging device is provided which may include a plurality of imaging lenses. Each imaging lens may be placed adjacent to a dispersive element. The imaging lenses and dispersive element(s) may be placed adjacent to a focal plane array to allow light from a light emitting event traveling through the imaging lenses to be simultaneously received by the focal plane array. One of the optical channels provides continuous broadband imagery without interfering with the operation of the dispersive optical channels. No moving parts are required in this small compact system, and no reconfiguration during operation is necessary to enable any of the functions, they are all simultaneous. Information related to the light received by the focal plane array may be transmitted to a processor for processing to determine whether the light emitting event is of interest and to determine an event type. Broadband imagery provided may be used for situational awareness, targeting, and surveillance.

Abstract: A photoconductive bolometer infrared detector using a detector material that has a resistance changed due to photo-excitation and thermal-excitation from an incident radiation in the infrared range. The resistance changes caused by photo-excitation and the thermal excitation are additive for this detector material. The detector material is suspended over a substrate by a gap of one quarter wavelength of the incident radiation, such that the thermal absorption of the incident radiation can be enhanced. Preferably, the detector material is lead selenide that has a thermal coefficient of resistance as high as 3.45%° C.?1, which is about 60% higher than that of vanadium oxide that has been widely used as the detector material in the conventional microbolometers. This detector structure allows dual band uncooled or moderately cooled operation.

Abstract: A method of aligning a lens assembly to a focal plane array is provided. The method may comprise the steps of providing an upper cold shield which holds the lens assembly, providing a lower cold shield for holding the focal plane array, mounting the upper cold shield onto the lower cold shield, lowering the temperature of the upper and lower cold shield to a cryogenic level, translating the upper cold shield with respect to the lower cold shield until the lens assembly is aligned to the focal plane array while the upper and lower cold shields are at the cryogenic temperature levels, and fixing the upper cold shield to the lower cold shield while the upper and lower cold shields are maintained at cryogenic levels.

Abstract: A cold shield of a cryogenic camera. The cold shield reflects external thermal radiation away from the cryogenic camera, so as to shield the cryogenic camera in a cryogenic temperature such that no internal thermal radiation will be generated. The cryogenic camera has a lens assembly and a focal plane array. The cold shield has an upper cold shield member for holding the lens assembly and a lower cold shield member for holding the focal plane array. The upper cold shield member fits over the lower cold shield member by contact friction, such that limited translation and rotation of the lower cold shield member relative to the upper cold shield member are allowable. Therefore, the cold shield allows a fine adjustment for aligning the lens assembly to the focal plane array.

Abstract: An alignment structure and an alignment method which generates a plurality of spot images from the same light source and aligns individual spot images between different fields in independently steps without affecting the alignment of other spot images. The camera has a plurality of focusing members referenced to a common focal plane array of a plurality of detectors. The alignment structure has a light source, a collimator and a multiple-beam generator. A light beam generated by the camera is collimated and split into a plurality of components converging on the camera at angles within field of view of the camera. Multiple fields of a plurality of spot images are formed on the focal plane. By translating and rotating the focusing members, distances of the corresponding spot images between different fields are minimized to align the camera.