Abstract: A method of free space optical communication includes receiving a pulsed optical signal through free space, wherein the pulsed optical signal is received by a receiver device from a laser source device. The method includes decoding the pulsed optical signal in the receiver device, wherein decoding is performed asynchronously with respect to the laser source device. Receiving can include receiving the pulsed optical signal from a reflection of the laser source device when direct line of sight between the receiver device and the laser source device is unavailable. Decoding the pulsed optical signal can include decoding a communication that includes at least one of text, voice, or data.

Abstract: A method of normalizing FPA system gain for varying temperature includes determining an FPA temperature and calculating an FPA system gain as a function of the FPA temperature, system gain for the FPA at a reference temperature, and empirically derived coefficients. The method also includes applying the FPA system gain at the FPA temperature to condition output of the FPA to produce temperature independent image data. An imaging system includes a focal plane array (FPA). A temperature sensor is operatively connected to measure temperature of the FPA. A module is operatively connected to the FPA and temperature sensor to calculate FPA system gain for the FPA as described above, and to apply the FPA system gain to condition output of the FPA to produce temperature independent image data. There need be no temperature control device, such as a thermoelectric cooling device, connected for temperature control of the FPA.

Abstract: A method of enhancing an image includes constructing an input histogram corresponding to an input image received at a focal plane array, the input histogram representing a pixel intensity distribution corresponding to the input image and performing an analytical operation on the input histogram to produce a modified cumulative distribution, wherein the analytical operation is a function of camera temperature. The input image is transformed using the modified cumulative distribution to produce an enhanced output image corresponding to the input image, wherein at least a portion of the input image is enhanced in the output image. In addition to or in lieu of the non-linear operation, the binning edges of the input histogram can be adjusted based on at least one of camera temperature and sensitivity state to construct an adjusted cumulative distribution.

Abstract: A method of normalizing FPA system gain and correcting pixel non-uniformity for varying temperature includes determining an FPA temperature, calculating an FPA system gain as a function of the FPA temperature, and applying the FPA system gain at the FPA temperature to condition output of the FPA to produce temperature independent image data. The method also includes calculating a non-uniformity correction map on a pixel by pixel basis for the FPA, wherein non-uniformity correction for each pixel is a function of the FPA temperature, and applying the non-uniformity correction map to the imaging data from the FPA to produce temperature dependent non-uniformity corrected image data. An imaging system includes a focal plane array (FPA), a temperature sensor operatively connected to measure temperature of the FPA, and a module configured for system gain correction and non-uniformity correction as described above.

Abstract: A method of correcting pixel non-uniformity for varying temperature includes determining an FPA temperature and calculating a non-uniformity correction map on a pixel by pixel basis for the FPA, wherein the non-uniformity correction for each pixel is a function of the FPA temperature and empirically derived coefficients. The method also includes applying the non-uniformity correction map at the FPA temperature to condition output of the FPA to produce temperature dependent non-uniformity corrected image data. An imaging system includes a focal plane array (FPA). A temperature sensor is operatively connected to measure FPA temperature. A module is operatively connected to the FPA and temperature sensor to calculate and apply a non-uniformity correction map as described above. There need be no temperature control device for the FPA. The FPA can include a buffered current mirror pixel architecture, and can include an InGaAs material for infrared imaging.

Abstract: An imaging method includes receiving electromagnetic radiation at a focal plane array of a handheld device. The electromagnetic radiation is processed within the handheld device, and visible images are displayed on the handheld device. The displayed visible images are indicative of a scene, and include a designator and a designator identifier when a high frequency laser pulse is in the scene. The designator and designator identifier represent the high frequency pulsed electromagnetic radiation received by the focal plane array when a high frequency pulse is present in the scene.

Abstract: A method of enhancing an image includes constructing an input histogram corresponding to an input image received at a focal plane array, the input histogram representing a pixel intensity distribution corresponding to the input image and performing an analytical operation on the input histogram to produce a modified cumulative distribution, wherein the analytical operation is a function of camera temperature. The input image is transformed using the modified cumulative distribution to produce an enhanced output image corresponding to the input image, wherein at least a portion of the input image is enhanced in the output image. In addition to or in lieu of the non-linear operation, the binning edges of the input histogram can be adjusted based on at least one of camera temperature and sensitivity state to construct an adjusted cumulative distribution.

Abstract: A method of controlling FPA system stabilization includes calculating FPA adjustments as a function of FPA temperature and adjusting a TEC set point to assist the FPA adjustments in attaining a predetermined level of FPA performance. Adjusting the TEC set point can include adjusting the TEC set point as a function of at least one of ambient temperature, FPA temperature, or disparity between the predetermined level of FPA performance and a level of FPA performance obtainable by calculating the FPA adjustments as a function of FPA temperature alone without adjusting the TEC set point.

Abstract: A method of identifying at least one target includes receiving a series of images over time of pulsed energy reflected from the at least one target, each image including a plurality of pulses related to different first and second pulse codes, detecting the pulses in an image of the received images, and outputting pulse detection information including XY coordinates and arrival time information associated with the respective detected pulses. The method further includes associating the pulse detection information with the first and second pulse codes based on the arrival time information, and generating output position information for the at least one target in space that indicates output positions for the at least one target based on the XY coordinates and being associated with the corresponding first and second pulse codes.

Abstract: A method of normalizing FPA system gain and correcting pixel non-uniformity for varying temperature includes determining an FPA temperature, calculating an FPA system gain as a function of the FPA temperature, and applying the FPA system gain at the FPA temperature to condition output of the FPA to produce temperature independent image data. The method also includes calculating a non-uniformity correction map on a pixel by pixel basis for the FPA, wherein non-uniformity correction for each pixel is a function of the FPA temperature, and applying the non-uniformity correction map to the imaging data from the FPA to produce temperature dependent non-uniformity corrected image data. An imaging system includes a focal plane array (FPA), a temperature sensor operatively connected to measure temperature of the FPA, and a module configured for system gain correction and non-uniformity correction as described above.

Abstract: A method of correcting pixel non-uniformity for varying temperature includes determining an FPA temperature and calculating a non-uniformity correction map on a pixel by pixel basis for the FPA, wherein the non-uniformity correction for each pixel is a function of the FPA temperature and empirically derived coefficients. The method also includes applying the non-uniformity correction map at the FPA temperature to condition output of the FPA to produce temperature dependent non-uniformity corrected image data. An imaging system includes a focal plane array (FPA). A temperature sensor is operatively connected to measure FPA temperature. A module is operatively connected to the FPA and temperature sensor to calculate and apply a non-uniformity correction map as described above. There need be no temperature control device for the FPA. The FPA can include a buffered current mirror pixel architecture, and can include an InGaAs material for infrared imaging.

Abstract: A method of normalizing FPA system gain for varying temperature includes determining an FPA temperature and calculating an FPA system gain as a function of the FPA temperature, system gain for the FPA at a reference temperature, and empirically derived coefficients. The method also includes applying the FPA system gain at the FPA temperature to condition output of the FPA to produce temperature independent image data. An imaging system includes a focal plane array (FPA). A temperature sensor is operatively connected to measure temperature of the FPA. A module is operatively connected to the FPA and temperature sensor to calculate FPA system gain for the FPA as described above, and to apply the FPA system gain to condition output of the FPA to produce temperature independent image data. There need be no temperature control device, such as a thermoelectric cooling device, connected for temperature control of the FPA.

Abstract: A laser designator pulse detector includes an InGaAs photodetector configured to convert laser signals into electrical signals. A Read Out Integrated Circuit (ROIC) is operatively connected to the InGaAs photodetector to condition electrical signals from the InGaAs photodetector. The ROIC can be operatively connected to a peripheral device including one or more modules configured to process signals from the ROIC and provide pulse detection, decoding, and tracking. In another aspect, a laser designator pulse detector includes a two-dimensional array of photodetectors configured to convert laser signals into electrical signals. A ROTC as described above is operatively connected to the two-dimensional array of photodetectors.

Abstract: A pulse repetition frequency detector, tracker, and decoder includes a two-dimensional InGaAs FPA of photodetectors configured to convert laser signals into electrical signals. A ROIC is operatively connected to the InGaAs FPA to condition electrical signals from the InGaAs FPA. A module is operatively connected to the ROIC to decode pulsed codes in the conditioned electrical signals and to provide output for tracking decoded laser spots in two-dimensional space. In another aspect, an imaging device includes an imager with an imaging FPA operatively connected to a first ROIC for imaging. A pulse repetition frequency detector, tracker, and decoder including a second ROIC as described above, is operatively connected to the first ROIC. The first and second ROICs are operatively connected to correlate the position of decoded laser spots in images from the imaging FPA.