Abstract: An imaging system incorporating a scanned array of infrared detectors for a presentation of scene data on a display includes gain normalization and averaging circuitry coupled to individual ones of the detectors of the detector array. The gain normalization is accomplished with gain control circuitry structured as a feedback loop introducing equality between the magnitude of an average value of a detector signal and a reference signal. The imaging system comprises a set of channels connecting with respective ones of the detectors, each channel having a gain control circuitry. A common value of the reference signal is applied to each channel. The averaging time is several times greater than the duration of a single scan in the scanning of the detector array so as to introduce gain normalization to subject matter which is substantially uniform throughout a swath of the scene swept by a detector while leaving image points of relatively small objects unaffected by the gain normalization.

Abstract: An imaging system incorporating a scanned array of infrared detectors for a presentation of scene data on a display includes gain normalization circuitry coupled to individual ones of the detectors of the detector array. The normalization circuitry is structured as a feedback loop introducing equality between the magnitude of an average value of a detector signal and a reference signal. The imaging system comprises a set of channels connecting with respective ones of the detectors, each channel having adaptive gain control circuitry. A common value of the reference signal is applied to each channel for uniformity in a displayed image. The averaging time is several times greater than the duration of a single scan in the scanning of the detector array so that the display is relatively free of nonuniformities associated with differing responsivities of the detectors to infrared radiation.

Abstract: An imaging system incorporating a scanned array of infrared detectors for presentation of scene data on a display includes gain normalization circuitry coupled to individual ones of the detectors of the detector array. The normalization circuitry is structured as a feedback loop introducing euality between the magnitude of an average value of a detector signal and a reference signal. The imaging system comprises a set of channels connecting with respective ones of the detectors, each channel having adaptive gain control circuitry. A common value of the reference signal is applied to each channel for uniformity in a displayed image. The averaging time is several times greater than the duration of a single scan in the scanning of the detector array so as the display is relatively free of nonuniformities associated with differing responsivities of the detectors to infrared radiation. A nonlinear gain function is produced by connection of multipliers and/or logarithmic circuitry in a forward branch of the loop.

Abstract: A system is disclosed for frequency compensation and amplitude compression of signals from a scene having targets which radiate infrared energy. The system uses at least two combinations, where each combination consists of an operational amplifier and a variable resistance element. These combinations are electrically coupled to each other. A circuit connected to one of the amplifiers provides high frequency compensation for radiated energy by small targets in the infrared scene. The system also utilizes a reference source which is coupled to the input of another of the amplifiers.