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公开(公告)号：EP0861426A1
公开(公告)日：1998-09-02
申请号：EP96938333.0
申请日：1996-11-11
CPC分类号： G01J5/06
摘要： An infrared optical system (100) incorporates a lens (118) imaging a remote scene onto a detector (112) within a cold shield (114). Stray radiation incident on the detector (112) is reduced by an optical stop in the form of a light emitting diode (LED) (126) producing negative luminescence. The LED (126) emits less radiation than background, and contributes less to the detector photon noise than an optical stop not exhibiting negative luminescence.
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公开(公告)号：EP0861426B1
公开(公告)日：2001-08-29
申请号：EP96938333.0
申请日：1996-11-11
IPC分类号： G01J5/06
CPC分类号： G01J5/06
摘要： An infrared optical system (100) incorporates a lens (118) imaging a remote scene onto a detector (112) within a cold shield (114). Stray radiation incident on the detector (112) is reduced by an optical stop in the form of a light emitting diode (LED) (126) producing negative luminescence. The LED (126) emits less radiation than background, and contributes less to the detector photon noise than an optical stop not exhibiting negative luminescence.
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公开(公告)号：EP0880853A1
公开(公告)日：1998-12-02
申请号：EP96931886.0
申请日：1996-09-24
CPC分类号： H04N5/33 , G01J5/522 , H04N5/3651
摘要： A thermal imaging system (10) which is accoupled and operates by scanning recreates a thermal image by superimposing measured variations in infrared emission from a scene (22) onto a reference level supplied by a light emitting diode (28). The diode (28) is both a positive and negative luminescent emitter; emitted flux is current controlled to be equivalent to black body radiation at a range of temperatures which may be colder or hotter than ambient. A signal generated when the system (10) switches between scene and diode observation is a measure of the difference between the mean scene temperature and the diode effective temperature. In response to this digital, control means adjust the bias current through the diode (28) in order to reduce the temperature difference. The reference temperature converges towards the mean scene temperature as this process is repeated. Absolute temperature is thus restored and some image defects removed.
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公开(公告)号：EP0842581A1
公开(公告)日：1998-05-20
申请号：EP96925850.0
申请日：1996-07-29
CPC分类号： H04N5/3651 , F41G7/001 , F41G7/2253 , F41G7/2293 , H04N5/33
摘要： A thermal sensing system (10) including an array of photon detectors (14) produces a detector-dependent response to irradiation. Variations in individual detector characteristics produce a fixed pattern noise which degrades an image or other response. A switchable mirror (M1) may at one position (Pcal) direct infrared radiation from a light emitting diode (20) onto the detector array (14). The diode (20) is both a negative and positive luminescent emitter; the flux emitted is current controlled to be equivalent to black body radiation at a range of temperatures both colder and hotter than ambient. Calibration relationships comprising transfer functions relating incident intensity to signal response are derived for each detector. Alternatively the mirror (M1) may be at an observation position (Pobs) and infrared radiation from a remote scene reaches the detector array (14). Resulting detector signals are converted into corrected fluxes using individual calibration relationships previously derived and an image or response with reduced fixed pattern noise is obtained.
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