Fundamentals of radiation thermometry

2020-12-16 09:53


Fundamentals of radiation thermometry

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History of Radiation Thermometry

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Planck's Law of Radiation

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Blackbody radiation and emissivity

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Transmission / Absorption of the atmosphere and media

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Components of a radiation thermometer

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Influences on measurement with a radition thermometer

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Effectof changing ambient temperature l=8…14 mm, e = 0.98 compared to e =1

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Sizeof Source Effect

= Sources of equal temperature butdifferent size give rise to different apparent temperatures

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Calibration sources

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Different calibration schemes

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Typical Calibration steps

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Calibrationof thermal imagers

  • Similar to radiation thermometers

  • Calibration of a specified region of theimage using variable temperature blackbody sources

  • Evaluation of the size-of-source effect(SSE)

  • Check effect of alignment/ calibrationdistance

  • Evaluation of the short term stability byperforming repeat measurements


Evaluation of image non-uniformity (if possible) Consider distance effect if the imager is to be used at different distance compared to calibration Field of view can be larger (large aperture source necessary, e.g. flat plate radiator) Some of the uncertainties (e.g.SSE) can be larger than for radiation thermometers


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