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Glossary of Thermography Terms

Peak – Hold

A feature of an instrument whereby an output signal is maintained at the peak instantaneous measurements for a specified duration.

Photo – Detector (Photon Detector)

A type of infrared detector that has fast response, (on the order of microseconds), limited spectral response and usually requires cooled operation; photo–detectors are used in infrared radiation thermometers, scanners and imagers.


Abbreviation for picture elements. In infrared technology a pixel is a focal plane array element, for scanning systems it is defined by the SRF function or rather associated with a sample, for spot radiometers by FOV.

Planck, Max Karl Ernest Ludwig

German physicist who incorporated quantum physics into the blackbody spectral radiance equation, giving rise to blackbody curves.

Pyroelectric Detector

A type of thermal infrared detector that acts as a current source with its output proportional to the rate of change of its temperature.

Pyroelectric Vidicon (PEV), also called Pyrovidicon

A video camera tube with its receiving element fabricated of Pyroelectric material and sensitive to wavelengths from about 2 to 20 μm; used in infrared thermal viewers.


Any instrument used for temperature measurement. A radiation or brightness pyrometer measures visible energy and relates it to brightness or colour temperatures. An infrared pyrometer measures infrared radiation and relates it to target surface temperature.

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