you are here: IRT home > Glossary

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 color temperatures. An infrared pyrometer measures infrared radiation and relates it to target surface temperature.

Back to Top