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Glossary of Thermography Terms

Image, Infrared

See Thermogram.

Imager, Infrared

An infrared instrument that collects the infrared radiant energy from a target surface and produces an (electronic) image of target exitance. This image can be shown on a screen in monochrome (black and white) or color, where the gray shades or color hues correspond respectively to target exitance. Usually does not have any measurement capability.

Image Processing, Thermal

Analysis of thermal images, usually by computer; enhancing the image to prepare it for computer or visual analysis. In the case of an infrared image or thermogram, this could include temperature scaling, spot temperature measurements, thermal profiles, image manipulation, subtraction and storage.

Imaging Radiometer

An infrared thermal imager that provides quantitative thermal images.

Indium Antimonide (InSb)

A material from which fast, sensitive photo- detectors used in infrared scanners and imagers are made. Such detectors require cooling while in operation.


(IR) The infrared spectrum is loosely defined as that portion of the electromagnetic continuum extending from the red visible (0.75µm) to about 1,000µm.

Infrared Radiation Thermometer

An instrument that converts incoming infrared radiant energy from a spot on a target surface to a measurement value that can be related to the temperature of that spot.

Infrared Thermal Imager

See Imager, infrared

Instantaneous Field of View (IFOV)

The angular subtense found by the ratio of the detector dimension divided by the instrument focal length; the projection of the detector at the target plane. In a radiation thermometer this defines the target spot size; in a line scanner or imager it represents one resolution element in a scan line or a thermogram and is one measure of spatial resolution. Also see SRF.


A pattern superimposed on a thermogram or on a line scan that includes or highlights all points that have the same apparent temperature or exitant radiation.

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