# Glossary

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## Glossary of Thermography Terms

### Blackbody, Blackbody Radiator

A blackbody absorbs all incident radiation. From Kirchhoff’s law it follows that a blackbody is also a perfect radiator. A perfect radiator radiates the maximum number of photons in a unit time from a unit area in a specified spectral interval into a hemisphere that any body in thermodynamic equilibrium at the same temperature can radiate. In Thermography, a calibration reference radiator is referred to as a “Blackbody radiator”, although it is a practical, not theoretical device.

### Blackbody Curves

Plots of radiant power spectral exitance vs. wavelength (W/m²/µm) for various temperatures according to the Planck equation. These curves show the maximum amount of energy at any given wavelength that can be radiated by an object due solely to its temperature. Also called Planck curves.

### Bolometer, Infrared (Micro-bolometer)

A type of thermal infrared detector commonly used in spot pyrometers. The micro-bolometer is used in uncooled imaging radiometers;