Emissivity Thermal Imaging


What is emissivity and why is it important?

Emissivity Thermal Imaging

All objects at temperatures above absolute zero emit thermal radiation. Thermal radiation emitted depends on the emissivity of the object’s surface. Emissivity is defined as the amount of the energy radiated from a material’s surface to that radiated from a blackbody (a perfect emitter). Emissivity is a dimensionless number between 0 (for a perfect reflector) and 1 (for a perfect emitter). The emissivity of a surface depends not only on the material but also on the nature of the surface.

Knowledge of surface is important both for accurate non-contact temperature measurement and for heat transfer calculations. Radiation thermometers detect the thermal radiation emitted by a surface. When viewing ‘real’ more reflective surfaces, with a lower emissivity, less radiation will be received by the thermometer than from a blackbody at the same temperature and so the surface will appear colder than it is unless the thermometer reading is adjusted to take into account the material surface emissivity.

If you would like to discuss Emissivity thermal imaging contact our experts on 020 3044 2940.