you are here: IRT home > Glossary

Glossary of Thermography Terms

Objective, Objective Lens

The primary lens of an optical system, On an infrared instrument, usually the interchangeable lens that defines the total field of view.


Impervious to radiant energy. In Thermography, an opaque material is one that does not transmit thermal infrared energy, (τ = 0).

Optical Element, Infrared

Any element that collects, transmits, restricts or reflects infrared energy as part of an infrared sensing or imaging instrument.


Collecting samples at a rate higher than the Nyquist critical frequency, fc = 1/(2∆), where ∆ is the sampling interval. Applies to both time and spatial domains.

Back to Top