What is a Thermal Infrared Camera?

Glossary Definition

Thermal cameras use infrared imaging in the MWIR or LWIR wavelengths to “see” heat instead of light. Sometimes referred to as “FLIR” cameras, they create images based on the temperature of an object instead of its visible features.

So how does thermal imaging see heat?

All objects with a temperature above absolute zero (-273°C/-459°F) emit infrared radiation in the mid-wave infrared (MWIR) and long-wave infrared (LWIR) wavelengths (3µm–14µm) in an amount proportional to the temperature of the object. Thermal cameras detect this radiation, then convert the temperature variations into a greyscale image. This image uses brighter and darker shades of grey to represent hotter and cooler temperatures, giving a visual representation of the heat profile in the scene.

Many thermal imagers can also apply color profiles to these images, showing hotter objects as yellow and cooler objects as blue for example. This colorization makes it easier to compare temperatures within the image.

Read more on our Thermal Technology Page.