Infrared (IR) Thermography, thermal imaging cameras, and thermal video, are all types of infrared imaging technology. Thermo-graphic cameras detect radiation in the infrared range of the electromagnetic spectrum (900'14,000 nanometers or 0.9'14 ?m) and from that radiation produce images. According to the black body radiation law, objects above 0 Kelvin radiate infrared radiation.

With thermography it is possible to see one's environment with or without visible illumination. Radiation emitted by an object increases with temperature. So, thermography allows one to see variations in those temperatures. When viewed through a thermographic camera, warm objects will stand out well against cooler backgrounds. Humans as well as animals stand out extremely well against their environment. This is why the basis of thermal imaging originates from security and military applications.

Thermal imaging has many construction related uses including electrical and high voltage maintenance applications and the location of overheating connections and parts, which is a sign of their failure. Where insulation becomes faulty, building envelope technicians can see thermal signatures that indicate heat or cold leaks. Roofing inspections can reveal roof failure areas that need to be replaced, saving tens of thousands of dollars in a complete roof replacement. Facilitation of these types of green energy repairs can lower the strain on any type of HVAC system as well as lower energy cost altogether. Higher thermally sensitive units can also even be used to detect termites, mold, and all sorts of unwanted pests. This makes infrared thermal imaging extremely useful to all forms of extermination companies.

The operation of a thermo-graphic camera is very similar to both a radar gun and a camera. This enables the user to see in the full infrared spectrum. Some models even have the ability to record the output. However, a recording module is not always built-in.

Most modern thermal imaging cameras make use of a CMOS focal plane array (FPA). The newest hand held imagers utilize low-cost and un-cooled microbolometers FPA sensors. With resolution around 160x120 and 320x240 pixels, they are considerably lower than that of optical cameras. Some of the more expensive models can offer up to 640 x 512. Although thermo-graphic imaging cameras are more expensive than their ?light only? counterparts, their cost over recent years has dropped considerably. This has made their use is the building inspection, maintenance, medical , and construction fields much more common place. Older, less rugged models requiring cryogenic cooling are now being replaced by portable, hand held, and cost effective models that are approaching the same thermal sensitivity.