An infrared camera is a non-contact device that detects infrared energy (heat) and converts it into an electronic signal, which is then processed to produce cameraa thermal image on a video monitor and perform temperature calculations. Heat sensed by an infrared camera can be very precisely quantified, or measured, allowing you to not only monitor thermal performance, but also identify and evaluate the relative severity of heat-related problems.

All objects above the absolute zero temperature (0 K) emit infrared radiation. Hence, an excellent way to measure thermal variations is to use an infrared vision device, usually a focal plane array (FPA) infrared camera capable of detecting radiation in the mid (3 to 5 μm) and long (7 to 14 μm) wave infrared bands, denoted as MWIR and LWIR, corresponding to two of the high transmittance infrared windows. Abnormal temperature profiles at the surface of an object are an indication of a potential problem. Thermal imaging can detect elevated body temperature, one of the signs of the virus H1N1 (Swine influenza).

In passive thermography, the features of interest are naturally at a higher or lower temperature than the background. Passive thermography has many applications such as surveillance of people on a scene, and medical diagnosis. In active thermography on the other hand, an energy source is required to produce a thermal contrast between the feature of interest and the background. The active approach is necessary in many cases given that the inspected parts are usually in equilibrium with the surroundings.

The use of thermal imaging has increased dramatically with governments and airports staff using the technology to detect suspected swine flu cases during the 2009 pandemic. Other uses include, firefighters use it to see through smoke, find persons, and localize the base of a fire. With thermal imaging, power lines maintenance technicians locate overheating joints and parts, a tell-tale sign of their failure, to eliminate potential hazards. Where thermal insulation becomes faulty, building construction technicians can see thermal signatures that indicate heat leaks and to improve the efficiencies of cooling or heating air-conditioning. Thermal imaging cameras are also installed in some luxury cars to aid the driver, the first being the 2000 Cadillac DeVille. Some physiological activities, particularly responses, in human beings and other warm-blooded animals can also be monitored with thermographic imaging.

Advantages of thermography

* It shows a visual picture so temperatures over a large area can be compared
* It is capable of catching moving targets in real time
* It is able to find deteriorating, i.e., higher temperature components prior to their failure
* It can be used to measure or observe in areas inaccessible or hazardous for other methods
* It is a non-destructive test method
* It can be used to find defects in shafts, pipes, and other metal or plastic parts
* It can be used to see better in dark areas