Thermal Imaging Camera

Thermal imaging has many uses in many environments, the applications are endless and used in many sectors, including government and commercial areas. All of these applications involve the use of a thermographic camera. The appearance and operation of these modern cameras are often similar to camcorders. Often the live thermogram reveals temperature variations so clearly that a photograph is not necessary for analysis. A recording module is therefore not always built in. The CCD and CMOS sensors used for visible light cameras are sensitive only to the nonthermal part of the infrared spectrum called near infrared. Thermal imaging cameras use specialised focal plane arrays that respond to longer wavelengths. The most common types are InSb, InGaAs, HgCdTe and QWIP FPA. The most recent technologies use low cost uncooled microbolometers as FPA sensors. Their resolution is considerably lower than the optical cameras, mostly 106x120 or 320x240 pixels, up to 640x512 for the most expensive models. Thermal imaging cameras are much more expensive than their visible spectrum counterparts, and higher end models are often export restricted due to military uses for this technology. Older bolometers or more sensitive models such as InSb require cryogenic cooling, usually by a miniature Stirling cycle refrigerator or liquid nitrogen.