How Do Thermal Cameras Work Leave a comment

IRT (infrared thermography), thermal video, and thermal imaging are all examples of infrared imaging science. Thermographic cameras can usually detect long-infrared range radiation in the electromagnetic spectrum (9,000-14,000 nanometers. They also produce images of the radiation called thermograms. Thermography can make it possible to see your environment without light. The amount of radiation emitted by an object increases with the temperature. Because of this, thermography lets you see the variations in the temperature. When using a thermal imaging camera, warm objects stand out against cooler objects. Warm-blooded creatures become easy to see against most environments, during the day or night. With this in mind, thermography is very useful to the military and in surveillance cameras.

Thermal Camera Uses

A few physiological changes in warm-blooded animals can be monitored with thermal imaging. Thermography is used as allergy detection and in veterinary medicine. In alternative medicine, some practitioners promote it in use for breast screening. Government and airport personnel used thermography in the swine flu epidemic. It is currently being used against coronavirus.

Thermography has been around for a while, but its use has drastically increased with industrial and commercial applications in the past fifty years. Firefighters use it to see through smoke, to localize the base of the fire, and to find people. Maintenance technicians use thermography to locate overheating powerlines and joints, which is a sign of impending failure. Construction technicians can see thermal signatures that can indicate a heat leak in faulty insulation and air conditioning units.

Operation and Appearance

The operation and appearance of the modern-day thermographic camera are similar to a camcorder. The live thermogram often reveals temperature variations, so a picture is often not necessary. A recording module is not always built-in. Non-specialized CMOS and CCD sensors have most of the spectral sensitivity in the visible light wavelength range. In addition, by utilizing the “trailing” area of the spectral sensitivity and the near-infrared and using an off-the-shelf CCTV camera, it is possible to obtain true thermal images of objects 536 °F and higher.

Specialized thermal imaging cameras can use focal plane arrays (FPAs) that can respond to longer wavelengths. The most common types are InGaAs, HgCdTe, InSb, and QWIP FPA. The newer technologies are low-cost, uncooled microbolometers as FPA sensors. Their resolution is lower than optical cameras. Mostly at 160×120 or 320×240 pixels. The expensive models go up to 1280×1024. Thermal imaging cameras are much more expensive than visible-spectrum cameras.