How do thermal infrared detectors work?
Infrared cameras usually work in one of two ways. They either detect the infrared (IR) photons directly or they detect small changes in temperature in an array of thermal-absorbing elements. Infrared cameras that detect photons work in one of two ways: they are either photovoltaic or photoconductive. Photovoltaic means those infrared cameras use a material that produces a voltage difference when photons of a certain wavelength hit the material. Photoconductive means the infrared cameras use a material whose electrical resistance changes when photons of a certain wavelength hit it. In either case, the array of detectors sends out the signals to a readout circuit, and then, after a fair bit of signal processing, the infrared camera turns the pattern into a grayscale image. The intensity of the signal is shown in different shades of grey. At this point, colorization may be added to the infrared cameras output to ease interpretation. One of the major differences is that the materials that
