Night vision imaging using infrared technology
Visible light at night is very weak, but infrared rays invisible to the human eye are abundant. Infrared vision uses photoelectric conversion technology to help people observe, search, aim and drive vehicles at night. Although people discovered infrared rays very early, due to the limitation of infrared components, the development of infrared remote sensing technology is very slow. It was not until 1940 that Germany developed lead sulfide and several infrared transmission materials that the birth of infrared remote sensing instruments became possible. Since then, Germany has first developed several infrared detection instruments such as active infrared night vision devices, but none of them were actually used in World War II. There are two types of infrared vision instruments: active and passive: the former uses infrared searchlights to irradiate the target, and receives reflected infrared radiation to form an image; the latter does not emit infrared rays, but relies on the target's own infrared radiation to form a "thermal image", so it is also called "thermal image". Imager".
Infrared night vision imaging technology
Infrared night vision technology has experienced the early active infrared night vision imaging technology and the current passive infrared (thermal imaging) technology. The infrared detector was originally a unit detector, and later developed into a multi-element linear array detector in order to improve sensitivity and resolution, and has now developed into a multi-element area array infrared detector. Corresponding systems have made the leap from point detection to thermal imaging of targets.
(1) Active infrared image conversion technology (near infrared region).
This technology uses the principle of photoelectric image conversion to realize night observation. This type of instrument includes two parts: an infrared light source and a night vision goggle containing a variable image tube. The infrared light source illuminates the target, and the night vision goggles convert the invisible infrared image into a visible image.
(2) Passive infrared night vision technology (middle and far infrared regions)
Infrared thermal imaging camera is one of the most promising infrared detectors, representing the development direction of night vision equipment. It uses an internal photoelectric effect semiconductor device as a detector to convert the radiation image of the scene into a charge image, and after information processing, it is converted into a visible image by the display device
