Night vision systems use infrared images to detect and obtain images of objects that are difficult to see in the absence of sufficient visible light. There are two main categories of car systems of night vision, active and passive. Active night vision systems use infrared light to illuminate dark surroundings, while passive systems are based on thermal radiation of humans, animals and other objects at temperatures that are different from the ambient temperature.
Night vision system
Active night vision systems operate in the infrared wavelength range near the visible spectrum (0, 7 – 3, 0 μm). These systems have their own source of infrared light, which illuminates the objects at a considerable distance in front on the road, where the headlights cannot achieve. The reflected infrared light is captured using infrared chambers. Light is radiated by these systems, in two forms, closed type, and not by breeding. Closed type systems emit infrared light pulses, while the unhealthy type of system radiates constant infrared light. Active night vision systems provide clear monochromatic images of the road in front and its environs.
Passive night vision systems operate with longer infrared waves than active systems (8 – 12 μm). They detect thermal radiation emitted to humans and animals using thermal imagers. They are not able to detect obstacles at the temperature of the surrounding atmosphere. Passive systems can usually detect objects over long distances compared to active systems and it is better to see through the fog.