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The principle of infrared light
- Apr 14, 2018 -

With conventional visible light illumination, not only can it not be concealed, but it also exposes more monitoring targets (there are disturbing people in residential areas). Covert night vision surveillance is currently using infrared camera technology. Infrared camera technology is divided into passive infrared camera technology and active infrared camera technology. Passive infrared camera technology uses infrared light emitted from any substance above absolute zero. The infrared light emitted by the human body and heat engine is strong. The infrared light emitted by other objects is very weak. Special infrared cameras can be used to achieve night-time monitoring. However, this special infrared camera is expensive and does not reflect the surrounding environment and is therefore not used in night vision systems. Active infrared imaging technology is often used in night vision systems, which uses infrared radiation “lighting” to produce infrared light that is invisible to the human eye and can be captured by ordinary cameras. It radiates “illumination” scenes and environments, and uses ordinary low-light black-and-white cameras and daylight. The color nighttime automatic black-and-white camera or the infrared sensitive low-light color camera can feel the night vision through the infrared light reflected from the surrounding environment.

Light is an electromagnetic wave whose wavelength ranges from a few nanometers (10-9m) to about 1 millimeter (mm). What the human eye sees is only a part of it. We call it visible light. The wavelength of visible light ranges from 380nm to 780nm. The wavelength of visible light is divided into red, orange, yellow, green, cyan, blue, and violet, and the wavelength is shorter than that of violet. Ultraviolet light is called infrared light, and its wavelength is longer than infrared light.

Ordinary COMS black-and-white cameras can not only see visible light but also feel infrared light. This is the use of ordinary com black and white cameras, with infrared light can be more economical to achieve the basic principles of night vision. However, ordinary color cameras cannot experience infrared light and therefore cannot be used for night vision.