Why can night vision devices clearly see the environment in the dark?
It is very difficult to see clearly the environment in the dark with the naked eye alone. However, with the help of a night vision instrument, the scenery can be seen clearly without bright light or with only a small amount of weak light.
There are two commonly used night vision devices: low light level night vision devices and infrared night vision devices. At night, as long as there is a tiny glimmer of starlight and moonlight, the image intensifier tube in the low light night vision instrument can enhance the weak light reflected from the scene through photoelectric conversion and amplification. The image intensifier tube composed of a three-level amplifier board has an amplification capacity of up to 1 million times, which is sufficient to clearly reproduce the scenery in low light environments.
In environments where there is no bright light at all, infrared night vision devices come in handy. Infrared is not visible light and cannot be seen with the naked eye, but it also has the characteristics of light. Various objects in nature, as long as they are above thermodynamic zero, are -273. Above 15 ℃, infrared radiation will be emitted. The infrared image converter in an infrared night vision device can receive infrared light and display the scene through photoelectric conversion and amplification. This is a passive infrared night vision device that relies on the scene itself to radiate infrared radiation in order to see clearly the scene in the dark.
There is also an active infrared night vision device that can emit infrared light and receive the reflected infrared light from the scene, which can significantly improve the clarity of the scene.
