Working principle of laser night vision instrument

There are two types of night vision devices: active and passive. Active night vision systems use near-infrared light as a light source to illuminate targets, such as infrared LEDs, infrared lamps, and near-infrared lasers. Use a low-light camera or low-light camera to receive the infrared light reflected by the target, convert it into a video signal, and display the image on the monitor screen synchronously. This kind of night vision device is called an active infrared night vision device.

There are two types of passive night vision systems:

One is to use all very weak natural light such as moonlight, starlight, sky glow, night sky light, etc., to enlarge and enhance it to achieve the purpose of visibility. This type of night vision device is also called low-light night vision device.

The other is to use far-infrared sensitive detectors to detect the thermal radiation of the target itself. This type of night vision device is also called thermal imager. Under the condition of passive imaging measurement under natural light illumination, due to the influence of various background radiation, the imaging system's ability to image measurement and accurate tracking of long-distance targets is limited.

Using laser active illumination to illuminate distant, small and dark targets or their parts can reduce the influence of background radiation and improve the system's precise tracking and imaging measurement capabilities for long-distance, small and dark targets.

The working principle of the laser active illumination imaging system is to illuminate the entire target or key features of the target by adjusting the focus state (divergence angle) of the emitted laser beam to meet the detection requirements of the receiving system and achieve the purpose of imaging and observation of the target. Active laser night vision devices have low cost, easy to use, high spatial resolution, can be used day and night (can also be used during the day), have a relatively long detection distance, and can identify target camouflage to a certain extent. Therefore, it is very suitable for applications such as public security, armed police and border line monitoring. Laser night vision device mainly studies active laser illumination infrared night vision device to achieve the purpose of detecting targets at night. The night vision goggles are mainly used for military or paramilitary application purposes.