Types and main differences of common night vision devices

Active infrared night vision goggles

Principle: Infrared rays invisible to the human eye are emitted through an infrared searchlight, which are reflected back after irradiating the target. After the objective lens, the image of the target can be displayed on the fluorescent screen.

Advantages: Mature technology, low cost, clearer imaging, can work in a completely dark environment, and is not affected by ambient light.

Disadvantages: Actively emit infrared rays, easy to be discovered by the enemy, poor concealment; in addition, its detection distance is limited. The detection distance of a general rifle infrared sight is 100-300 meters, and the tank infrared sight can see vehicles 2000 meters away and personnel 1000 meters away.

Application scenarios: In the early days, it was widely used in the military field, such as sights of tanks, rifles and other weapons. Now it is also used in some civilian fields such as security monitoring and industrial detection, such as intrinsically safe infrared night vision devices for mining.

Low-light night vision device

Principle: Use the weak moonlight, starlight, atmospheric glow and other natural night sky lights at night for illumination, and use the light intensifier to amplify the weak photons reflected by the target and convert them into visible images to achieve night observation. Its core component is the image intensifier.

Advantages: It belongs to a passive imaging system, does not require an active light source, and has good concealment; it can use natural low light, can work well at night with certain light conditions, and has high imaging quality, and can provide better details and color information.

Disadvantages: It is highly dependent on ambient light and can hardly work in a completely dark environment; in addition, the image intensifier is easily affected by strong light, resulting in halo phenomenon, and its device size and weight are relatively large, which limits the large-scale equipment and wide application of some light weapon night sights.

Application scenarios: In the military field, it is widely equipped in the army, sea and air forces, such as binocular or monocular night vision glasses, helmet sights and medium-range weapon sights carried by individual soldiers; in the civilian field, it can be used for night patrols, detection, evidence collection and other work in the public security, security, armed police, customs, security and other departments, as well as photosensitivity, chemical industry, seabed resource exploration, offshore oil drilling platforms, deep-sea fishing, etc. in the industrial field. It can also be used for image acquisition and enhancement processing in the medical and health field and scientific research, such as satellite remote sensing, remote sensing of astronomical galaxies, night observation of weak stars, research on the growth law of plants at night, and research on the living habits of nocturnal animals.

Mainstream products: PVS-7, PVS-14, PVS-31, GPNVG-18.

Thermal imaging night vision device

Principle: By capturing the infrared radiation emitted by the object itself to form an image, rather than relying on reflected light or ambient light, its detector can sense the temperature difference on the surface of the object and convert these differences into a visual image. Different temperatures are displayed as different grayscales or colors on the image.

Advantages: It has strong concealment, works completely passively, does not emit any signal, and is not easy to be discovered; it can work in severe weather conditions such as complete darkness, fog, rain, snow, etc., and is not affected by light and weather; it can identify camouflage, because the temperature characteristics of different objects are different, even after camouflage, its thermal radiation characteristics are difficult to cover; it has a long range and can detect targets at a long distance.

Disadvantages: high cost and relatively expensive; the image resolution is relatively low, and the details are not as rich as those of low-light night vision devices; the detection effect of objects with no obvious temperature changes may not be good.

Application scenarios: In the military, it is widely used in reconnaissance, surveillance, aiming and other tasks, such as for discovering personnel and equipment hidden in woods and grass; in the civilian field, it can be used for fire rescue, helping firefighters find fire sources and trapped people in thick smoke, and can also be used for power inspection, industrial equipment detection, security monitoring, wildlife observation, etc. For example, some thermal imagers can be used to detect overheating faults in power lines and energy leaks in buildings.

Mainstream products: VA-MTB-900, VA-H619S, VA-T685L3, VA-T685B75.

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