All the secrets of night vision technology

After the first night, vision devices were introduced, and skepticism quickly gave way to excitement. This equipment revolutionized the world and opened up new possibilities for humanity. In the years since, night vision has evolved and has now become a vital technology. 

NV works in the dark

Those who have used various NVDs for a long time know the saying that night vision doesn't work in complete darkness. Unlike thermal imaging binoculars and other similar devices, NV can't obtain enough initial "information" to form a clear image in such conditions. However, this doesn't mean night vision is entirely ineffective in the dark. Night-vision-enabled devices capture minimal starlight and moonlight. The collected data is processed exactly as in more favorable lighting conditions, but because the available light is meager, only a dark spot appears on the screen.

Green is not a random color choice

Almost all devices using NV technology produce a green image. This color was deliberately chosen for three main reasons. The first is a characteristic of the visual system. The human eye distinguishes many more shades of green than any other color. This means that a green image will always be more informative. The second reason: human eyes become much less tired when looking at a green image, allowing they to observe for longer. The third reason is the enhanced perception of this color. The human brain processes information presented in green more quickly and can more accurately identify various nuances of observed objects.

IR illumination makes the user visible

Humans cannot see in the infrared spectrum without specialized optics. But IR illumination used in many NV devices makes the user visible. This means that people equipped with night-vision optics will instantly notice the user, even at great distances. 

NV is sensitive to bright light

Bright light can damage or reduce the performance of the NVD's primary component—the image intensifier tube (IIT). 

It is impossible to eliminate image noise

Some unscrupulous optics manufacturers attract buyers with claims that their devices can produce noise-free images. This marketing ploy is effective, as many, even experienced users, remain unaware that noise cannot be eliminated. It results from various factors that people have not yet learned to eliminate. Insufficient photon counts, background radiation from the IIT device, and nuances of the light amplification process are just a few of the causes of noise. Today, such defects are the norm, and their incidence depends on the environmental conditions in which NV optics are used.

Night vision is ineffective in poor weather

The key feature of this technology is that it only amplifies reflected light. This means that, in the presence of any obstacles, performance drops and the image becomes less informative or even unusable. Fog and rain pose the biggest challenges for NV technology. Both of these conditions produce small water droplets that scatter light, causing distortion. 

NVDs perform worse in cold weather than at normal temperatures

Some users are unaware that virtually all devices perform less efficiently in cold weather than at comfortable temperatures. Night vision optics are no exception. At low temperatures, the IIT operates more slowly, meaning the light amplification process takes longer. This leads to delays in displaying images and other unpleasant consequences. The cold also impedes the electronics that ensure compelling night vision. They frequently malfunction and are unable to cope with their tasks quickly. Increased noise is another consequence of low temperatures, resulting in less clear images even under optimal lighting conditions.

Digital NV is slower than analog ones

The era of digital night vision has arrived. It offers numerous advantages over analog and is increasingly becoming a preferred option for users. However, many are unaware that digital night vision is slower than its older competitor. The difference is minimal, but in some cases it can cause problems. For example, even the fastest digital NVD sensors create a 20-30 ms delay. This doesn't affect image perception during leisurely scanning. However, if you need to see clearly while walking, running, or driving quickly, digital night vision will be impossible. Due to the short delay, the image will become blurry, leaving only the most significant objects visible.

NV technology distorts the distance and size of objects

Most beginners have a serious problem judging the size of objects they see with night vision. This is because NV optics slightly distort reality, and what appears small on the screen is actually larger. Only experienced users who have repeatedly performed various tasks in the dark know this secret. In addition to size, night vision slightly distorts distance perception. Objects on the display appear farther away than they actually are. Depending on the NVD model used, the difference can be over 20%. Because of this, users will have to get used to their optics and estimate size or distance using other methods.

Dust is a massive problem for night vision

Many people know that moisture negatively impacts the performance of night vision devices. But few realize that dust also has a similar effect. Fine dust particles in the air create a fog-like effect that interferes with NVD imaging. When objects are observed at a great distance, night vision becomes virtually useless. It cannot "see" through dense fog and cannot provide the user with a clear view. Dust also damages various components of NVDs. The IIT and other key elements that enable night vision are coated with fine particles, often leading to failure.

Night vision is a unique development that has rapidly advanced and become indispensable to humanity. Throughout history, this technology has not revealed all its secrets to humankind, remaining a mystery. However, today, everyone has the opportunity to learn more about night vision and rediscover it.