Night vision and thermal imaging technologies: principles, applications and prospects

Night vision technology

Night vision is one of the key technologies of the 20th century. First introduced in the 1940s, it has undergone a significant evolution and has become an integral part of modern optical systems. Today, night vision devices are actively used in military, security, hunting, wildlife observation, and other fields. To evaluate the potential of this technology, we should consider its principle of operation, design features, and promising areas of development.

Night vision devices are complex optoelectronic systems consisting of many components. The main element is an electron-optical converter (EOC), which amplifies the available light and allows forming an image in low light conditions. Despite the complexity of the design, the basic principle of operation of such devices remains understandable even for users without special training.

The night vision process starts with the lens. It is the lens that performs the key function of collecting available light in low light conditions. The sources of such light can be both natural (starry sky, moon) and artificial (remote lights, infrastructure).

The light rays reflected from objects around the user enter the lens of the device. The more light that can be collected, the better the image. The collected light is focused and directed to an electronic optical converter (EOC).

The CCD is the main element of night vision. It amplifies the collected light, turning it into a visible image. There are three main generations of EOLs, as well as several intermediate options. Each generation has its own characteristics and level of efficiency. In modern devices, the second and third generations of EIS are most often used.

After the light flux enters the electron-optical converter (EOC), photons are converted into electrons. These electrons are accelerated by an electric field, which significantly increases their energy and number through the process of secondary emission.

The acceleration of electrons provides the signal amplification needed to form an image. In outdated models of night vision devices, photomultipliers were used for this purpose. Modern devices use highly sensitive photocells, in particular those based on gallium arsenide (GaAs), as well as other advanced technologies.

Photonis uses solutions such as low-noise microchannel wafers, improved photocathode coating for enhanced spectral response, and optimized anode geometry for enhanced contrast and image clarity in its ECHO and 4G series EOSs.

The accelerated electrons are directed to a luminescent anode, which has a weak electric charge. Upon collision with the anode, the electrons are again converted into photons, this time with enhanced brightness. It is these photons that form the image that is transmitted to the eyepiece and becomes visible to the observer's eye.

Night vision technologies are key to the military industry. They were originally developed for the needs of the armed forces and still remain an integral part of the equipment of army units.

Modern night vision devices provide effective surveillance in low light conditions, which is critical during reconnaissance, patrolling and combat operations. They allow you to detect the enemy, navigate the terrain and carry out targeted shooting in the dark.

Such devices are actively used by marine, ground, naval and air forces. In addition, night vision is being integrated into modern military equipment, improving controllability and combat effectiveness at night.

Night technology plays a key role in the work of rescuers. Night vision devices make it possible to conduct search and rescue operations in complete darkness, including in large areas or in conditions of limited visibility. Such equipment allows for prompt inspection of rubble after earthquakes or explosions, assessment of emergency or partially destroyed facilities, and other critical tasks. Without the use of night optics, such actions would be possible only during the day, which significantly reduces the chances of rescuing victims.

Night vision devices are also widely used in the security sector. While they used to be used mainly at strategically important facilities such as military bases, ammunition depots, or expensive resources, they are now used in most security systems. Night optics facilitate the work of security guards who control the territory of enterprises, infrastructure facilities, and prevent unauthorized access to warehouses and storage facilities. Night vision cameras are often used to provide remote monitoring of the situation in the dark and allow for rapid response in accordance with security protocols.

Night vision technologies are becoming critically important for drivers of various types of vehicles. They are being actively integrated into the control systems of modern cars, which makes driving in low-light conditions much easier.

In agricultural machinery, night vision allows you to work in the field around the clock without losing efficiency. This is especially true during sowing or harvesting, when every hour of work is important.

In cases where it is not possible to install a full-fledged night vision system on a vehicle, drivers use night vision goggles (NV glasses). They provide sufficient visibility in the dark, increasing traffic safety.

Night vision devices are widely used in aviation, both military and civilian. They are installed on the fuselage of airplanes and helicopters, as well as in cockpits, to ensure safe flight in low-light conditions.

In military aviation, modern night vision systems are being integrated to improve the efficiency of night operations. In civil aviation, they help pilots control all stages of flight, especially during takeoff and landing.

Night vision is critical for detecting obstacles:

• power lines
• high-rise buildings
• runway marking
• another aircraft in the vicinity

Unmanned aerial vehicles (UAVs) are also equipped with night vision cameras. They are used to perform a wide range of tasks, from military reconnaissance to nighttime aerial photography of public events.

Night vision devices are widely used in scientific research. Most often, they are used in zoology to observe nocturnal animals, identify new species, and assess the state of the fauna in specific regions. Thanks to their sealed housing and moisture protection, specialized models are also effective for researching the aquatic environment - lakes, rivers and seas.

In addition to zoology, night optics is used in related fields of natural sciences, such as chemistry, physics, astronomy, and ecology. The ability to work in low light conditions significantly expands the scope of field research.

Hiking enthusiasts also actively use night vision devices. This is especially true for long overnight hikes in the wild. Night optics are becoming as essential as a knife or matches. It allows you to perform tasks in the dark, from setting up a camp to navigating the terrain.

Thanks to night vision devices, you can find edible plants, berries, or nuts, and detect potential threats around your sleeping quarters in a timely manner. The ability to see in the dark increases safety and autonomy of movement.

Construction often requires the use of night vision devices. This is due to the need to perform round-the-clock work at sites to reduce construction time. During night shifts, workers need high-quality optics that can work effectively in low light conditions. This increases productivity and significantly reduces the risk of accidents.

Night hunting and fishing are impossible without night vision devices. They provide visibility in the dark, allowing you to detect animals, observe them, and determine their species, sex, and size. Modern optics also simplify aiming and reduce ammunition consumption. When fishing, night vision devices help you find promising spots, control your tackle in low light conditions, and respond effectively to bites.

Tactical games such as airsoft and paintball also benefit from the use of night optics. In the dark, it becomes a critical factor in team success. Binoculars, monoculars, scopes, and night vision cameras expand the capabilities of participants and increase the effectiveness of actions in difficult lighting conditions.

Having examined how night vision devices work and how to use their capabilities, we can now move on to analyze the key areas of development of this technology. All of them have high potential and can bring night vision to a new, more efficient level. If specialists realize the planned ideas, it will be a real breakthrough and open a new stage in the development of optical technologies.

Promising areas of development:

Not everyone knows that night vision developments are quite active. Today, this process is gradually accelerating, leading to an increase in the number of studies aimed at improving existing devices and modernizing the technology itself. Therefore, anyone interested in night vision should familiarize themselves with current developments in this area. This will help assess the prospects of the technology and the likelihood of fundamentally new solutions in the near future.

Night-vision police robots are a promising trend that is already being implemented in a number of countries. Engineers from the UAE, India, China, the US, Israel, and Congo are developing their own models of such devices, which already perform certain police functions. Although they are not yet trusted with critical tasks, their use is gradually expanding.

All models are equipped with night sights or night vision systems optimized for 1-2 specific tasks. New features are added over time, but this process requires significant resources. Among the typical tasks of police robots:

• round-the-clock traffic control on busy sections;
• informing citizens about offenses;
• receiving reports of crimes;
• patrolling the streets at night;
• scanning the faces of passersby and identifying wanted persons.

Night vision is a key component of the effectiveness of such systems, ensuring stable operation in low light conditions.

A promising area of research is to give humans the ability to see in the dark without the use of night vision devices. Although such experiments have already yielded results on rodents, human trials have not yet been conducted. Scientists are considering three potential methods to realize this idea.

The first method is to seal the DNA strands in the photoreceptor cells of the peripheral processes of light-sensitive retinal cells. Theoretically, this reduces light scattering and increases retinal transparency, which can significantly improve night vision. This approach has been shown to be effective in animals, but more research is needed in humans due to possible differences in vision physiology.

The second method involves implanting microscopic devices into the visual system. These devices are supposed to convert infrared radiation into visible light, allowing a person to see in the dark. Despite the potential benefits, the risks to the visual system do not allow us to proceed to human testing.

The third approach to realizing night vision involves the use of nanomaterials that are injected directly into the eyes. This is a transparent substance that can convert infrared radiation into light waves visible to the human eye.

The material was created using nanotechnology - it contains microscopic amounts of various chemical elements that combine to produce the desired effect without harming vision. This technology was first demonstrated by researchers from the University of Science and Technology of China (USTC) and the University of Massachusetts Amherst. They developed nanoparticles that, after injection into the retina of mice, provided sensitivity to the near-infrared range (wavelengths up to 980 nm).

Rodent tests confirmed the effectiveness of the nanomaterial and its ability to provide night vision. In particular, mice demonstrated the ability to navigate under infrared light. However, this material has not yet been administered to humans. Numerous preclinical studies are underway to assess biocompatibility, duration of effect, and possible adverse reactions.

If the results of human trials are positive, this could be a fundamentally new stage in the development of night vision technology.

Night vision systems are a key area of development for the creation of fully-fledged self-driving vehicles. Current models of such vehicles do not yet provide a sufficient level of safety, especially in low-light conditions, which significantly increases the risk of accidents at night.

The latest night vision systems are integrated directly into the vehicle's control system and perform a visual control function. When the system detects objects in the field of view, such as other vehicles, pedestrians or obstacles, it automatically activates the braking mechanism.

This allows you to quickly reduce speed and avoid collisions, which is critical for the safe operation of unmanned vehicles at night.

Companies such as Waymo (a division of Alphabet) and Aurora Innovation are already integrating infrared cameras and night vision systems into their autonomous platforms. For example, Waymo uses a combination of lidars, radars, and high-sensitivity cameras capable of operating in low light conditions. In the military sector, FLIR Systems supplies thermal imaging modules for unmanned ground platforms that are used for navigation at night and in low visibility conditions.

Integration of EOS or thermal imaging sensors into unmanned systems can significantly improve the reliability of detecting objects in the dark, which is critical for autonomous driving in urban environments.

A modern night vision system in autonomous cars includes a number of devices and sensors placed on the grille and other structural elements. They provide the vehicle's computer with access to a bright, clear, and detailed image that allows it to recognize other road users, pedestrians, animals, and obstacles on the road.

In case of insufficient natural light, the infrared illumination is activated, which improves the image quality. However, the effectiveness of such a system is limited: in adverse weather conditions (fog, rain, snow), the image quality deteriorates significantly, which can lead to erroneous decisions and emergencies.

To improve reliability, research is underway to unify the quality of night vision systems regardless of operating conditions. This is critical for the safety of autonomous vehicles and the stability of their behavior on the road.

The integration of artificial intelligence (AI) into night optics opens up new opportunities for improving image quality.

Unlike many industries where AI is implemented without a clear need, its use in night vision technologies is justified and effective. Thanks to image processing algorithms, artificial intelligence can eliminate artifacts, mask defects, and improve the overall visualization on the device's display.

Similar solutions are already being implemented, in particular, in the Photonis Lynx project, where AI is used for real-time frame-by-frame image optimization. ATN is also implementing machine learning elements in its X-Sight digital sights, which improves contrast and detail in low light.

The result is a highly detailed and clear image in low light conditions.

If this technology is successfully tested, its introduction into night vision devices (NVDs) will be implemented quite quickly. The updated optics will provide high image clarity and detail, which will have a positive impact on the efficiency of work in the dark.

The use of artificial intelligence (AI) creates new challenges for manufacturers of airborne surveillance systems. The main problem is the increase in data processing time, which leads to a delay in displaying the image on the display. In addition, the integration of AI will increase the cost of devices, making them less affordable for some users.

Theoretically, these shortcomings can be eliminated, but it will take time. It is expected that mass production of AI-enabled UAS will begin in a few years.

Thermal imaging technology

Thermal imaging is one of the most promising technologies of our time. Although it has only recently emerged as an independent field, developments in this area have been going on for a long time. Today, thermal imaging technology is actively developing and attracting considerable attention.

Before analyzing the most interesting developments, we should consider the key features of the technology, its current applications, and the main aspects that will be improved in the near future.

Many users of thermal imaging equipment do not fully understand how it works. This limits the effectiveness of the devices and makes it difficult to choose the best equipment. The principle of operation of thermal imagers is universal for all types of such optical systems.

The work of a thermal imager starts with the lens. In thermal imaging optics, it performs a key function - it collects infrared (IR) radiation coming from living and non-living objects. This is only possible when the source of IR radiation is within the range of the device. If the object is outside this range, even intense radiation will not be detected.

The infrared radiation collected by the lens is focused and transmitted to infrared detectors. These sensors have high sensitivity and can detect even faint radiation, which allows for accurate and detailed thermal imaging.

Infrared radiation undergoes a number of transformations in the thermal imaging device, resulting in a thermogram, an image that displays the degree of heating of terrain and objects on it. This thermogram is the basis for building a thermal image, which is subsequently displayed to the user.

Before being displayed, the thermogram is converted into electrical impulses that are sent to the thermal imager's electronic system. There, they are further processed and the final image is formed.

Thermal imaging allows you to detect all objects that emit heat within the field of view of the thermal imager. The heating level of each area is displayed using color gradations or shades of gray corresponding to certain temperature values.

Thermal imaging technology has evolved from a military tool to a wide range of civilian applications. Initially, it was used exclusively by the armed forces, but later it became available to the civilian sector, which significantly expanded its capabilities.

With the development of technology, thermal imagers have become in demand in many professions. They have made it possible to effectively perform complex and potentially dangerous tasks that were previously considered unattainable.

Thermal imaging optics are widely used in rescue operations due to their ability to detect thermal radiation. This makes it possible to efficiently locate people in complete darkness or behind obstacles such as bushes or structural debris.

When extinguishing large-scale fires, thermal imagers help to identify fire centers and locate victims in smoky or hard-to-reach areas. This allows rescuers to respond quickly and reduce the risk to life.

The police are also actively using thermal imaging devices, both in the pursuit of suspects and to monitor public events.

Thermal imaging technologies are widely used in medicine and veterinary medicine. They are used to create diagnostic equipment that can detect dangerous diseases at early stages. Thermal imagers are also used in non-contact thermometers that measure human body temperature without physical contact. Such devices remain relevant even after the end of the COVID-19 pandemic.

In veterinary medicine, thermal imaging diagnostics allows assessing the health of large animals such as cows, horses, elephants, etc. The resulting thermal images are highly accurate and are used as the basis for diagnosis.

Thermal imagers are also useful for hunters and tourists. They allow you to quickly detect well-camouflaged animals or spot predators in time to avoid them. When hiking in the dark or cloudy weather, thermal imaging devices help to locate other members of the group, which reduces the risk of losing a person. In addition, thermal imagers can detect the approach of wild animals.

Thermal imaging technologies are widely used in civil aviation in combination with night vision devices. They help pilots navigate in space, perform complex maneuvers in low visibility conditions, and ensure safe takeoffs and landings.

In addition, thermal imaging equipment is used by technicians to maintain aircraft. Special devices are used to check the condition of the airplane or helicopter skin - defective areas have an elevated temperature. The condition of electrical wiring and various structural elements is similarly assessed.

Without a thermal imager, such work is difficult, which increases the risk of technical errors with potentially catastrophic consequences.

Thermal imaging technologies significantly accelerate scientific research and production processes in various fields, from zoology to chemistry.

In science, thermal imagers allow:

• detect animals in the dark for observation and research;
• control the course of chemical reactions by temperature changes;
• conduct experiments with infrared radiation.

In industry, thermal imaging systems are used for:

• metallurgy - controlling the degree of heating of billets, metal temperature, and the state of thermal insulation of furnaces;
• mechanical engineering - detection of overheated components of equipment, presses, mechanisms, and temperature measurement of processed parts;
• chemical industry - monitoring the state of substances to prevent uncontrolled processes that could pose a threat to people, businesses and the environment.

Thermal imagers increase the efficiency and safety of operations in critical environments.

Modern sports actively use thermal imaging technologies. Thermal imagers have long helped judges monitor the course of competitions, especially in motorsports. Here, they are used to monitor the temperature parameters of individual components of racing cars. A similar use is observed in motorcycling.

In cycling, thermal imaging equipment allows athletes to check their bicycles for prohibited structural elements, such as hidden miniature engines that reduce the physical load on the rider during the race.

The prospects for the development of thermal imaging technologies remain relevant. Despite a certain slowdown in innovations, experts expect a new qualitative leap thanks to modern research and development. Let's take a look at the key areas of focus today and in the near future.

Advanced research and development

Developments in the field of thermal imaging technologies are ongoing. Some research, particularly in defense and medicine, remains classified, but the available information indicates that sensors, image processing algorithms, and integration with other diagnostic systems are being actively improved.

One of the key areas is the use of thermal imagers in medical diagnostics. For example, in the US and the EU, highly sensitive thermal imaging cameras are actively used for early detection of inflammatory processes, vascular disorders, and oncological changes. The devices record the body's infrared radiation and compare it with reference temperature profiles.

Medical models are equipped with sensors with a sensitivity of up to 0.01°C and a resolution of over 640×480 pixels. This ensures high accuracy and allows detecting pathologies at the preclinical stage. For example, FLIR or InfraTec systems certified for medical use demonstrate an error of less than ±0.05°C.

Thermal imaging technologies in medicine are used for non-contact diagnostics of infectious, oncological, dermatological diseases, as well as pathologies of the musculoskeletal system. Infrared thermography allows detecting local changes in body temperature characteristic of inflammation, neoplasms, or circulatory disorders. Thermal abnormalities in diabetes mellitus, diseases of the respiratory, digestive, lymphatic, reproductive and urinary systems are also recorded. Thermal imagers are used in clinical trials, physiotherapy, and sports medicine.

Thermal imaging systems in cars detect objects with high temperatures - pedestrians, animals, engines of other vehicles - in the dark or in poor visibility. They operate independently of ambient light, unlike classic night vision systems based on CCDs. In modern models, thermal imagers are integrated with other sensors (radar, LiDAR) and transmit images to the driver's display or autopilot system for real-time analysis of the traffic situation.

Modern thermal imaging systems are sometimes ineffective in conditions where there are obstacles on the road with a temperature close to the ambient temperature, such as stones or fallen trees. Due to the minimal thermal contrast, such objects are difficult to distinguish from the background for both the driver and automated systems.

The solution is to use thermal imagers with maximum sensitivity, capable of detecting even minor temperature fluctuations. This allows timely detection of objects with low thermal radiation on the vehicle's path.

However, increased sensitivity can also lead to side effects, such as increased noise or false alarms. Therefore, experts are working to find the optimal balance between sensitivity and system stability.

Quantum technologies are being actively researched for use in thermal imaging systems. One of the most promising areas is infrared photodetectors based on quantum wells (Quantum Well-Infrared Photodetectors, QWIP), which are being developed in laboratories in the US, EU and Asia.

QWIP detectors have a simple GaAs/AlGaAs heterostructure design and allow efficient detection of both mid-wave (MWIR) and long-wave (LWIR) infrared radiation. They provide high spectral selectivity and parameter stability with low noise.

Due to their quantum properties, such detectors demonstrate high sensitivity to weak infrared radiation and low dark current, which is critical for high-precision thermal imaging.

The use of quantum well infrared photodetectors (QWIP) significantly increases the efficiency of thermal imaging devices.

The integration of QWIP into modern thermal imagers allows for higher accuracy in measuring the temperature of the observed objects, which is especially important in low or zero light conditions. This opens up new opportunities for application in:

• military - for target detection and navigation at night;
• rescue operations - to find people in smoke, rubble or darkness;
• medicine - for early diagnosis of diseases using thermal imaging monitoring;
• scientific research - for accurate analysis of thermal processes;
• industry - to monitor equipment temperature and detect malfunctions.

QWIPs provide high sensitivity to infrared radiation and stable performance in mass production. This makes them a promising basis for the next generation of thermal imaging systems.

Once thermal imaging devices based on quantum well infrared (QWIP) photodetectors are fully implemented, there is a high probability of creating more versatile devices for civilian use. Such optical systems will provide images with the highest quality of the thermal profile of the environment.

This will open up great opportunities for hunters, fishermen, tourists and wildlife watchers. At the same time, the technology will have significant benefits for military units. In particular, ground forces will be able to more accurately detect hidden enemies and equipment, as well as operate more effectively in conditions of complete lack of visibility. For aviation, this development will help improve flight safety and simplify the control of manned aircraft.

Thermal imaging and night vision devices have a relatively short history of development, so it's too early to talk about reaching their technological maximum. This is confirmed by numerous studies conducted by experts around the world. They are gradually changing the perception of these technologies and bringing them closer to a qualitative breakthrough.

Thermal imaging and night vision systems have significant potential for further development.