Every object we see around us radiates energy in the form of infrared radiation (IR). Camera-like devices (microbolometers) detect them with their heat sensors and convert the energy information into a visual form. Infrared thermal imaging (IT) is one of the best imaging techniques that works regardless of temperature, atmosphere and lighting conditions. This is why it has gained popularity in many areas in such a short time.
Our article focuses on the use of infrared thermal cameras in various fields, including military, medical, smart cities, and security surveillance. There is also detailed information on manufacturing custom thermal imaging cameras.
Military Application of Infrared Thermal Imaging Devices
Thermal imaging technology was originally introduced for military purposes, such as motion detection in the aerospace industry and visibility in low-light conditions. The technology has now penetrated all military equipment, from individual soldiers' weapons to ground vehicles.
1. Thermal Imaging Sights
Thermal imaging sights, a type of military thermal imaging camera, identify and detect infrared energy (heat) emitted by objects. This energy is converted into an electronic image that represents the temperature distribution in the environment. They are also known as scopes when used on weapons such as rifles and machine guns.
These thermal imaging cameras contain a Focal Plane Array (FPA), which is made of special IR sensor materials. Vanadium oxide (VOx) is the newer technology and is most commonly used in military thermal imaging equipment due to its greater sensitivity and reliability. Military thermal imaging cameras allow soldiers to quickly detect and identify dangers or threats.
Most military thermal imaging cameras are cooled, meaning the sensor material must be cooled during operation. This cooled infrared thermal imaging camera allows for much more detail compared to the uncooled version and detects even the smallest temperature differences.
A high-resolution array is recommended for military thermal imaging applications. A common standard is 640 x 480 pixels, which provides a detailed image that is critical for accurately identifying targets at various distances.
In contrast to civilian thermal imaging sights, military sights are rugged and durable. They have durable outer coatings and are made from modern materials that are lightweight yet capable of withstanding harsh battlefield conditions.
Common examples of military thermal imaging sights include weapon-mounted sights for precise aiming of sniper rifles and assault rifles, handheld monoculars and military-grade thermal imaging binoculars for reconnaissance missions, and vehicle-mounted systems that provide the vehicle operator with better vision in poor visibility conditions.
2. Thermal Imaging Monoculars and Binoculars
Thermal imaging binoculars, the most common and universal type of military thermal imaging equipment, are designed for improved situational awareness and long-range reconnaissance. It features high-resolution lenses covered with advanced coatings to minimize glare and maximize light transmission.
In addition to military-grade thermal imaging technology, they feature advanced image stabilization that gives soldiers a clear, distinct view of their surroundings. Additionally, most refrigerated binoculars come with other systems built-in. For example, GPS, magnetism, and inclinometers are common in these military thermal imaging devices. Some thermal imaging binoculars are available as handheld devices, but some slightly heavier versions have a tripod.
Thermal imaging monoculars, on the other hand, are a more compact and lightweight option for soldiers who need to be agile and mobile. Despite their smaller size, these military-grade monoculars do not compromise image quality.
Military-grade monoculars are generally in the mid-infrared (MWIR) spectrum; they can provide clear images over long distances in all weather conditions. They have a solid and robust construction made of reinforced polymers. The entire body of the thermal imaging monoculars is tightly screwed to resist shock and any kind of environmental damage.
3. Thermal Imaging on Military Vehicles
The scope of thermal imaging technology also extends to armored ground vehicles such as tanks, where imaging systems and sensors are primarily used for target identification and navigation. For navigation, they have a compact system called Driver Vision Enhancer (DVE). The DVE system consists of high-resolution thermal imaging cameras that capture the heat signatures of objects and terrain. This allows soldiers to see beyond the capabilities of traditional night vision devices.
In addition to DVE, many military vehicles are equipped with Local Situational Awareness (LSA) Systems. LSA systems are a combination of thermal cameras and other sensors that work together to detect, identify and track potential threats. They provide a 360-degree view of the armored vehicle, providing occupants with important information about their immediate surroundings.
Infrared thermal imaging technology for building smart cities
In addition to military use, thermal imaging systems are also used in most practical applications – from self-driving cars to fire engines and drones.
1. Autopilot/driverless vehicles
Currently, most autonomous vehicles rely on a combination of vision cameras, LiDAR, and radar for navigation and obstacle detection. However, these sensors have their limitations. LiDAR can map the car's surroundings in incredible detail, but it becomes significantly less effective in rain or snow. Radar is more resilient in adverse weather conditions, but it lacks the spatial resolution to reliably identify pedestrians and other details. Finally, optical cameras require excellent lighting conditions to function.
Thermal imaging cameras fill this gap. They can detect far-infrared wavelengths between 8 and 15 micrometers. Since humans emit a heat signature of about 9.25 micrometers, these images can easily detect it. Additionally, imaging technology can identify vehicles based on their hotspot areas, such as: B. Exhaust pipes.
2. Fire trucks with thermal imaging technology
Fire engines that extinguish fires and rescue people during fires have a suitable thermal imaging camera. The camera module, made of fireproof materials, is located at the top of the stairs or at the highest point of the vehicle. The special feature of vehicle thermal cameras is the pan-tilt-zoom (PTZ) function.
Thermal imaging cameras are operated wirelessly from a safe distance. Firefighters can remotely adjust the camera's focus and angle to get a comprehensive view of the fire scene. People trapped in the fire are visible through hotspots in thermal imaging, allowing for faster, more efficient rescue efforts.
3. Fire monitoring
Before a fire starts, the respective region begins to heat up. Normal security cameras are not capable or strong enough to withstand and function in such critical conditions. A drone-shaped thermal camera that monitors the region detects the origin of the fire and sends it in real time to the control system so that a quick and immediate response can be carried out. Additionally, the thermal imaging drone can be paired with an alarm system that automates the fire suppression system.
4. Thermal D R a visual language
In drones, a compact, uncooled thermal imaging camera is mounted on a universal joint, which stabilizes the image and allows the lens to rotate 360°. When the drone takes off, data is continuously sent to the controller. An integrated imaging and sensor system converts thermal data into thermal images.
You also get different color modes. Hotter objects appear brighter while cooler areas are darker. This duo of drones and thermal imaging is very useful for detecting problems in difficult-to-access areas.
Search and rescue operations
Traditionally, helicopters have been used for search and rescue operations. However, they cannot reach remote areas and cannot see living things in the dark. Thermal cameras, even those mounted on drones, can detect the thermal signature of living creatures from a distance. Plus, with imaging technology, they work better regardless of weather conditions. In Vietnam, the deployment of search and rescue forces during monsoon rains and landslides is quite common.
Agricultural monitoring and agricultural production
A thermal drone not only provides an aerial view, but also a thermal image that can help farmers identify problems with their crops. For example, a thermally heated area can indicate disease and pest infestation in plants.
Maintenance and repair of building infrastructures
Underground electrical or water problems are quite difficult to detect. However, these irregularities can be diagnosed with a thermal imaging camera, which can detect temperature fluctuations even a few centimeters below the surface.
Drones carry thermal imaging devices to hard-to-reach areas, making them ideal for industrial use where safety is a priority. In Argentina, thermal imaging drones are used to inspect oil refineries. Aerial photography is taken without the need to close the facility or visit the potentially hazardous facility in person.
Species protection and environmental monitoring
The thermal imaging system can detect the heat signature of all animals. The advantage of using a drone imager is that animals can be monitored in their natural habitat without disturbing them, especially at night.
A concrete example is Switzerland, where thermal imaging drone technology is being used in an innovative way to protect calves during the cutting season. Drones equipped with thermal imaging and imaging cameras can locate hatchlings hiding in tall grass, preventing them from being accidentally killed.
Infrared thermal cameras for medical imaging
Medical thermography, a technique that uses thermal imaging cameras, is frequently used in the preclinical diagnosis of various diseases. As it is a non-invasive and contactless technology, it is effective for examining all organs and their systems.
For example, circulatory disorders and inflammatory diseases can be diagnosed based on abnormal temperature patterns. Cancerous tissue, on the other hand, generally has a higher temperature than the surrounding tissue.
In medicine, image quality is crucial. The lenses used here for medical imaging procedures therefore differ from those for other applications. They are made from chalcogenide glass by precision glass molding. They also feature an advanced anti-reflective (AR) coating that covers the entire LWIR band.
Custom Manufacturing Processes for Thermal Imaging Devices
When machining mechanical components for thermal imaging cameras, such as lens and sensor housings, frames, and plastic parts, key processes include CNC machining, molding techniques such as die casting and injection molding, and sheet metal fabrication.
CNC processing
5-axis CNC milling is mainly used to create complex geometries of thermal imaging structures and housing components. The expanded maneuverability and multi-axis rotation of 5-axis machines allow machining of complex angles and recesses that would not be possible with traditional 3-axis machines.
A T-shaped drill bit can be used to process the internal components of the thermal camera housing. This special drill press enables precise manufacturing of internal features and improves the accuracy of lens and sensor housings in thermal imaging cameras.
Pressure casting and injection molding
Die casting is a valuable process for producing metal-based thermal sensor components. It is particularly suitable for the production of parts that require high strength, precision and durability, such as: B. Protective films for boxes. Non-ferrous metals such as aluminum, commonly used in thermal sensor components, are suitable for die casting. The resulting parts are robust and precise and have an excellent surface finish.
In contrast, injection molding is predominantly used for plastic components of thermal sensors. Its versatility allows the use of a variety of plastics and polymers, making it ideal for producing lightweight yet robust sensor housing components. Injection molding is generally cheaper and faster than die casting when producing large quantities of plastic sensor parts.
Sheet Metal Processing
The housing and mechanical components of thermal imaging devices are designed for durability and protection. Sheet metal fabrication uses diverse techniques such as cutting, bending and assembly to produce durable, high-precision parts such as frames, casings and structural supports that improve strength and environmental resistance.
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Concluding
Infrared thermal imaging is undoubtedly a revolutionary technology. It was originally developed for military purposes. However, it has already penetrated a range of applications, from autonomous cars to thermal imaging drones. This expansion requires an individual design for each thermal imaging camera.
