What are night vision devices?
Shaanxi Ireeda Protective Technology Co., Ltd.
Engineer Manager : Ms.Melin
WhatsApp: +8618291418396
E-mail: melin@ireeda.com
What are night vision devices?
Most of us have seen night vision goggles on TV or in movies, and some hunters even have direct experience using them. However, many people don't know the differences between different types of night vision goggles. Generally, it's believed that night vision goggles fall into three types:1. Image-intensified night vision device 2. Digital night vision device 3. Thermal imager. Today, we will only introduce two of them.
Low-light imaging technology
Low-light night vision technology, also known as image intensification technology, uses night vision goggles with image intensifier tubes. Low-light night vision devices utilize the low-brightness natural light reflected from targets at night, such as starlight, moonlight, and atmospheric glow, amplifying it hundreds of thousands of times to achieve a level suitable for nighttime reconnaissance by the naked eye. Low-light technology is an important component of optoelectronic high technology. In low-light night vision products, the image intensifier is the core component. It amplifies the weak natural light in the night sky, such as moonlight, starlight, and atmospheric gray light, by hundreds or tens of thousands of times to a level that allows the human eye to observe at long distances. Yellow-green light is the wavelength to which the human eye is most sensitive; therefore, fluorescent screens of this color are often used in image intensifiers. This is why the images of special forces using night vision in movies and television appear yellow-green when viewed in night vision footage.
Infrared imaging technology
Infrared night vision works by illuminating a target with an infrared searchlight and receiving the reflected infrared radiation to form an image. Infrared night vision technology is divided into active infrared night vision and passive infrared night vision. Active infrared night vision technology observes targets by actively illuminating them and utilizing the infrared light reflected from the target; the corresponding equipment is an active infrared night vision device. Passive infrared night vision technology observes targets by relying on the infrared radiation emitted by the target itself. It detects targets based on temperature differences or thermal radiation differences between the target and the background or between different parts of the target. Its equipment is a thermal imager. Currently, surveillance cameras are mostly equipped with active infrared systems, and the application of passive infrared systems is still relatively limited.
How is the detected heat transformed into an image?
Thermal imagers use radiometers to detect heat. Radiometers can measure the temperature difference between a heated object and its surrounding environment, and then use the points where this temperature difference exists to form an image.
Low-light imaging technology is widely used by militaries worldwide for night vision due to its versatility. Compared to infrared technology, it does not require infrared lamps to emit infrared light, nor does it require the observed object to possess heat. This makes it well-suited for military operations in various environments. Choosing infrared imaging technology requires considering both the wear and maintenance of the infrared lamps and whether the observed object contains heat. Low-light imaging technology, however, does not require these considerations; it can achieve night vision using only natural light.
infrared imaging technology lies in its ability to achieve night vision imaging without relying on ambient light, as it emits its own infrared light. It offers a wide night vision range and is less affected by environmental conditions. It is widely used in building surveillance cameras, primarily because it does not rely on natural light, making it suitable for indoor use. Passive infrared thermal imaging technology is unaffected by harsh environments such as rain, snow, and frost, providing clear, accurate images that can detect camouflage and resist interference. Unlike low-light night vision devices that rely on natural light, infrared thermal imaging systems generate images through the radiation from the target and background, allowing them to operate 24/7. Monitoring can be conducted even during the day using thermal imaging.
- Shortcoming
The disadvantages of low-light imaging technology lie in its susceptibility to the surrounding environment. For example, it is susceptible to strong light and exhibits halos. Night vision devices cannot operate in bright light, and observers may experience dizziness. Low-light images also suffer from poor contrast, limited grayscale levels, poor instantaneous dynamic range, flickering at high gain, and sensitivity only to reflections from the target scene, unrelated to its thermal contrast.
The drawback of infrared technology is that infrared images are only sensitive to the radiation emitted by the target scene, and not to changes in the scene's brightness. This technology relies on infrared light emitted by infrared lamps, while thermal imaging requires both the object's temperature and the intensity of the infrared radiation, making it unsuitable for monitoring in diverse environments. Furthermore, thermal imaging produces unclear images and has weak sensitivity to the surrounding environment. Infrared lamps are also prone to damage and require maintenance and replacement.
Thermal imagers are much more expensive than regular night vision devices. What are their special advantages?
Like low-light night vision devices, thermal imagers can be used in complete darkness, unlike typical image intensifier-based night vision devices which require low light to function. Furthermore, they can overcome obstacles such as fog, smoke, and vegetation, projecting clear images through them—a truly unparalleled advantage in hunting.
From a scientific and technological development perspective, infrared technology has certain advantages. Visible light exists under certain conditions, while every object is an infrared source, constantly radiating infrared radiation. Therefore, the application of infrared technology will be ubiquitous.
With the development of low-light and infrared imaging technologies, integrating and mining the feature information of low-light and infrared images to fuse them into a more comprehensive image has become an effective technical means. Night vision image fusion can enhance scene understanding and highlight targets, which is beneficial for faster and more accurate target detection in concealed, camouflaged, and deceptive military environments. Displaying the fused image in a natural form suitable for human visual observation can significantly improve the recognition performance of the human eye and reduce operator fatigue.
Ireeda is a professional manufacturer and developer of cirrus night vision devices and digital night vision devices. We have a professional R&D and production team. Feel free to send us your requirements; we can provide you with professional and rapid solutions. Contact melin@ireeda.com
Shaanxi Ireeda Protective Technology Co., Ltd.
Engineer Manager : Ms.Melin
WhatsApp: +8618291418396
E-mail: melin@ireeda.com
