When you first see soldiers or explorers in movies or documentaries who can still see clear images in the dark, are you curious about how the overnight vision system works? Being able to see clearly without light sounds like a situation that can only occur in science fiction novels. However, with the continuous updating of scientific facts and technology, night vision technology has also been established and continuously improved. This article will show you the questions that customers often ask us when they first learn about night vision devices. Through our answers, we will take you step by step to uncover the mystery of night vision devices.
Night vision devices, as an important application of modern optoelectronic technology, have been widely used in military operations, field exploration, law enforcement and security, as well as scientific research and other fields. For most people who are also new to the device, night vision goggles can present clear effects in the dark. Endow humans with the ability of 'night vision'. However, the vision of this technology is not as simple as intuitively imagined, but involves multiple combinations of optics, electronics, and human visual physiology.
The Visual Limitations of the Human Eye and the Demand for Night Vision
Human vision relies on two types of cells on the retina: cone cells and rod cells. At night or in low light environments, rod cells play a dominant role, but their sensitivity to light is very limited, resulting in almost no human vision in the absence of moonlight or starlight. According to a report from the National Institute of Ophthalmology in the United States, the human eye is no longer able to effectively recognize objects under illumination below 0.01 lux. Therefore, the core mission of night vision devices is to use optical and electronic technology to enhance weak ambient light, or to obtain target information through infrared technology, thereby breaking through the limits of the human eye.
How Night Vision Goggles Work: The Two Major Technological Routes of Night Vision Devices
Image Enhancement Technology
Image enhanced night vision devices are currently the most common type of equipment. The principle is to guide weak photon signals through the objective lens to the photocathode, which can convert these photons into electrons. The converted electrons are greatly amplified by the electric field in the microchannel plate, resulting in an electron flow that is thousands of times stronger than the original signal intensity. The enhanced electrons collide on the fluorescent screen, converting them into visible photons and ultimately forming an image that can be recognized by the human eye. This imaging method usually appears as a green image.
Thermal Imaging
Unlike image enhancement technology, thermal imaging night vision devices do not rely on light in the environment, but instead rely on the infrared radiation emitted by the object itself for imaging. According to Planck's radiation law, all objects above absolute zero will release infrared energy. So thermal imaging night vision devices can capture radiation signals at different temperatures through infrared detectors, convert them into electrical signals, and then process them to form pseudo color or black and white thermal imaging images. Its biggest advantage is that it can still achieve effective imaging even in completely dark environments, such as smoke, mist, or mild haze. Thermal imaging technology has been widely applied in tasks such as search and rescue, border patrol, and wildlife monitoring, especially exhibiting unique advantages in the absence of any visible light sources.
Why are Night Vision Images Mostly Green
Many users are confused when using night vision devices for the first time, why the images displayed by night vision devices are almost always green. This phenomenon is not accidental, but the result of a comprehensive consideration of the characteristics of the human visual system and device design. The reason why green is chosen as the main display color is that the human eye is most sensitive to green light with a wavelength of about 555 nanometers, which improves the resolution in dark environments and reduces eye fatigue during long-term use. Therefore, green imaging is both an engineering design result and a rational choice in physiology. Compared to red or blue, green light not only has an advantage in resolution, but also reduces visual fatigue during long-term use. Therefore, the vast majority of night vision devices choose green display in their design, forming the common image style of night vision devices today.
The Rise of Digital Night Vision Technology
With the development of the semiconductor industry and digital sensor technology, digital night vision technology is gradually entering the mainstream market of optics. Unlike traditional optical enhanced night vision devices, digital night vision devices can use high-sensitivity CMOS or CCD sensors to capture weak light signals and convert them into digital images for display on LCD screens through image processing algorithms. This method breaks through the limitation of traditional night vision devices that can only observe directly, allowing users to record and store images and videos of the scene, and can share data with other terminals through wireless transmission technology. In addition, digital night vision devices provide reliable technical support for the future integration with artificial intelligence, such as automatic target recognition, scene analysis, and intelligent tagging. Currently, most monitoring devices already have such technology integration, which improves work efficiency.
In summary, the working mechanism of night vision devices covers various disciplines such as optics, electronics, infrared physics, and human visual physiology. From image enhancement to thermal imaging, and then to digital night vision, night vision technology continuously breaks through the limitations of traditional vision, enabling humans to maintain clear observation ability in dark environments. With the development of artificial intelligence and multi fusion, future night vision devices will become more precise, intelligent, and diverse, not only continuing to play a role in military and security fields, but also showing broader application prospects in outdoor exploration and public safety.