The existing cameras on the market can be divided into three categories based on the use environment and light requirements: visible light cameras for daytime and well-lit environments, low-light infrared cameras for weak light conditions, and infrared thermal imaging cameras for nighttime zero illumination.
Visible light cameras can be divided into analog cameras and network cameras. At present, ordinary network cameras still occupy the majority of the market. This is mainly due to the fact that our current thermal imaging cameras are not yet fully developed. Many monitoring occasions are wired with ordinary network cables. But after all, the clarity of ordinary network cameras has gradually met the use of clear occasions. The traditional monitoring system generally has a maximum resolution of only 1080P. "Let us see more clearly" is a very urgent demand put forward by users using monitoring products, so there are network cameras. Network cameras fundamentally solve the problem of clarity, and they are easy to install, power, and browse, and have gradually replaced the dominant position of analog cameras. Network cameras have now developed into the era of megapixels. Megapixel network cameras have gradually occupied a place in the security market and continue to expand their influence. Compared with megapixel-level network cameras, the clear and delicate images give users a new visual impact.
Although all parties in the market have unprecedented expectations for megapixel network cameras, the actual use is only in some pilot projects. If 2010 is the year of the popularization of megapixel network cameras, then 2011 is the year when the charm of high-definition truly blossoms. With the maturity of product technology and closer to the field of ordinary monitoring, megapixel network cameras will surely emerge in this turbulent security market.
After solving the daytime monitoring, ordinary visible light imaging at this stage can no longer meet the monitoring of the night. The current video surveillance system mainly uses a combination of visible light cameras and manual monitoring and recording for daily security protection. However, the prevention ability at night or in bad weather is greatly reduced. How to monitor in such an environment requires the use of infrared thermal imagers.
Since visible light equipment can no longer work properly at night, the observation distance is greatly shortened. If artificial lighting is used, it is easy to expose the target. If a low-light night vision device is used, it also works in the visible light band and still requires external light illumination. It is OK to work in the city, but when working in the wild, the observation distance is greatly shortened. Infrared thermal imagers passively receive the infrared thermal radiation of the target itself, which has nothing to do with climatic conditions. They can work normally regardless of day or night, and can avoid exposing themselves. Especially in harsh climatic conditions such as rain and fog, due to the short wavelength of visible light and poor ability to overcome obstacles, the observation effect is poor or even cannot work, but the wavelength of infrared light is longer and the ability to overcome rain, snow and fog is higher, so the target can still be observed normally at a longer distance. Therefore, infrared thermal imagers are a very effective device in the field of security.
Low-light cameras only improve the sensitivity of illumination, and cannot achieve monitoring in zero illumination. They are based on visible light for imaging; thermal imagers provide thermal images by passively detecting the infrared radiation energy emitted by objects, and can clearly image without any light.
The difference between laser night vision and infrared thermal imagers
Night vision technology is a photoelectric technology that uses photoelectric imaging devices to achieve night observation. Night vision technology includes two aspects: low-light night vision and infrared night vision. Low-light-level night vision technology, also known as image enhancement technology, is an optoelectronic imaging technology that uses night vision goggles with image intensifier tubes to enhance the image of a weak target illuminated by night sky light for observation. Low-light-level night vision devices are currently the most widely used and produced night vision equipment in foreign countries. They can be divided into direct observation (such as night vision observation devices, weapon sights, night driving devices, night vision glasses) and indirect observation (such as low-light-level televisions). Infrared night vision technology is divided into active infrared night vision technology and passive infrared night vision technology. Active infrared night vision technology is a night vision technology that implements observation by actively irradiating and using the infrared light reflected by the target from the infrared source. The corresponding equipment is an active infrared night vision device. Passive infrared night vision technology is an infrared technology that uses the infrared radiation emitted by the target itself to achieve observation. It detects the target based on the temperature difference or thermal radiation difference between the target and the background or between the various parts of the target. Its equipment is a thermal imager. Thermal imagers have unique advantages that are different from other night vision devices, such as being able to work in fog, rain, and snow, having a long range, being able to identify camouflage and resisting interference, etc. They have become the development focus of foreign night vision equipment and will replace low-light night vision devices to a certain extent.
Laser night vision devices use the onick NP-1600 visible band and invisible band as illumination, and then use infrared cameras to form images, which can see anything visible to the naked eye. Infrared thermal imaging uses infrared direct imaging to only see heat imaging, and can only see outlines but cannot distinguish them, but can penetrate obstacles of a certain thickness.
