The role of LED fill light in video surveillance system
Infrared fill light is an auxiliary light source commonly used in video surveillance systems, especially when the ambient light is poor at night, the use of infrared fill light can still have a good imaging effect in extremely low illumination. There are two forms of infrared fill light in the video surveillance system: one is integrated into the surveillance camera, and the photoresistor is used to control it to turn on or off. The other is to add a separate external device at the location of the surveillance camera to provide auxiliary light sources.
Infrared fill light is a kind of LED fill light. LED fill light has the advantages of small size, low power consumption, long life and high brightness. At present, most of the fill lights on the market are composed of LED lamp beads. LED fill light In addition to infrared fill light, LED white light is also widely used. For example, electronic eye fill lights in public transport.
According to its lighting method, LED fill light can be divided into constant light and strobe light. The always-on lights are mostly used in residential areas, parks, factories and other areas that require 24-hour surveillance video. Strobe lights are mostly used when capturing images, such as electronic eye fill lights.
In the video surveillance system, most surveillance cameras integrate LED infrared fill light. Due to the low brightness of the infrared fill light itself, it will not affect the surrounding area at night. However, after the infrared fill light is turned on, the monitoring system screen will appear black and white. Of course, black and white pictures cannot meet people's requirements for video surveillance systems. Therefore, some manufacturers use low-illumination imaging or add peripheral LED fill lights to improve the problem that surveillance cameras cannot achieve color imaging at night.
The low-light imaging uses an ultra-sensitive image sensor and unique electron multiplication and noise control technology, which can greatly improve the image quality at night, and can still present colorful images in weak ambient light. The advantage is that the surveillance camera does not produce very strong light. The disadvantage is that when the ambient light exceeds the minimum illumination of the camera or there is no light source, the camera will activate infrared to ensure imaging, and the image will become black and white.
The peripheral LED fill light is not very sensitive to changes in external ambient light. Because it can compensate the light source through peripheral LEDs, etc., the full-color picture can still be presented through the LED fill light without any ambient light. However, its shortcomings are also more obvious. The brightness of the LED fill light at night is too high, which may cause serious image exposure, and may also affect the lives of nearby residents.
In fact, it is impossible for any product to be all-encompassing and perfect. The most important thing is how to use the existing technology to meet the needs of users through reasonable application. The importance of the video surveillance system solution is also reflected here.
