A brief analysis of the four application modes of low-light night vision monitoring system

    Before setting up low-light and night vision monitoring and selecting products, you need to first understand the categories and characteristics of low-light and night vision applications. Only after mastering these categories and characteristics can you make good use of them in the corresponding environment. First of all, low-light cameras generally refer to cameras that can identify targets in low-light environments without auxiliary lighting. The principle is to use the camera's own photosensitive components Sensor, image processing unit ISP/DSP and lens optical effects together to achieve this. By applying these underlying key technologies, the application of low-light and night vision monitoring can produce actual performance, and its implementation methods are not unique, and generally include the following categories.

    The most convenient day color/night black and white mode (Day/Night Mode)

    Also known as day and night mode, this type of camera is gradually becoming mainstream in the market by using the principle of electromechanics. The low-light performance of general day and night cameras is indicated by the mode of 10-2Lux for color and 10-3~10-4Lux for ICRon black and white. The indication of 0Lux is basically meaningless, so it must be specially stated when it is used for day and night monitoring under low-light night vision conditions. This type of camera uses the high sensitivity of black and white images to infrared rays. Under specific light conditions, it uses the electronic mechanical circuit to switch the filter ICRCut or directly switch to black and white signals, that is, after sensing infrared rays, the image is converted from color to black and white mode. In the process of color/black and white line conversion, because the infrared filter is removed, the imaging focus of the picture changes, so it must be matched with an IR lens to keep the focal length of day and night imaging consistent, so as to avoid the shortcomings of blurred image focal length and incorrect color performance. Based on this, although this type of camera has become a purchasing trend, the "disadvantage" of additional cost increase caused by the additional IR lens cannot be avoided, and strictly speaking, this mode is not the most ideal low-light and night vision application method.

    The most commonly used low-light high-sensing mode (Low-LightMode)

    Also known as low-light full-color mode, this type of camera mostly uses SuperHAD, Ex-view/EXTRA-ViewCCD or back-illuminated COMS as photosensitive components, and has good visible light and near-infrared light response in low-light environments. Cameras that use this technology are also called all-weather cameras. Usually, the low illumination of its low-light color mode can reach 10-2Lux, and it can reach 10-3Lux in black and white. It can be used under 0Lux with infrared auxiliary lighting, but the illumination in the latter two situations does not constitute the requirements and modes of low-light color conditions. This type of surveillance camera can not only clearly identify images, but also maintain a certain noise value to present color images in low light, and there is no delay and tailing of the picture when low-light display is achieved through the slow shutter speed light accumulation method.

    The most risky slow shutter mode (Digital Slow Shutter)

    Using the DSS electronic slow shutter, a large amount of light is allowed to pass through the aperture shutter to accumulate a higher picture illumination effect, which is also called light or frame accumulation. This type of frame accumulation camera uses slow shutter technology to accumulate the blurry images due to insufficient light to form a clear image. Under the premise of an aperture of f1.2-1.4, the picture can accumulate enough illumination frames. This technology can reduce the camera illumination to 10-4Lux. An article mentioned that this is a stupid but reliable low-light application technology, but this technology is only suitable for fixed cameras and requires constant changes in ambient light. Otherwise, it is easy to cause image delays. It is suitable for static monitoring places such as those where infrared or projection lights are disabled.

    The last resort infrared auxiliary lighting mode (IRIlluminationMode)

    Also known as infrared camera (IRCamera), it is currently the best low-light and night vision application besides day and night conversion camera. It can also be divided into two types: built-in IR light and external IR auxiliary projection light. Because CCD and CMOSSensor photosensitive components can sense most of the visible light and infrared light spectrum range, it can assist infrared light illumination to make the image sensor sense clearer images when there is no visible light at night.

    At the same time, the camera's photosensitive components have higher light sensitivity in black and white mode than in color mode, and can capture clearer images in dark environments. Therefore, with the auxiliary lighting of infrared lights, it can be used for monitoring applications under 0Lux environmental conditions. In addition, through the automatic on/off device of the photoresistor, you can also choose to use a black and white or day and night camera to increase the monitoring application capabilities of low light and night vision.

    The above four categories of products can be used as the basis for application modes when selecting low-light and night vision surveillance systems, and can be used as a reference for selecting related products. After discussing the selection issue, we will further discuss how to install and construct related products to achieve the best results.