As is well known, the environments in which security surveillance systems operate are highly complex: there are day-and-night changes, times when light is insufficient and times when it is too strong, scenes where overly bright and overly dark areas appear simultaneously, and transitions between indoor and outdoor settings. Faced with ever-changing and demanding conditions, choosing a network camera for the security industry is no easy task — it must satisfy a range of specific requirements. So what requirements does the security surveillance industry place on network cameras? Let the CMR editors introduce them to you below.

The security surveillance industry has the following requirements for network cameras:

1. Low illumination

Low illumination is a metric used to measure a network camera's ability to see objects clearly in dark environments. The lower the figure, the higher the camera's sensitivity and the better its performance.

Low illumination refers to a network camera's ability to still capture clear images under low-light conditions. What we call starlight-grade network cameras are one tier of low-illumination cameras, typically classified as follows:

• 0.1 Lux: twilight-level
• 0.01 Lux: moonlight-level
• 0.001 Lux and below: starlight-level

Therefore, a starlight-grade network camera is one that can display clear color images under starlight-level illumination without any auxiliary light source. It is a series of network cameras introduced to solve imaging problems under low illumination.

Infrared night-vision network cameras are mainly used in dark environments with no visible light or only minimal light. They use IR lamps to actively project infrared light onto objects; the infrared light is reflected by the objects and enters the lens for imaging. With its mature technology, wide applicability, and high cost-performance ratio, this approach has become a common application solution.

2. Wide dynamic range (WDR)

Wide dynamic range is a technology applied to make both extremely bright and extremely dark parts of a scene clearly visible at the same time. WDR technology exposes highlights and shadows separately, suppressing overly bright areas while compensating overly dark areas, so that the overall image appears relatively clear.

3. Backlight compensation (BLC)

Backlight compensation uses targeted exposure technology to ensure that the network camera fully exposes the region of interest in any environment, guaranteeing good results against strong-backlight backgrounds and allowing users to accurately capture the area they are interested in.

4. Strong light suppression

When strong light (such as vehicle headlights) enters the surveillance range, the network camera activates its strong light suppression (PLC) function, which weakens the bright areas and brightens the dark areas. It effectively suppresses the halo blooming and image blurring caused by strong light sources, achieving the desired strong light suppression effect.

5. Privacy masking

Within the camera's surveillance range, certain areas can be masked to protect privacy. For example, in an ATM monitoring area, the spot where the user enters their PIN needs to be privacy-masked.

6. Day/night switching

• Electronic day/night switching: uses a dual-pass filter; the camera's internal program switches from color to black-and-white.
• Mechanical day/night switching: uses two separate filters for day and night use, switched back and forth by a motor or coil actuator to achieve better image quality.

7. Automatic gain control (AGC)

AGC refers to the signal amplification function inherent to the camera's image sensor. Gain generally includes digital gain and analog gain: analog gain amplifies the electrical signal output by the pixels, while digital gain amplifies the signal after it has been converted into a digital signal. On one hand, the greater the gain, the greater the signal amplification and the higher the image brightness — but gain also amplifies noise while amplifying the signal. On the other hand, inappropriate gain can lead to overexposed or underexposed images. Proper automatic gain control is therefore very important to image quality. In actual operation, a network camera needs to comprehensively consider ambient brightness and sensor noise to control the gain and achieve the best image quality.

In summary, these are the requirements that network cameras for the security surveillance industry should meet. Only network cameras that satisfy these requirements can be better applied in the security surveillance industry.