Starlight Low-light Camera Technology

There are various network surveillance cameras. In terms of form, there are bolts, domes, and domes. From the perspective of functions, there are infrared, explosion-proof, and perceptual cameras. However, regardless of how they are distinguished, the first requirement is to use a security surveillance camera. "See it clearly."

According to statistics, the crime rate in the night is as high as 74.3% in all criminal cases. Difficult conditions, such as dim light and strong front light irradiation, greatly interfere with the effectiveness of night surveillance and catalyze crimes. For night surveillance, infrared cameras, laser cameras, and star-class low-light cameras are currently used in the market. Infrared and laser cameras are more cost-effective, but the defects are also obvious, such as high energy consumption, poor heat dissipation, small irradiation range, and so on. As a result, Starlight-class low-light cameras have gradually become the darling of the security market due to their powerful night-time surveillance.

One of the four factors that affect the camera's low illumination

Low-light camera, mainly affected by factors such as lens, image sensor, and back-end image processing technology, refers to a camera that can obtain relatively clear images even when the light is dark (ie, low illumination). At present, the security industry usually divides the front-end camera into four levels. When the minimum illuminance reaches or even falls below 0.0001 Lux, it reaches the “star level” ultra-low illumination camera.

1, the image sensor

The first thing that affects the low illumination of the camera is the selection of the sensor. As we all know, for an image sensor of the same size, the higher the pixel number, the smaller the light-receiving area allocated to each pixel, and the worse the low-light effect; if a 2-megapixel HD camera is used, it is the same size as a 300,000-pixel analog camera. The sensor, which has an average of only one-eighth of the sensing area per pixel, will be even worse at night.

Therefore, a star-class low-light camera generally uses an imaging sensor with a large target size: for a camera with the same pixel, the larger the target size, the more light will be absorbed into the environment by each pixel; the amount of light per unit area , is a determinant factor that reflects the low light performance of the sensor.

2, large aperture lens

The lens is an important part of the camera component. Its role in low-light monitoring application technology is to focus the camera on the target's light. The key to the low-light application and technology here is that the larger the aperture of the lens, the greater the amount of light entering the camera. Larger, that is, the increase in lens aperture can effectively increase the amount of light, so that the camera to obtain the ideal low-light effect.

3, processing chip

The low illumination environment will also bring noise to the image and thus the clarity of the image. This requires a sufficiently powerful processing chip to carry key technologies such as automatic gain and digital noise reduction.

Automatic gain can maintain the brightness of an image under low illumination in an ideal condition and control the noise level. Digital noise reduction technology can filter noise, display a more pure picture, and see more image details. The key algorithm carried by the powerful processing chip, after the raw data is “carved”, it can be presented to the user with the best image effect.

4, low illumination enhancement algorithm

Using the same processing chip does not necessarily achieve the same noise reduction and gain effects. Taking noise reduction as an example, improper noise reduction will result in serious fogging, smearing, and loss of details. For gamma setting, too high will make the contrast of the picture enhanced, the screen darkened, and the picture quality transparent, but the details will be lost; if the value is set too low, the picture will become brighter and the detail will increase, but the picture quality will be transparent. The degree is getting worse. So even if based on the same hardware platform, the final effect of the product is different, which reflects the R & D capabilities of different manufacturers.

Two-star road surveillance camera

The star-class road monitoring integrated camera, IPC123-EN, integrates a star-class illuminance camera, shield, special lens, and fill light to achieve integrated delivery. Its built-in LED fill light can supplement the license plate, and can be clearly used to distinguish the license plate on the general lighting, even the unlit urban secondary roads, branch roads and park roads.

At the same time, this camera is preset with license plate mode and provides four kinds of parameters for the speed range. The debugger no longer has to worry about setting up the cumbersome procedures of parameters such as shutter, gain, and noise reduction. It is only necessary to determine the average speed in the monitoring scene, and select the corresponding speed to set the parameters in one click.

The development trend of three low-light cameras

From the current development trend of low-light cameras, it can be divided into two major directions: horizontal and vertical. Horizontal development means to strengthen the intelligence of front-end cameras; while vertical development means pursuit of cameras to achieve lower illumination values ​​and better Image effect.

1, intelligent

From the current point of view, intelligent analysis front-end has become a trend of security monitoring. If based on the star-class low-light camera and intelligent analysis function, all moving targets in the visual field can be detected and identified in the light of morning and dusk, and the human car can be classified and input. Rich semantic information, such as color, direction, and speed, greatly improves the detection rate of night crime cases.

In addition, from a technical point of view, designing a dedicated chip to be responsible for intelligent analysis work will not affect the imaging effect of the Starlight-class low-light camera, but it can further enhance the application scope of the camera and realize the added value to the customer.

2, lower illumination

At present, the security industry usually divides front-end cameras into four levels:

Ordinary camera, the general illumination value is greater than 0.1Lux;

Low-light camera, camera with an illuminance value ranging from 0.1 Lux to 0.01 Lux;

Moonlight camera, illuminance range from 0.01Lux to 0.001Lux;

"Starlight" ultra-low illumination camera, when the minimum illumination value is even lower than 0.0001Lux.

The pursuit of lower illumination is undoubtedly the goal pursued by the industry. However, when the current technology cannot achieve even lower illumination, achieving better imaging results is also a major advance in the development of low-light camera technology.