How to distinguish surveillance cameras

High-definition network camera (IP Camera) integrates video compression and network transmission processing module (DVS) on the basis of analog camera, which has the technical characteristics of both analog camera and video server. Network cameras can run independently as long as they are placed anywhere with IP network interfaces. In addition to all the image capturing functions of general traditional cameras, network cameras also have built-in digital compression controllers and network-based operating systems (including network servers and FTP servers), so that video data can be compressed and encrypted and sent to end users through networks (LAN, Internet or wireless networks). Remote users can use standard web browser or client software on their own PC to access network cameras, monitor the situation of the target site in real time, and store image data in real time. In addition, they can also control the pan/tilt and lens of the camera through the network for all-round monitoring. Some network cameras also have other functions, such as voice intercom, alarm input, relay output, motion detection, analog video output and local storage of video data on SD card. The image is represented as follows: IP camera = one-way DVS+ camera.

Analog camera is the front-end equipment to obtain the image of monitoring site. It takes CCD image sensor as the core component, plus synchronous signal generation circuit, video signal processing circuit and power supply. In recent years, new low-cost CMOS image sensors have developed rapidly, and cameras based on CMOS image sensors have been applied to videophones or video conferencing systems that do not require high image quality. Because the resolution and low illumination of CMOS image sensor are not comparable to CCD image sensor for the time being, the camera used in TV monitoring system is still CCD camera. The signal output by analog camera is a video signal, which can only transmit one-way video signal, and it needs to be connected to a monitor or a hard disk video recorder for monitoring and recording.

According to different classification standards, the types of cameras are also different, which can generally be classified according to the following standards:

1) according to the imaging system.

According to the imaging system, cameras can be divided into PAL cameras and NTSC cameras, and PAL cameras are adopted in many countries, such as China, German, Singaporean and Australian. NTSC system is mainly adopted by the United States, Japan and other countries.

2) according to the imaging equipment division

According to imaging devices, cameras can be divided into CMOS cameras, CCD cameras and DPS cameras.

CMOS (complementary metal oxide semiconductor) camera is characterized by low price and low power consumption, but its disadvantages are short life, poor sensitivity and easy noise generation. Mostly used in early cameras. At present, some high-definition cameras are mainly CMOS.

CCD (Charge Coupled Device) camera is the mainstream at present. Compared with CMOS, it has the advantages of higher resolution, lower noise and longer service life.

DPS (Digital Pixel System) camera marks a fundamental breakthrough in camera technology. It is a cutting-edge technology to capture high-quality images. It can be used in the most complicated and harsh lighting conditions. Compared with traditional CMOS and CCD, DPS technology directly converts each pixel into a digital signal. The application of pure digital processing technology reduces the noise and loss of signal transmission.

3) according to the imaging color.

According to the imaging color, cameras can be divided into color cameras, black and white cameras and color-to-black cameras.

Color camera: suitable for distinguishing scene details, such as distinguishing the color of clothes or scenery. Because of the color, the amount of information increases, which is generally considered to be 10 times that of black and white cameras.

Black-and-white camera: used in areas with poor light and areas where lighting equipment cannot be installed at night. When monitoring only the position or motion of the scene, you can choose a black-and-white camera with higher resolution than a color camera.

Color-to-black camera: Generally, it is a low-color camera when the light is good during the day, and it is automatically converted to black and white when the light is low at night. At present, the mainstream cameras are all color to black cameras.

4) according to the camera resolution

According to the camera resolution, it can be divided into low-grade, middle-grade, high-grade and high-definition types.

Low-end type: the image pixel is about 250,000 pixels, the color resolution is about 330 lines, and the black and white resolution is about 400 lines.

Mid-range: the image pixels are between 250,000 and 380,000, the color resolution is 420 lines, and the black-and-white resolution is below 500 lines.

High-grade: the image is more than 380,000 points, the color resolution is more than or equal to 480 lines, and the black-and-white resolution is more than 600 lines.

High-definition type: the front part is the image acquisition part, that is, the high-definition network camera. At present, CCD and COMS sensors are basically designed for different needs. CMOS has certain advantages in high pixels, while CCD has better adaptability to monitoring scenes, and video coding mostly adopts H.264 and MJPEG.

5) according to the camera sensitivity

According to the sensitivity of the camera, it can be divided into the following categories:

Ordinary type: the illumination required for normal operation is1-3 lux;

Moonlight type: the illumination required for normal operation is about 0.1lux;

Starlight type: the illumination required for normal operation is below 0.0 1Lux;

Infrared illumination type: in principle, it can be zero illumination, and it can be imaged by infrared light source.

6) According to the CCD target size of the camera element.

According to the size of the CCD target surface of the camera element, it can be divided into the following categories:

The target size of 1 inch is 12.7mmX, the height is 9.6mm, and the diagonal is 16mm.

The size of 2/3 inch target surface is 8.8mmX 6.6 mm high, and the diagonal is11mm.

The size of 1/2 inch target surface is 6.4mmX wide, 4.8mm high and 8mm diagonal.

The size of 1/3 inch target surface is 4.8mmX wide, 3.6mm high and 6mm diagonal.

The size of 1/4 inch target surface is 3.2 mm wide, 2.4 mm high and 4 mm diagonal.

At present, the mainstream cameras are mostly 1/3 inch targets, and the traffic cameras are mostly 1/2 inch targets.

7) According to the appearance style.

According to the appearance style, it can be divided into the following categories:

Traditional standard: gun camera

Plate: fisheye, pinhole and other cameras.

Camouflage cameras: hemispherical cameras, lighting cameras, smoke cameras.

All-in-one machine: All-in-one machine, spherical camera, infrared camera.