See how video surveillance technology can guarantee the safety of modern life

Video surveillance includes front-end cameras, transmission cables, and video surveillance platforms. The camera can be divided into a network digital camera and an analog camera, which can be used as a front-end video image signal acquisition. The complete video surveillance system consists of 5 parts: camera, transmission, control, display and record registration. The camera transmits the video image to the control host through a network cable or a coaxial video cable. The control host then distributes the video signal to each monitor and recording device, and simultaneously records the voice signal to be transmitted into the recorder. By controlling the host, the operator can issue commands to control the up, down, left, and right motions of the pan/tilt and focus the zoom on the lens, and can switch between multiple cameras through the video matrix. With special recording processing mode, images can be recorded, played back, recalled and stored.

The following are the products included in video surveillance:

1) Camera (Camera)

2) Aperture lens

3) DVR

4) Matrix

5) Control keyboard

6) Monitor

In smart home systems, video surveillance systems are part of the home security system and are a common option system, especially in villa applications.

First, the classification of video surveillance

In the continuous development of video technology, video surveillance can be divided into two categories: network digital video surveillance system and analog signal video surveillance (embedded hard disk recorder system).

Second, the system interface diagram

The video surveillance system realizes the integration of video surveillance and conference, and can flexibly and effectively manage remote devices. Through the application of remote monitoring objects such as video recording, playback, linkage alarm, monitoring strategy formulation, emergency command, etc., it can achieve the dual functions of monitoring and communication, and fully meet the remote monitoring and emergency command in various fields such as transportation, water conservancy, oil field, banking, and telecommunications. demand.

Third, the history of video surveillance development

The video surveillance system has evolved in just over two decades, from analog surveillance to fiery digital surveillance to the ingenuity of network video surveillance, which has undergone tremendous changes. Now that IP technology is gradually unifying the world today, it is necessary for us to re-understand the history of video surveillance systems. From a technical point of view, the development of video surveillance systems is divided into the first generation of analog video surveillance systems (CCTV), to the second generation of "PC + multimedia card" based digital video surveillance system (DVR), to the third generation of fully IP-based network video surveillance System (IPVS).

With the continuous development of technology, wireless video surveillance systems will be one of the most widely used wireless network technologies. At the same time, with the construction of wireless cities, wireless video surveillance will certainly be one of its killer applications.

The wireless video service has high requirements on bit error rate, switching efficiency, delay, and bandwidth stability. If these aspects are not handled well, the video picture will appear mosaic, jump screen, pause, and so on. As we all know, WLAN technology is not originally designed according to telecom large-scale operation system requirements. In its basic version, there is no provision for cross-AP handover. The switching efficiency of general terminals between APs is very low. In addition, for APs and terminals for video services. There is no special processing. Like ordinary PS domain data, these factors can lead to poor real-time services such as video surveillance and voice.

Fourth, video surveillance function requirements

At present, for the monitoring system, the user's demand for its functions has been diversified and systematic. Mainly in the following aspects:

remote access. Traditional video surveillance is generally carried out on a small scale, and users generally require access to locations that are not geographically restricted and can be accessed at any time and anywhere.

Many people access the same monitoring point at the same time. Traditionally, a monitoring point is typically accessed by a monitoring center (user). The same monitoring point is likely to be accessed by multiple users at the same time, and there may be no relationship between these users. The complication of user access will require the system to enforce management of access rights.

Monitoring points tend to be dispersed while monitoring tends to concentrate. Monitoring points belonging to the same user are increasingly dispersed and are not limited by geography. For these scattered monitoring points, centralized management and control are required.

The monitoring system is required to be open and scalable. The same system should support a variety of different types of monitoring equipment, the number of users, the number of monitored points can be easily increased or decreased.

Massive data storage. Networking enables traditional local recording capabilities to be transferred to remote servers, making massive data storage possible. At the same time, the system is also required to have more powerful storage, retrieval and backup functions.

information security. The complexity of the system, the diversification of users, and the business characteristics of video surveillance itself necessarily require a strong guarantee for the system to provide information security.

Intelligent video surveillance. Future video surveillance systems will not only be limited to passively providing video images, but also require the system itself to be intelligent enough to recognize different objects, discover anomalies in the surveillance screen, and alert and provide useful information in the quickest way. In order to more effectively assist security personnel in dealing with crises and minimize false positives and false negatives, it is a powerful aid to respond to attacks and deal with emergencies. Intelligent video surveillance can also be applied to a variety of non-security related scenarios such as traffic management, customer behavior analysis, and customer service to increase the return on investment of users.

Five, system function

1. High security and image mask technology to prevent illegal tampering of video data; only authorized users can enter the system to view and call video data, and can issue management accounts with different rights to managers of different identities; effectively prevent malicious damage; Powerful log management features ensure the safe use of dedicated systems. The data transmitted between the server and the client is all encrypted.

2. The server platform is convenient to construct. In the building monitoring room, etc., the client software can be conveniently installed. Simply assign the login account with different permissions of the user, that is, the image data of the front camera monitoring point can be viewed.

3. Authority management To ensure the privacy of the Internet personnel and the security of the video data, the video surveillance system has the operation authority management, the system login and operation are strictly controlled to ensure the security of the system.

4. The remote video surveillance and monitoring personnel can remotely retrieve the monitoring images stored in the Internet cafe, and can remotely issue control commands, intelligently retrieve and play back the video data, adjust the focal length of the camera lens, control the gimbal for inspection or partial detail observation.

5, local video, save local video surveillance video data within a certain period of time, and can easily query, provide a basis for post-mortem investigation

6. Anytime, anywhere surveillance video function, no matter where you are, any password authorized user can connect to the monitoring network through the computer network around you, you can see the instant image of any monitoring network and record according to the need, avoiding the geographical interval Inconvenience caused by supervision and management.

7. The video surveillance system includes the management of the basic information of the Internet cafe, and the electronic map is combined. When the Internet cafe has an unexpected situation, the basic information of the Internet cafe (the Internet cafe contact, address, person in charge) can be obtained in a timely manner. Contact the relevant person in charge of the Internet cafe.

8, the system can be highly scalable, if you need to add a new monitoring network, add the corresponding Internet cafe information and device information on the server side.

9. The combination of Internet cafe monitoring and electronic map can more intuitively view the geographical location of the Internet cafe through the electronic map, and display the running status of the Internet cafe monitoring device in real time on the electronic map. When the user needs to view the monitoring information of an Internet cafe, Just double-click the Internet cafe on the electronic map to enter the monitoring interface of the Internet cafe.

Sixth, working principle

For the video surveillance system, the entire video surveillance system is divided into seven layers--the presentation layer, the control layer, the processing layer, the transport layer, the execution layer, the support layer, and the acquisition layer, according to the functions of various parts of the system. Of course, due to the increasing integration of devices, for some systems, some devices may exist in the system as multiple layers at the same time.

Presentation layer

The presentation layer is what we most intuitively feel, and it shows the quality of the entire video surveillance system. Such as monitoring video wall, monitor, treble alarm horn, alarm automatic barge, etc. belong to this layer.

2. Control layer

The control layer is the core of the entire video surveillance system, and it is the clearest embodiment of the system technology level. Usually we have two control methods - analog control and digital control. Analog control is an early control method. The console is usually composed of a controller or an analog control matrix. It is suitable for small local video surveillance systems. This control method has lower cost and lower failure rate. But for medium and large-scale video surveillance systems, this approach is complicated and does not have any price advantage. At this time, our more sensible choice should be digital control.

Digital control is the control core of the industrial control computer as a monitoring system. It transforms the complex analog control operation into a simple mouse click operation, shrinking the huge analog controller stack into an industrial computer, and transforming the complex and large number of control cables. For a serial dian phone line. It turns mid-range and remote video surveillance into reality and provides the possibility for remote monitoring of the Internet. However, the digital control is not so perfect, the price of controlling the host is very expensive, the module is wasted, the system may have a crisis of full-line collapse, and the control is lagging behind.

3. Processing layer

The processing layer may be referred to as an audio and video processing layer, which distributes, amplifies, divides, and the like the audio and video signals sent by the transmission layer, and organically connects the presentation layer and the control layer. Audio and video splitters, audio and video amplifiers, video splitters, audio and video switchers and other devices belong to this layer.

4. Transport layer

The transport layer is equivalent to the blood of the video surveillance system. In the small video surveillance system, our most common transmission layer devices are video cables and audio cables. For medium and long-range surveillance systems, we often use RF cables and microwaves. For remote monitoring, we usually use the Internet. A cheap carrier. It is worth mentioning that the emerging transmission layer medium - network cable / fiber.

Most people have a misunderstanding in digital security monitoring. They think that the digitally controlled video surveillance system used by the control layer is a digital video surveillance system, but it is not. The transmission medium of a pure digital video surveillance system must be a network cable or an optical fiber. When the signal comes out of the acquisition layer, it has been modulated into a digital signal. The digital signal has been running on a mature network. In theory, there is no attenuation, which ensures the lossless display of the remote monitoring image, which is unmatched by analog transmission. . Of course, high-performance returns also require high-cost investment, which is one of the most important reasons why pure digital video surveillance systems cannot be popularized.

5. Executive layer

The execution layer is the command object of our control instruction. At some point, it is not quite separate from the support layer and the acquisition layer that we will talk about later. We think that the controlled object is the execution layer device. For example: PTZ, lens, decoder, ball, etc.

6. Support layer

As the name implies, the support layer is used for the support of the back-end equipment, protecting and supporting the acquisition layer and the execution layer equipment. It includes auxiliary equipment such as brackets, shields, and the like.

7. Acquisition layer

The acquisition layer is the key factor for the quality of the entire video surveillance system, and it is also the place where the system cost is the biggest. It includes lenses, surveillance cameras, alarm sensors and more.