Video Surveillance Technology FAQ

Video surveillance is the most important module in the security industry. It has more popular applications than other sectors, but it has evolved from single to dual and from small to many. With the use of video surveillance and the development of product technology to a wider and broader field, video surveillance has become a concern for users. To this end, experienced experts answer us.

Multiple developments in the scope of video surveillance applications

At the same time, we also noticed that the traditional video surveillance service is very narrow in terms of geographic coverage and user group coverage. This year, the development of video surveillance presents some features different from the past, and gradually extends to large regions and multiple fields. The scope of application is broader and more comprehensive.

1. From individual industries to multiple domains

In the past, China's video surveillance applications were mainly concentrated in government departments and special departments and industries such as finance, public security, transportation, and electric power. Among them, the government sector and the financial industry accounted for 20.9% and 20.6% respectively. However, with the advancement of social informatization, the demand for video surveillance in more and more industries and fields has increased significantly. Even traditional users such as public security have put forward new patterns and functional requirements for urban surveillance in the “safe city”. . This year, video surveillance began to extend from individual areas such as banks and transportation to multi-disciplinary areas, from traditional security monitoring to management monitoring and production management monitoring.

In addition, video surveillance is only being used in the enterprise industry, and public households have become a new market for video surveillance applications in 2008. In the public home market, video surveillance is mainly applied to residential security and property monitoring. Users can install a camera at home and use the home gateway as a video server. Users can monitor home security remotely through the Internet. Although it is far from the full realization of the digital home, with the development of IPv6 technology and information appliance technology and the further optimization of mobile monitoring equipment, video surveillance technology is likely to be first promoted in the digital home. A domestic market research report pointed out that as individual users pay more attention to family safety, the awareness of using video surveillance systems to ensure residential security is significantly strengthened, and will become an emerging market in 2008.

2. From local monitoring to cross-provincial spanning

The market for video surveillance needs continues to expand. In addition to traditional industries, corporate and personal markets are also emerging. The most active SMEs and individual users in China's economy have clearly demonstrated their application prospects for video surveillance. At the same time, the requirements of users are getting higher and higher, the most prominent of which is the requirement to realize real-time, non-geographical and unimpeded transmission of large amounts of video data, thereby achieving resource sharing and providing convenience and quickness for managers and decision makers at all levels. Effective service.

Especially for some large group companies, these enterprises are cross-provincial, with branches all over the country, and activities between branches are very frequent. If people from all walks of life go back and forth, it obviously reduces work efficiency and wastes. Enterprise resources have increased operating costs. Through video surveillance, you can realize the situation of the company in a timely and intuitive manner when you are in different places. Therefore, these customers are also in urgent need of connecting video surveillance systems across the province and the whole country. Many large enterprise groups, including Haier Group, are required to cross-provincial inter-regional connectivity when expanding their video private network. This shows that powerful and international enterprise groups hope to expand the coverage of video surveillance systems and improve their coverage. Efficiency and cost reduction. It can be foreseen that breaking through the limitations of the local network and realizing intra-provincial or inter-provincial networking will be an important trend in the development of video surveillance platforms in 2008.

3. From providing access to system integration

At present, telecom enterprises in many places only provide network channels for users when constructing video surveillance systems, and cannot participate in terminal procurement, software installation, operation and maintenance. In this mode, users need to purchase video terminal equipment by themselves, build their own information management software system, and entrust a third party to maintain the system and line. This not only increases the difficulty for users to use the business, but also makes the video surveillance system effective. Greatly reduced.

To this end, experts pointed out that telecom operators should become experts in information technology. When developing video surveillance services, they should use broadband networks to network dispersed and independent image collection points to achieve unified monitoring and unification across the region. Storage, unified management, integrated utilization of industry resources; can not only provide channels, but also system integration, should provide integrated packaged services from hardware to software, from construction to maintenance.

Video surveillance presents five major trends in the future

The use range of video surveillance presents different trends. In many aspects, the development of the whole field, the development of video surveillance technology itself also presents five major development trends.

First, technological innovation will eliminate backward-capacity small and medium-sized enterprises.

The video surveillance system will develop in the direction of “digital, networked, integrated and intelligent” technology. From the current technological development trend of the market products, the analog cameras will be replaced by digital cameras, and the digital cameras will also be networked and integrated. Intelligent development, greatly expanding the application range of video surveillance, making business and technology more closely linked, and the continuous improvement of enterprise technology level will inevitably eliminate small and medium-sized enterprises that rely on counterfeit and pirated mainstream products.

Second, the scale of the enterprise will help improve the industry standards.

At present, the internal system of the domestic video surveillance industry is still not perfect, bringing many obstacles to the development of the industry. In addition, although the number of enterprises in operation is huge, most of them belong to small and medium-sized enterprises, showing the status of “more and weaker”. In addition, the lack of core technology has led to low overall value-added of the industry. However, with the strength of many powerful enterprises, the continuous breakthrough of core technologies, and further consolidate the market position and competitive advantages of enterprises, it will also promote the further improvement of industry standards such as SVAC, ONVIF, PSIA and other enterprises.

Third, leading enterprises drive domestic industries into line with international markets.

The domestic video surveillance product development and production level is increasing day by day. More domestic enterprises will have the strength to participate in international competition, and the proportion of overseas sales will be further improved. In the meantime, domestic enterprises will directly compete with international enterprises, prompting domestic enterprises to continuously narrow the gap between themselves and international enterprises in technology, service, marketing, etc., and drive domestic industries to meet the international market.

Fourth, the transformation of equipment manufacturers will optimize the industrial business model

In the construction of video surveillance projects, more security needs, more and more attention to the system's technical support, daily maintenance and later update and upgrade. In response to the “one-stop demand” of end users, many equipment manufacturers have turned to provide customers with overall monitoring system solutions, from traditional equipment manufacturers to overall solution providers, and the business model has been transformed from supply single equipment to system construction plus operation and maintenance. The service model further promotes the optimization and adjustment of the industrial structure.

Fifth, intelligent analysis will greatly increase the added value of the industry.

The intelligentization of video surveillance has become the future trend of the industry development. It can extract and filter video in real time, and issue early warnings, which completely changes the passive state that traditional monitoring can only be “supervised” and cannot be “controlled”. At present, more and more technology-based enterprises in China are focusing on the development of core technologies such as digital signal processing and video analysis algorithms, which will greatly increase the added value of the video surveillance industry and improve the development bottleneck of the existing industry value.

Experience: Video surveillance common problems and solutions

With the popularization and application of video surveillance, some small problems are often encountered in the process of use. For different fault situations, corresponding measures should be taken to solve the problem. For this reason, we specially consulted experts with rich engineering experience to talk to us. Talking about common faults and solutions in video surveillance.

1. Because the connection between the equipment of the monitoring system involves many lines, if the processing is not good, especially if the line connected to the main equipment is improperly connected or connected incorrectly, there will be disconnection, short circuit, poor insulation between the lines, miswired, etc. The problem that causes the performance of the device to drop or even be damaged. In this case, it should be analyzed and checked according to the fault phenomenon to determine which faults may occur when there are problems with the line connection. In addition, it should be noted that the connection between each system equipment and various lines should meet the requirements for long-term operation of the monitoring system.

2. The characteristic impedance mismatch of the transmission cable may cause several vertical strip interferences with equal spacing on the monitor screen, and the frequency of the interference signal is substantially an integer multiple of the horizontal frequency. This interference phenomenon is caused by the fact that the characteristic impedance and distribution parameters of the video cable do not meet the requirements. For such interference, the impedance of each device in the system should be matched as much as possible. Especially when purchasing video cables, ensure the cable quality and, if necessary, sample the cables.

3. The parameters such as the communication interface or communication protocol are not set. This situation often occurs between the control host and the device with communication control relationship such as decoder or control keyboard. That is to say, the selected control host and decoder or control keyboard are not caused by parameters such as communication protocol during project installation. Therefore, the host, decoder, control keyboard, etc. should pay attention to the communication protocol and other parameters during installation. Settings.

4. Common faults of video interference.

* A black bar or white bar appears on the monitor's screen and scrolls up or down, which is the so-called 50HZ power frequency interference. This kind of interference is caused by the improper connection of the front end and the control center to form a potential difference loop into the system, and may also be caused by the power supply performance degradation of the device itself.

* The image has snow noise, which is mainly caused by signal attenuation on the transmission line and coupling of high frequency interference.

* Video images have ghosting, or the image is whitish, the characters are dithered, or several vertical bars of equal spacing are generated on the monitor's screen. This is because the characteristic impedance between the video transmission line or the device is not 75Ω, resulting in impedance mismatch.

* Twill interference, jitter disturbance, power supply interference. This kind of interference does not overwhelm the normal image when it is slight, but it severely distort the image and cannot be viewed. The reasons for this are more complicated and complicated. For example, the quality of the video transmission line is not good, especially the shielding performance is poor, or the power supply of the power supply system is cluttered, or there may be a strong interference source near the system.

* Large area of ​​moire interference, also known as single frequency interference. This phenomenon is mainly caused by a short circuit of the video cable and a short circuit of the screen, a fault caused by an open circuit, or a poor contact with the BNC connector.

5, the equipment failure caused by power problems, there are mainly the following possibilities:

*The power supply line or power supply voltage is incorrect;

*The power is not enough (or the wire diameter of a certain power supply line is sufficient, the pressure drop is too large, etc.);

* Short circuit, open circuit, instantaneous overvoltage, etc. of the transmission line of the power supply system.

It should be noted that damage to the equipment may occur due to power supply errors or transient overvoltages. Therefore, before power supply, we must carefully check and check carefully, and must not be taken lightly.

6. Fault caused by short circuit and open circuit of the core wire of the video cable and the shielded cable. This type of failure is manifested by the generation of deeper and more chaotic large-area moire on the monitor, so that the image is completely destroyed and images and synchronization signals cannot be formed. This is often the case with BNC connectors or other types of video connectors. That is to say, when such a fault occurs, it is often not a problem with the entire signal line, but only on the number of paths where the connectors are not good, as long as the connectors are carefully checked one by one, it can be solved.

7. Space radiation interference introduced by the transmission line. This kind of interference occurs mostly because there is a strong and high-frequency spatial radiation source near the transmission system, the front end of the system or the central control room. The solution to this situation is to build a system to achieve a comprehensive understanding of the surrounding environment, and then try to avoid or away from the radiation source; secondly, when the radiation source cannot be avoided, the front end and the center equipment are strengthened. The pipeline of the transmission line is made of steel pipe and well grounded.

8. The failure of the gimbal

The common faults of the gimbal are not working well or cannot be rotated at all after use. This situation is generally caused by the following reasons, in addition to product quality reasons:

* Only the head mounted to the camera is allowed to be lifted during use. The hoisting method leads to an increase in the operating load of the gimbal. Therefore, the use of the gimbal will cause damage to the transmission mechanism of the gimbal and even burn the motor.

* The total weight of the camera and its protective cover exceeds the weight of the gimbal. Especially for the outdoor use of the gimbal, the weight of the protective cover is often too large, and the problem that the gimbal can not turn (especially in the vertical direction) often occurs.

*The outdoor head is faulty or even damaged due to poor ambient temperature, low temperature, or poor performance such as waterproof and antifreeze.

* When the distance is too far, the operation keyboard cannot remotely control the camera (including the lens) and the pan/tilt through the decoder. This is mainly because when the distance is too far, the control signal is attenuated too much, and the control signal received by the decoder is too weak. At this time, a relay box should be added at a certain distance to amplify the control signal.

9. The matrix host does not clean the image. This type of fault is generally manifested on the screen after the selection, such as superimposing other picture interference, or interference with other lines of the line sync signal. The quality of the matrix switch is poor, and the isolation between the images is not achieved. If the RF transmission system is used, it may also be caused by excessive modulation and mutual modulation of the system.

10. The image contrast of the monitor is too small and the image is light. This phenomenon is not a problem with the control host and the monitor itself, that is, the transmission distance is too far, causing the video transmission line to attenuate too much. In this case, the line amplification and compensation device should be added.

11. The image clarity is not high, and the details are lost. In severe cases, color signal loss or color saturation may be too small, which is caused by excessive loss of the high frequency end of the image signal, that is, the loss of the frequency signal above 3 MHz. In this case, the high-frequency signal is too large due to the long distance of the transmission, and there is no amplification compensation device in the middle; or because the distributed capacitance of the video transmission cable is too large; or because the transmission line has appeared between the core line and the shield line of the transmission line. A concentrated distribution of equivalent capacitance.

12, color distortion. This is a phenomenon that is prone to occur in long-distance video baseband transmission. It is also mainly caused by the transmission line being too long, causing the attenuation of the high frequency band of the signal to be too large. In this case, a compensator should be added.

A large-scale TV monitoring system that operates in conjunction with anti-theft alarms is a highly technical and complex system. Although various failure phenomena may occur, as long as the quality of the equipment and equipment is selected and strictly constructed according to standards and specifications, there will be no major problems. Once a problem arises, as long as you are calm and analytical, you can solve the problem faster.