Front-end and back-end equipment can be constructed in many ways, and their connection (also called transmission system) can be realized by cable, optical fiber, microwave and so on.
Development history
Video surveillance system has only developed for more than 20 years, from analog surveillance to fiery digital surveillance to 20 12 emerging network video surveillance, earth-shaking changes have taken place.
Today, with the gradual unification of global IP technology, it is necessary for us to re-understand the development history of video surveillance system.
From the technical point of view, the development of video surveillance system can be divided into the first generation analog video surveillance system (CCTV), the second generation digital video surveillance system (DVR) based on "PC+ multimedia card" and the third generation video surveillance system (IPVS) based on IP network.
The first generation of video surveillance: The traditional analog closed-circuit surveillance system (CCTV) relies on special equipment such as cameras, cables, video recorders and monitors.
For example, a video camera outputs a video signal through a dedicated coaxial cable.
The cable is connected to special analog video equipment, such as video image splitter, matrix, switcher, video recorder (VCR) and video monitor.
Analog closed-circuit television has many limitations: the limited monitoring ability only supports local monitoring and is limited by the transmission length of analog video cable and cable amplifier.
Systems with limited scalability are usually limited by the input capacity of video image splitters, matrices and switches.
Users who have the burden of video recording must take out or replace new videos for storage, and videos are easy to be lost, stolen or inadvertently erased.
The video quality is not high. Video is the main limiting factor.
Video quality decreases with the increase of copy number.
The second generation of video surveillance: The current "analog-digital" surveillance system (DVR): The "analog-digital" surveillance system is a semi-analog-digital scheme with DVR as the core. Video signal is still output from camera to DVR through coaxial cable, which supports simultaneous recording and playback of video and limited IP network access. Due to the variety of DVR products and the lack of standards, this generation of systems is a non-standard closed system, and there are still a large number of DVR systems.
Complex wiring "analog-digital" scheme still needs to install a separate video cable on each camera, which leads to complex wiring.
The typical limitation of DVR with limited scalability is that it can only expand 16 cameras at a time.
Limited manageability still requires external servers and management software to control multiple DVRs or monitoring points.
Limited remote monitoring/control capability still makes it impossible to access any camera from any client.
You can only access the camera indirectly through DVR.
Risk of Disk Failure Compared with RAID redundancy and tape, "analog-digital" video is unprotected and easily lost.
Third Generation Video Surveillance: Future All-IP Video Surveillance System (IPVS): Compared with the first two schemes, all-IP video surveillance system has significant differences.
The advantage of this system is that the camera has a built-in Web server and provides Ethernet port directly.
These cameras generate JPEG or MPEG-4 data files, which can be accessed, monitored, recorded and printed by any authorized client anywhere in the network, instead of generating images in the form of continuous analog video signals.
The Third Generation All-digital Monitoring System
The third generation video surveillance system relies on the network, takes the compression, transmission, storage and playback of digital video as the core, and features intelligent and practical image analysis. It is perfectly integrated with alarm system and access control system on one platform, which has triggered a technological revolution in the video surveillance industry and quickly attracted the attention of the security industry and users.
Compared with the first generation of traditional closed-circuit television monitoring system (CCTV) and the second generation of semi-digital monitoring system (DVR), the third generation of monitoring system is based on TCP/IP network protocol and appears as a distributed concept, which expands the monitoring mode to the complementarity of decentralization and centralization and infinitely expands the monitoring scope.
In terms of hardware equipment, the third generation system adopts more advanced D/A, A/D conversion equipment, video server or network camera with built-in processor, and sets up image processing (acquisition, compression, protocol conversion and transmission) at the monitoring point, and uses the ubiquitous Internet and local area network to realize plug-and-play in the whole network, realizing the whole process of image acquisition, transmission, video recording and final output, which makes the system more uncertain.
Especially when the site environment is harsh or it is inconvenient to enter the site directly.
It can perfectly solve the cross-regional monitoring needs. In practical application, due to the increasing demand, the security system often needs to be expanded. The pre-planning and the consideration of expected capacity are directly related to the future expansion cost.
Generally speaking, every component of a system may become an unlimited number of expansion costs in the future. The more components, the greater the uncertainty and the more difficult it is to control the cost.
Therefore, under the premise of sufficient system capacity, the traditional CCTV system cannot predict the cost of each new monitoring point, but the third generation all-digital monitoring system can predict and master it.
Digitalization is the future trend.
Browser has become the most accepted front-end application tool in the software industry today. Browser is the simplest and most popular front-end application in Intra and Inter environment, especially accessing Inter through wan. In order to share the resources of the enterprise, the application system should support the browser interface.
Wiring itself is a huge hardware project, and the cost of management and expansion is increasing day by day.
With the progress of information engineering technology, traditional application systems can now be digitized and then executed on this framework.
Therefore, when evaluating the introduction of a new system, whether the existing IT architecture can be used to save huge wiring costs has become an important consideration.
To sum up, a complete system design must consider important factors including compatibility, integration and inclusiveness between the new system and the old system.
Market Status of the Third Generation All-digital Monitoring System
Digitalization is the future trend, and browser has become the most accepted front-end application tool in the whole software industry.
Webcams and video servers have entered the China market for four or five years. Although the concept of "networking" has long been deeply rooted in people's hearts, the popularization and application of these networked products is hard to say.
In the process of market development of network cameras and video servers, some early-invested manufacturers have paid a lot of hardships and detours. Until 20 12, especially since the release of MPEG-4 standard in February 2002, network cameras and video servers have entered a stage of vigorous development, and the market recognition and demand have also been greatly improved.
Since the development of monitoring system, in addition to the continuous innovation of monitoring technology, monitoring products have also begun to form a powerful security monitoring system with other products. The system uses electronic fence to close the monitoring area. The electronic fence has a blocking and alarm system, which is an active intrusion prevention fence. It countered the invasion attempt, repelled the invaders, delayed the invasion time, and did not threaten people's lives. Once someone intrudes, the system starts to alarm, and the monitoring system also monitors and sends the intrusion signal to the security department.