Development of Video Surveillance Systems
1. Phase 1: Analog video surveillance technology in the 1980s or at least mid-1990s.
The analog surveillance technology uses analog cameras at the front end, coaxial cables are used as transmission cables, and optical fibers and optical transceivers are used for long-distance transmission. The monitoring center uses a matrix device to input multiple channels of analog video signals. The video signals switched from the matrix multiple channels are directly connected to the monitor or large screen. The video signals are stored on tape or video tape.
2. Phase II: Semi-digital video local surveillance system from the mid-1990s to the early 2000s.
The second-generation video surveillance system is represented by the Digital Video Recorder (DVR). The system collects and stores audio and video signals in digital form. The system can record, play back, and search the surveillance site quickly based on time and alarm events. The system can exchange data with information system through telephone line, local area network, broadband network and so on.
3. Phase 3: Digital remote video surveillance from the beginning of the 21st century to the present.
With the rapid increase of bandwidth, computer processing capacity and storage capacity, and the emergence of various practical video processing technologies, the surveillance system uses the network as the platform, identifies all the surveillance devices by IP address, and adopts TCP/IP protocol to transmit and switch images, voice and data. The system adopts an open architecture and can be seamlessly integrated with access control, alarm, voice, and patrol systems. The system has good compatibility and can form a complex surveillance network.
