Surveillance Engineering

Surveillance engineering is a system that transmits video information for monitoring through optical fibres, optical terminals, wireless bridges, etc.

The monitoring project undertakes the management, control, alarm processing, video recording, video playback and user management of all front-end equipment. Pc-side web settings for support functions. Each part of the function is performed separately by a dedicated server for its own purpose. The user gets the IP address and port number of the camera based on the user name when logging in to our main site to get the images for local monitoring.

The server side obtains the IP using a web page, the client side uses POST or GET and the server returns "OK" to the client after a successful IP submission.

PC client: Outside the monitoring centre, a PC can also be connected to the network for remote monitoring.

Wireless Bridge: (supports Android display) Wireless Bridge is used to access the wireless data network and the Internet. Through the wireless bridge, monitoring information on the IP network can be transmitted to the wireless terminal, and control commands from the wireless terminal can also be transmitted to the video surveillance management system on the IP network. How to choose a surveillance transmission device.

Usually, a standard video surveillance system consists of five major components: video acquisition system, video transmission system, video switching management system, video display system and video recording system.

Video acquisition system is mainly to complete the acquisition of the front-end image signal; video transmission control system to complete the transmission of the front-end image signal and control communications; video switching management system to complete the switching control of the image signal and resource allocation; video display system to complete the front-end image signal of the terminal device output; video recording system to complete the front-end image signal of the long delay storage and playback.

In the system engineering, good video transmission design is a very important part of the monitoring system. If the construction of a good system, the choice of cameras, lenses, monitors, video recorders are high indicators, high cage-quality, but without a good transmission system, the final image seen on the monitor will not be satisfactory. System designers and installers must be based on the actual needs of the selection of appropriate transmission methods, high-quality transmission media, special connectors and equipment, and according to professional standards for installation, in order to achieve the desired transmission effect.

The front-end cameras in the security monitoring industry have traditional analog cameras and network cameras of two kinds, but there are many media used to transmit image signals, mainly twisted-pair, optical fiber and wireless, corresponding transmission equipment are twisted-pair video transmission equipment, optical transceivers and wireless bridges. The following is a brief analysis of the performance advantages of the three most widely used transmission media for monitoring systems.

Twisted pair transmission

Twisted pair transmission can reach a maximum of 2400 metres, its cheap and easy access, anti-interference ability is also good, using PoE power supply can also reduce the amount of integrated wiring tasks. However, due to the limitations of the twisted-pair cable material itself, it is not anti-ageing and cannot be transmitted in harsher conditions, such as in the field or in chemical plants, and it can only transmit one image at a time, so it is not suitable for medium and large surveillance, while the transmission distance is also limited. Twisted pair transmission is more suitable for short and medium distance, camera points are relatively scattered not a lot or points closer but more concentrated environment of the network camera video surveillance, such as banks, hotel chains, supermarkets or university campuses, etc.

Optical fiber transmission

The use of fiber optic transmission of image signals is the best way to solve the long distance transmission. Optical fibre transmission can reach up to dozens or even more than a hundred kilometres, it is by converting the video and control signals into optical signals in the optical fibre transmission, its advantages are: long transmission distance, high rate, large bandwidth, low attenuation, the best anti-interference performance, suitable for long-distance and large video transmission, such as road intersection monitoring, etc..

The use of optical fiber transmission equipment is mainly video optical transceiver and fiber optic transceiver, video optical transceiver is mainly used in the analog camera signal transmission, it is small signal loss, noise and distortion is small, high transmission quality, suitable for long-distance transmission. At present, the monitoring optical transceiver can transmit the image, data and voice signals without relay for 100 km, followed by its strong anti-interference ability, for lightning, electromagnetic radiation it is not affected, which is coaxial cable transmission and twisted pair transmission does not have.

Wide transmission frequency band

Theoretically up to 3 billion megahertz, the communication capacity is large, very suitable for video signal transmission. A video optical transceiver can access multiple groups of analogue video signals at the same time, it is suitable for multiplexing transmission, currently monitoring optical transceivers can be achieved on a core of optical fibre while transmitting 128 channels of real-time uncompressed broadcast-grade images, and video optical transceivers can not only transmit video signals, but also transmit audio signals. The fibre optic transceiver is suitable for the signal transmission of network cameras, and it also has the advantages of long transmission distance, low loss and strong anti-interference ability of the video optical transceiver.