Video surveillance - definition, purpose, composition of the system
The video surveillance system (video surveillance, video control) is designed to organize the receipt of information about the current state of the protected object (technological process) by collecting, processing, archiving, storing, displaying and analyzing this information.
The purpose of installing a video surveillance system is usually to view places that are important to control in terms of preserving material assets (car parks, supermarket shelves, warehouses, etc.), control of penetration into an object (checkpoints, fences, doors, gates, etc.) . etc.), surveillance of the movement of objects (rail stations, offices, enterprises, etc.). Video surveillance (video surveillance, video control) in the modern world, including in Ukraine, is successfully used to monitor and control technological processes in production, in the service sector.
In our practice, for the selection of equipment for video surveillance, the following conditional criteria for the quality of a video surveillance system have historically developed:
• recognition of a familiar person - since a familiar person or object can be recognized by many indirect signs (walking, type of clothing, shape of an object), inexpensive HD cameras and inexpensive processing devices - DVR are used;
• recognition of a stranger - to identify a stranger or an object, more video information is needed, therefore, HD video cameras with a resolution of 1.3-2MP or IP cameras are used, and HD DVR or NVR (IP video recorders) are used as processing devices;
• reading a car number - by the term "reading a car number" we mean the recognition of symbols and alphanumeric characters, as well as obtaining very detailed video information about the object - in this case, it is advisable to use IP video cameras with a resolution of 3MP or more, and as systems processing and recording video information IP video recorders (NVR) or video servers with intelligent PC-based software.
An important point in building a video surveillance system is to accurately determine the goals of its installation and the tasks that the video surveillance system should solve, after which it is much easier for the customer and the designer to determine the quality criteria and select equipment for the video surveillance system. Naturally, when calculating a video surveillance system, a technical inspection of the facility and drafting a project are necessary. Thanks to our experience and the use of modern methods of calculation and modeling, in most cases we make a preliminary estimate and select equipment before surveying the facility, and, as a rule, these calculations do not require significant adjustments after the inspection of the facility by a specialist.
Modern video surveillance systems, as a rule, are no longer quite CCTV - (closed circuit television - a closed circuit television system), that is, they have long become not "closed", but, on the contrary, tend to the outside world through data exchange via the Internet and allow not only to observe the object and record the received information, and recently they can process it using pattern recognition algorithms and automatically influence the object management systems on their own.
New video surveillance systems are built using IP cameras and digital processing systems (NVR) and / or servers and related software. As devices for viewing video information, you can use smartphones and tablets, laptops, traditional computers, and cloud technologies are also widely used.
For a smooth transition from outdated video surveillance systems using analog cameras, HD video surveillance technologies (HD TVI or Turbo HD, HDCVI, AHD) are used, which can significantly increase the quality of the video system over existing communications (coaxial cable) (go from 0.3MP to 2-8MP ).
Quite often, a new video surveillance system is built using HD cameras and HD DVR - in many cases it is somewhat cheaper than a fully digital system based on IP technology.
The equipment of the video surveillance system, regardless of the type of system (analogue, hybrid or digital), consists of video cameras (ensuring the collection of video information), processing and recording devices - DVR, NVR, video capture boards, a server with application software, archiving equipment and video information display devices (monitor).
A video camera is a device that generates a video signal from a light flux passing through its lens and falling on a CCD matrix. Recently, color video cameras with the ability to switch to black-and-white mode (day-night) have been used.
According to the design of the video camera can be divided into:
• Mini video cameras: modular, square, barrel, custom.
• Case (standard, professional) video cameras.
• Dome cameras.
• Video cameras like "Speed Dome".
• Mini video cameras: modular, square, barrel, custom.
Processing and recording devices - video recorders (DVR, NVR), video cards capture, video servers - allow you to process video information streams received from several video cameras, analyze video streams, record them and output them in a specified format to a monitor and a local or global network for remote viewing. They also allow you to record (with subsequent playback) images (both directly from the camcorder and from processing devices). Modern video surveillance systems usually use ordinary hard disk drives (HDDs) for the accumulation and storage of video information, and for large amounts of information, drives combined in RAID.
Computer monitors are now used as information display devices for video surveillance systems, and video information is viewed on a computer monitor or mobile phone using an application or a web browser. Video surveillance apps for Android and iOS are especially popular.
A very important component of any video surveillance system is the signal transmission medium - the cable network and the power subsystem. When building a video surveillance system using IP technologies, the cable system is built on the principles of a local computer network (LAN) and can use a different physical medium for transmitting information - a twisted-pair copper cable, an optical cable, a wireless WiFi network, etc. A power cable can traditionally be used to power video cameras, but recently POE (power over ethernet) technologies are gaining popularity, where power and data are transmitted over a single twisted pair cable. Transmission of a video signal from an analog or HD video camera to a processing device is traditionally carried out using a coaxial cable with a characteristic impedance of 75 ohms, such as LCD-75, RG-6 or RG-59, but the most progressive is the use of a twisted-pair cable with devices for transmitting video signals over twisted couple.
Most often, the quality of the video surveillance system as a whole depends on the quality of the components and materials used in the cable network and power equipment, since the end devices - video cameras, DVR, NVR (unless, of course, noname or pseudo-brand equipment is used) have very good parameters - for example, the equipment we use well-known brands such as Hikvision and Dahua. And in fact, when transmitting a video signal over a distance, engineering tasks arise to build a high-quality video surveillance system, that is, the choice of transmission medium, competent calculation of a cable or wireless network, taking into account the ever-growing resolution of video cameras and video surveillance system processing devices, comes to the fore in the design and implementation of a video surveillance system.
The ELVIS group of companies offers a full range of services for the implementation of video surveillance systems projects. The engineers of our company will select for you the system that best suits your enterprise, and the price range and performance of the equipment we offer will satisfy the most demanding customer.
We hope that the customer, regardless of the amount of work performed, will appreciate the competence of our company, the professionalism of our employees and the individual approach.
The video surveillance system can be supplemented by an access control system.