Closed Circuit Television System. It is designed for visual monitoring and control of video image or its automatic analysis (including recognition of state numbers of vehicles and persons) using optical electronic devices and components.
CCTV – what is this system, which includes video cameras, hardware, monitors, recorders, lenses, as well as various elements for signal amplification. The main task of this system is to carry out surveillance on local, local, remote objects. The majority of trading platforms, warehouses and enterprises are equipped with a similar video surveillance system, which allows to observe the actions of employees and visitors, monitor the activities of personnel and generally ensure the normal operation of the enterprise and protection from crime. These are the main functions of the system.
Destination of the CCTV video surveillance system With this system you can:
- To control the situation at a certain object.
- Receive information right at your post in real time.
- Ensure that video and audio are captured using a digital recorder.
- Get video confirmation of the violation at the object.
- Implement the alarm function, which will be based on the work of camera motion detectors or sensors.
Perhaps now you understand that this is a CCTV. The system can be considered in more detail.
The most popular security cameras on the market are models based on CCD sensors. The largest manufacturers of such cameras are well-known brands: Samsung, LG, Panasonic, Sony. Moreover, they offer both cheap economy class cameras and expensive high-quality equipment with wide functionality and increased reliability.
According to the design characteristics of CCTV cameras can be divided into several types:
- Modular. These are housingless devices that are installed in hemispheres or housings. They are so called because they do not have their own enclosure.
- They are miniature. These cameras in small housings are usually square or cylindrical in shape, used for indoor video surveillance, but it is very rare to find models with protective housings for outdoor use.
- Dome housings. They are used indoors and are usually attached to the ceiling or other horizontal surfaces using a special bracket.
- Housed. These cameras are designed for video surveillance in all conditions and rooms. They can be used outside or in buildings regardless of their accessories. Note that if they are used outdoors, they must have special thermal housings that protect the devices from frost and water and dust ingress. All this can damage electronic components, so the housings are mandatory. Otherwise, even the enclosure chamber will not last long.
- Outdoor cameras. If any camera is installed in a thermal cover with a heated lens, it already belongs to this class. It is easy to guess that they are designed for outdoor surveillance.
- Rotary and speedy. This class includes cameras with a swivel mechanism and zoom lens. It should be noted that the potential of these cameras is greater in comparison with others, so they are often used to implement effective CCTV systems.
- Hydrostabilized video cameras. These have special video stabilization systems, so they can be used on mobile objects.
In addition, for the organization CCTV system can be used analog or digital (known as IP-camera) models. Similar division can be carried out, considering designs of the device itself. For example, cameras can be wired or wireless. The latter have a high frequency antenna as a transmitting device. It can also be a Wi-Fi interface.
Recording Devices In order to finally understand what CCTV is, you need to consider video recording devices as basic elements of the system along with cameras. These are digital video recorders that record video and audio to a hard drive or other storage device.
They all fall into three categories:
Video servers – devices that are organized on a simple computer running Linux or Windows operating system with the use of video capture card and software for processing and recording video. If we are talking about organizing security of a very large enterprise, for this purpose, specially assembled computer, which later becomes the core of the security system.
Non-computer registrars like non-PC, DVR, Stand-alone.
Specialized registrars. These are systems which may include different components designed to solve specific tasks. For example, there are recorders designed to record and store video received from CCTV cameras in subway cars. In this case, explosion-proof memory can be used.
Image processing devices
No CCTV system can be implemented without this element. The image from the camera must be transferred to one monitor. For this purpose, switchers or video switches are most often used. When it is necessary to transfer several images from different cameras to one monitor, a square is used.
A more complex device is a multiplexer. It allows to organize simultaneous display of images received from different cameras and broadcast on the monitor screen. Also with its help it is possible to form consecutive change of images from all cameras for recording purposes.
Types of lenses
We have already figured out in detail what it is – CCTV. But it is possible to put a final point after consideration of kinds of lenses. At the organisation of this system the following lenses can be used:
- Monofocal lenses with constant focal length which does not vary.
- Variofocal lenses in which the focal length can be manually adjusted.
- Transfocators. Here the focal length can be changed manually or automatically. Changing this setting allows you to zoom in or out of the image, which to some extent provides increased reliability.
Now you know that this is a CCTV, what is the purpose of this system and the basic elements that make it up. If earlier this system was a rarity, today it is implemented even in the largest retail outlets. It is a rather flexible system which can cost millions of rubles or only 5-10 thousand, but its main task is to organize video surveillance of an object. Taking into account the flexibility and variety of its components, there is no specific CCTV instruction, because for each object it will be individual, taking into account the cameras used, image processing and recording devices.