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CLOSED OBSERVATION CIRCUIT
The difference between the CCTV and standard TV is that the standard TV transmits signals open to the public. In the CCTV case the signals are not transmitted open to the public. The CCTV uses either the wireless transmission or the wire transmission of the broadcast content, so that you can send the video from the monitor's (or monitors') control video cameras or the recording device. Most of the CCTV systems are used for the surveillance of a place, which might also include the security surveillance.
Fixed cable TV connection
Wireless Connection
It is therefore obvious that a wireless connection offers you more space flexibility, as the CCTV camera can be installed almost everywhere. Many cameras of that type must be connected to a current supply. However, some CCTV cameras are battery powered.
This system can be expanded offering the possibility of image recording using a hard disk digital recording device. This device is called recorder or DVR. There are two DVR types (Digital Video Recorders). They are either autonomous devices or hard discs that are connected to a computer system. DVR is like a typical video recording device, plus the digital images received from the CCTV camera. The amount of digital images that a DVR can record depends on various factors, such as the images recorded per second, the number of cameras, the form in which the DVR saves the compressed images and videos used (e.g. MPEG4). If you have 4 cameras that use an exposure rate of 30fps and if you use a 320 x 240 image, with each camera recording only when in move mode and if you use the MPEG4 compression, you need to be able to reach the 20 for a 25 GB hard disc to be filled up in about 80 hours.
The DVR functions are the depiction of the current situation as perceived by the CCTV system, the transformation of the audiovisual data into digital information, the recording of this information in magnetic storage media and the replay/event search from saved data. The first obvious diversifying feature compared to the typical analog recorder (video) is the fact that all above functions can be performed simultaneously, with less electronic accessories (image multiplexer replacement) and consumables (cassettes), therefore in a more reliable way. However, the real groundbreaking development has to do again with the word “information”.
The data are saved in such a way that they acquire an electronic watermark (digital signature), assuring their originality both when they are played by the recorder and when they are saved in a portable medium. Moreover, this operation requires specific software enabling only changes in parameters related to the presentation form of the information and not to the change of the information itself. These features enable the use of the saved information as a proof material in courts, based on certifications issued by particular authorities.
In other words, what all the above features offer is the creation of a real-time control centre, collecting data (messages, errors, alarms) from all subsystems of the surveillance system, depicting these data in a unified form and enabling the access to this information and the information setting and recovery from a remote equipment. The recording can be performed on a continuous basis, according to a schedule or whenever a motion is detected in a camera's image, a motion that will then activate the system notification.As a result, an integrated system is created enabling its users to take the most out of the output data and take the most appropriate decisions under the current circumstances. Naturally, the data are also accessible from any part of the network, if necessary, increasing even more the system's flexibility and availability.
Image transfer
Image transfer systems enable certified users to access the live image of one or more cameras, as well as the log files via the Internet.
Our company EXIPNA SISTIMATA, as far as the CCTV surveillance systems are concerned, cooperates with the American company General Electric.