It is a visual surveillance technology
system designed to monitor the desired surrounding environment and its activities. In recent years, the role of CCTV has grown to unprecedented levels. Originally used to deter crime and anti-social behavior' such as minor offenses like littering, urinating in public and etc, CCTV now plays a more important role, assisting the police and security organizations in their investigations. CCTV is fast becoming an integral plan for crime control policies and social behaviour control theory in an effort to maintain ethnical public behaviour and public order. It has become an icon for security and its presence is guaranteed to generate a sense of security and welcomed by
many.
CCTV acts as deterrence rather than prevention to crime. CCTV deters 'opportunistic' crime, where people take advantage of a situation on the spur of the moment.
The cameras are also creating a vastly increased rate of conviction after crimes are detected.Virtually everyone caught committing an offense on camera pleads guilty nowadays. Once people know they have been videotaped, they admit the offense immediately.
The output of CCTV cameras is composite video. U.S, Japan and Canada uses NTSC system whereas most Asia and European countries uses PAL system.
Choosing the correct CCTV Camera that fits your digital surveillance requirements is very important.Below is a simplified set of guidelines when choosing the correct CCTV camera for you application.
a) Location: Indoor or outdoor application
b) Requirement for day and night surveillance
c) The angle of view requirement. Wide angle coverage or a narrow field of view is
required.
d) Budget
Focal length is measured in mm. A short focal length (e.g. 3.6mm) represents a wide angle of view while a long focal length (16mm) represents a narrow angle of view.
Auto iris lenses need a driving circuit to control and operate a motor to adjust the aperture range
in accordance to varying light conditions. The driving circuit can be placed on either the camera
lens or inside the camera itself.For video driver function, the control circuit is found on the camera lens. DC driver function camera has the control circuit built-in in the camera itself.Depending on the type of lens and camera you are using, you should always set it to the correct
setting in order for the auto iris function to operate correctly.
NTSC stands for National Television Standards Committee. It is the colour video signal television standard: 525 lines, 60Hz PAL stands for Phase Alternate Line. It is the colour video signal television standard: 625 lines,
50Hz
There are a number of VMS products out there each with different features and methods of use. The main job of any Video Management Software is to record the video from many IP cameras on the network. It is very important to select software that’s reliable and doesn’t crash; the loss of important images can be more than just embarrassing.
It’s important to use a dedicated computer system to run the software, ideally a ‘server’ which has a higher capacity and faster hard drives, processors, more RAM and better networking capabilities.
You may well have to add a network switch if you don’t have any empty ports on your current switch, or if you don’t have a network switch installed. One port is required for each camera, ideally one that includes PoE on all ports.
No, the LAN network switch operates as the switch allowing hundreds of cameras to be viewed on a network.
Via broadcasting in 2.4GHz and 5.8GHz ranges. Transmitters send the data out over wireless signals which are then picked up by receivers.
Absolutely. By using repeaters, a wireless signal can be boosted down a series of repeaters. However, video quality is like to drop the more repeaters you use. Obviously, the more distance also means more room for things to get in the way of the signal.