• CCTV systems provide surveillance capabilities used in the protection of people, assets, and systems. A CCTV system serves mainly as a security force multiplier, providing surveillance for a larger area, more of the time, than would be feasible with security personnel alone.

• CCTV systems are often used to support comprehensive security systems by incorporating video coverage and security alarms for barriers, intrusion detection, and access control. For example, a CCTV system can provide the means to assess an alarm generated by an intrusion detection system and record the event.

• A CCTV system links a camera to a video monitor using a direct transmission system. This differs from broadcast television where the signal is transmitted over the air and viewed with a television. New approaches within the CCTV industry are moving towards more open architecture and transmission methods versus the closed circuit, hard-wired connection systems of the past.

Architecture of CCTV System

CCTV uses components that are directly connected to generate, transmit, display, and store video data. A CCTV system can be as simple as a camera purchased from a retail electronics store connected to a video monitor. However, larger systems operated by professional security personnel are comprised of a number of components falling into several basic categories:

1. Cameras: It is an essential component of any CCTV system. Matching the right CCTV camera to a particular application is increasingly complex due to rapid technological developments and a greater range of applications. A system’s performance is affected by many factors beyond those listed in the vendor data sheets. Effective camera selection requires detailed knowledge of the camera, application, supporting architecture, and host environment.

2. Lenses: The lens on a CCTV camera is the first element in the imaging chain, which consists of the lens, camera, transmission system, image management and analysis software, and monitor. The lens focuses light or IR energy onto the imaging sensor. A lens’s role is to deliver an undistorted, evenly focused, accurate image to the imaging sensor. Systems that require superior quality images start with lenses engineered to produce a high-quality image for the imaging sensor.

3. Housings and Mounts: Selecting CCTV housing and mounting hardware is directly related to the operational system requirements, which are developed during the design and procurement phases of a CCTV installation project. In any application, the housing and mounting hardware is selected on the basis of several criteria:

   Environmental conditions, which include operating temperatures and weather conditions, such as humidity and corrosion; Architectural considerations, which are important to the aesthetics of the hardware and can affect the architectural design or change the value of the property; Installation and other special considerations that match the installed materials to the system’s intended use and planned maintenance.

4. Monitors: The function of monitors is to display video images for viewing. The selection of monitors is as important to the quality of the image as the selection of cameras, lenses, and other components in the imaging chain. The video monitor market offers a number of choices, such as liquid crystal displays (LCDs) and LED displays, various sizes, and other features. The requirements of the system will determine the type of monitor for each application.

5. Switcher and Multiplexer:

   • In CCTV systems that have more cameras than monitors and recording devices, switchers and multiplexers are used to route the video signal. Switchers are simpler in concept than multiplexers.

   • They can be set manually or automatically to send analog or digital video to a monitor or a recorder. Some switchers can send frames or fields from several cameras to a recorder in a sequential manner, recording a frame or field from each camera in sequence.

   • Multiplexers receive the analog video from several cameras and digitize the signal. Multiplexers can be programmed to prioritize the video from the different cameras according to rules.

   • Cameras covering alarmed areas in an integrated security system may be prioritized so that their images are shown on a monitor and all frames recorded.

   • Many multiplexers have imbedded motion detection and analysis software to support the recording or displaying of an image only when the software detects movement or some other phenomenon. Many multiplexers can be used in networks controlled by computer systems.

6. Recorder: Recording capability is essential for assessment, investigation, and evidence collection. Video recording has transformed from tape-based systems to digital hard drive systems. While some systems still use tape, the popularity of digital video has driven the demand for recorders with hard drive storage. Traditional analog CCTV systems in which video is recorded to video cassette recorders (VCR) are rare in today’s environment and have rapidly been taken over by DVRs and NVRs on IP networks.

Different Standards of CCTV System: