Video Surveillance
What is it? Video Surveillance also known as Closed-Circuit Television (CCTV) consists of cameras, monitors and recording devices. Camera are installed and oversee a specific area (ground, floor, entrances, etc.). These systems monitor activity or more commonly to review recorded incidents after the fact for investigations.
How it all works. (1) Analog: The most basic difference between analog and IP camera technology is the type of cable used to transmit signals. Each analog camera requires a coaxial and dedicated power cord. An analog camera signal can be transmitted over unshielded twisted pair (UTP) cable however it requires the use of specialized devices to keep the video balanced. (2) IP: Internet protocol (IP) cameras communicate over Ethernet cable. These next generation cameras can provide far better images than the traditional analogs. In most installations, IP cameras can use one Ethernet cable for both signal and power. The overwhelming majority of new CCTV camera technology developed today is IP.
Video Analytics. These extended functionalities are offered as software upgrades, licenses or camera features to assist with facial recognition, license plate recognition, motion detection, object tracking, and many other applications.
Equipment
Fixed Cameras:
Dome: Self-contained units. The camera, lens and housing are all built together into one device. The exterior housing can be hardened and installed with specialized screws to make it theft and vandal resistant.
Box: look like a box or rectangle. Indoor use with a wall or ceiling mount. We suggest these cameras are placed in a protective housing to prevent damage. The lenses on these cameras are easy to replace.
Bullet: Long, thin, with a built-in mount. Installation is easy.
Lenses:
Fixed: Inexpensive yet fairly efficient. The downfall is that they can’t be adjusted. You’ll need to physically move the lenses.
Varifocal: Provides a range of views from a main device. Lens focal lengths are measured in millimeters. A standard varifocal lens will provide for a range of views between 2.8mm to 12mm. With a varifocal lens, you can install the camera in an ideal spot and not worry about the exact view of the area. Once installed you can fine tune the picture by adjusting the lens.
Pan-Tilt-Zoom (PTZ) Cameras: PTZ’s provide users with the ability to point the camera just about anywhere and zoom-in to get the best views. They can be programmed to run a pattern and scan a pre-defined area. PTZ’s work best when a live operator is using them for an active investigation. When set on a pattern and left unattended they often only catch part of an incident.
Telephoto (or zoom lens): These lenses are critical to zoom over long distances.
Video Management Hardware:
Digital Video Recorder (DVR): They record analog CCTV video utilizing a motherboard, hard drive, operating system, power supply. Analog cameras plug into a dedicated port on the back of the DVR. The number of camera ports are commonly offered in multiples of eight (8, 16, 32).
Network Video Recorder (NVR): An NVR is the new DVR. The big difference is that NVR’s do not have hardwired analog camera ports. Network video recorders are purpose specific PC’s designed to record IP video. The NVR is connected to a network like any other PC and IP cameras are set to send video to the NVR’s hard drive. The physical connection of the NVR and IP camera to the network made is at the switch.
Hybrid-Network Video Recorder (HNVR): Utilizing these will connect technology as well as transition analog to IP video. There is a number of hardwired analog ports like a DVR but also allow for network and IP camera connection as an NVR.
Network Switch: The switch or switching hub is simply a computing device that connects many devices together to form a network. Some switches have the ability to provide Power-over-Ethernet to cameras.
Encoder: Puts analog cameras on an IP video network. The coaxial cable is connected to the encoder in lieu of the DVR. The encoder connects to the network like any IP camera and the analog video is converted to IP.
Video Management Software (VMS):
Most CCTV technology manufacturers have developed their own versions Video Management Software. Essential VMS functions allow users to view live and recorded video, export video, control cameras, and set patterns. With the rise of IP video, many companies have created mobile app extensions of their VMS for iOS and Android. The big CCTV providers will let you download and install their software for free to try it out on a few cameras. You install it on your PC or server and program the cameras yourself. If you like it and decide to keep it, camera licensing can be purchased and installed to extend the software functionality beyond the free version.
Power Supplies:
Selecting the right power supply is critical. Without enough power, the camera will not operate, and too much will damage it right out of the box
Voltage: CCTV cameras operate on 12VDC or 24VAC. In any case, you need a power supply to step down the 120VAC provided by a typical power outlet or circuit.
Power-over-Ethernet: Deliver power to cameras via the video cable. IP cameras wire back to a switch providing power to the cameras while receiving the video signal for viewing and recording.
Plug-in: Wall transformers. They plug into a wall outlet and deliver power through terminal leads. These power supplies come in any voltage/amperage configuration.
Multi-Port: These power supplies are common. MPs have 120VAC and convert to multiple outputs for multiple cameras (in multiples of 4). Newer models have backup batteries.
