network camera
A digital camera that plugs into an Ethernet network and uses standard IP protocols to transmit Motion JPEG, MPEG or H.264 video. Also called an "IP camera," the network camera was pioneered in 1996 by Axis Communications, the worldwide leader in the field.
Network cameras are typically deployed for closed-circuit TV (CCTV) surveillance. Using a dedicated network video recorder (NVR) or video management software (VMS) in a PC, video coming in from all the cameras is recorded simultaneously.
A single network camera can be used to monitor an activity in one location, and most network cameras have built-in Web servers running under Linux. The camera can be adjusted and its output viewed from any Web browser or VMS locally or remotely.
Higher Resolution and Flexibility
Since network cameras are digital, they are not confined to analog NTSC, PAL and SECAM resolutions and can thus capture video in high definition. They are also progressive scan and eliminate motion blur that occurs with interlaced analog cameras.
A system of network cameras offers the most flexibility for installing additional cameras. The target recorder, whether PC or NVR, along with all the cameras connect to the same Ethernet network, which can also support audio if needed. Adding a network camera with power-over-Ethernet (PoE) requires plugging it into the nearest PoE-enabled network switch.
In contrast, although analog cameras are still widely used, they are more cumbersome to install. Each camera must be wired directly to an electrical source as well as to a DVR specialized for CCTV or a DVR board in a PC, both of which have a fixed number of video input ports. For example, a ninth analog camera cannot be added to an eight-port DVR, requiring the purchase of additional hardware. See ONVIF, MPEG, H.264, PTZ and PIR sensor. Contrast with Webcam.
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| A Network Camera |
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| This earlier and very popular Axis camera took power from an AC outlet (black wire on right). Newer medium and high-end cameras draw their current from the Ethernet cable using power over Ethernet (PoE). A single UPS connected to the PoE switch keeps all the cameras running if the power goes out (see PoE). |