Monday, 17 January 2011

IP camera - Wikipedia, the free encyclopedia

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An Internet protocol camera, or IP camera, is a type of digital video camera commonly employed for surveillance, and which unlike analog closed circuit television (CCTV) cameras can send and receive data via a computer network and the Internet. Although most cameras that do this are webcams, the term "IP camera" is usually applied only to those used for surveillance.

There are two kinds of IP cameras:

Contents

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[edit] History

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The first centralized IP camera was released in 1996 by Axis Communications. It used a custom web server internal to the camera. In late 1999, the company started using embedded Linux to operate its cameras. Axis also released documentation for its low-level API called "VAPIX", which builds on the open standards of HTTP and real time streaming protocol (RTSP). This open architecture was intended to encourage third-party software manufacturers to develop compatible management and recording software.

The first decentralized IP camera was released in 1999 by Mobotix. The camera's Linux system contains video, alarm and recording management functionality, thus the camera system does not require licensed video management software to manage the recording, event and video management.

IP cameras are available at resolutions of from one to 11 Megapixels.

[edit] Standards

Analog closed circuit television uses established CCTV and broadcast television formats (e.g. Common intermediate format (CIF), NTSC, PAL, and SECAM). Generally speaking, each make of IP camera will differ in its features and functions, video encoding (compression) schemes, supported network protocols, and the API to be used by video management software.

In order to address issues of standardization of IP video surveillance, two industry groups were formed in 2008. The Open Network Video Interface Forum (ONVIF) and the Physical Security Interoperability Alliance (PSIA). While the PSIA was founded by 20 member companies including Honeywell, GE Security and Cisco, and ONVIF was founded by Axis, Bosch and Sony, each group now has numerous members. As of January 2009, each group had released version 1.0 of their specification.

[edit] Potential advantages

  • Two-way audio via a single network cable allows users to communicate with what they are seeing (e.g. gas station clerk assisting a customer on how to use the prepay pumps)
  • Higher image resolution: IP cameras have a resolution of at least 640x480 and can provide multi-megapixel resolution and HDTV image quality at 30 frames per second.
  • Flexibility: IP cameras can be moved around anywhere on an IP network (including wireless).
  • Distributed intelligence: with IP cameras, video analytics can be placed in the camera itself allowing scalability in analytics solutions.
  • Transmission of commands for PTZ (pan, tilt, zoom) cameras via a single network cable.
  • Encryption & authentication: IP cameras offer secure data transmission through encryption and authentication methods such as WEP, WPA, WPA2, TKIP, AES.
  • Remote accessibility: live video from selected cameras can be viewed from any computer, anywhere, and also from many mobile smartphones and other devices.[1]
  • Cost-advantage for larger systems. Studies show that for systems with less than 16 cameras, analog technology is cheaper, between 16 and 32 they are equal, and beyond 32 cameras, IP-based systems are more cost-effective.[2]
  • IP cameras are able to function on a wireless network. Initial configuration has to be done through a router; after the IP camera is installed it can then be used on the wireless network[3] These cameras are used in navigation purpose in defence forces.
  • PoE - Power over ethernet. Modern IP cameras have the ability to operate without an additional power supply. They can work with the PoE-protocol which gives power via the ethernet-cable

[edit] Potential disadvantages

  • Higher initial cost per camera, except where cheap webcams are used.
  • High network bandwidth requirements: a typical CCTV camera with resolution of 640x480 pixels and 10 frames per second (10 frame/s) in MJPEG mode requires about 3 Mbit/s.[4]
  • Technical barrier. Most security systems including both CCTV and IP camera systems may require a professional technician to install the system.
  • As with a CCTV/DVR system, if the video is transmitted over the public Internet rather than a private IP LAN, the system becomes open to hacking and hoaxing via internet. Criminals can hack into a CCTV system to observe security measures and personnel, thereby facilitating criminal acts and rendering the IP technology counterproductive.

[edit] See also

[edit] References

via en.wikipedia.org

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