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" or "netcam" is usually applied only to those used for surveillance. The first centralized IP camera was Axis Neteye 200, released in 1996 by Axis Communications.
There are two kinds of IP cameras:
- Centralized IP cameras, which require a central network video recorder (NVR) to handle the recording, video and alarm management.
- Decentralized IP cameras, which do not require a central NVR, as the cameras have recording function built-in and can thus record directly to any standard storage media, such as SD cards, NAS (network-attached storage) or a PC/server.
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History
The first centralized IP camera was released in 1996 by Axis Communications. It was called the Axis Neteye 200 and was developed by the team of Martin Gren and Carl-Axel Alm. 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 contained video, alarm, and recording management functions, thus the camera system did not require licensed video management software to manage the recording event, or video management.
The first IP camera with onboard video content analytics (VCA) was released in 2005 by Intellio. This camera was able to detect a number of different events, such as if an object was stolen, a human crossed a line, a human entered a predefined zone, or if a car moved in the wrong direction.
IP cameras are available at resolutions from 0.3 (VGA resolution) to 29 megapixels. As in the consumer TV business, in the early 21st century, there has been a shift towards high-definition video resolutions, e.g. 720p or 1080i and 16:9 widescreen format.
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Standards
Previous generations of analog CCTV cameras use established broadcast television formats (e.g. Common Intermediate Format (CIF), NTSC, PAL, and SECAM). IP cameras may differ from one another in features and functions, video encoding (compression) schemes, available 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 Communications, Bosch and Sony, each group now has numerous members. As of January 2009, each group had released version 1.0 of their specification.
Potential advantages
IP cameras differ from previous generation analog cameras which transmitted video signals as a voltage, instead IP camera images are sent using the transmission and security features of the TCP/IP protocol, which provides numerous benefits:
- Two-way audio via a single network cable allows users to listen to and speak to the subject of the video (e.g. gas station clerk assisting a customer on how to use the pay pumps)
- The use of a Wi-Fi or wireless network.
- Distributed intelligence such as video analytics can be placed in the camera itself allowing the camera to analyze images.
- Transmission of commands for PTZ (pan, tilt, zoom) cameras via a single network.
- Secure data transmission through encryption and authentication methods such as WPA, WPA2, TKIP, AES.
- Remote accessibility which allows live video from selected cameras to be viewed from any computer, mobile smartphones and other devices (with sufficient access privileges).
- PoE Power over Ethernet to supply power through the ethernet cable and operate without a dedicated power supply.
Potential disadvantages
- Higher initial cost per camera, except where cheaper webcams are used.
- High network bandwidth requirements: A modern IP-camera using video compression require depending on compression configuration about 1-2Mbit/s per camera for typical 720p/1080p resolution at full frame rate (25/30 fps). (That shall be compared with a typical CCTV camera with resolution of 640x480 pixels, 10 frames per second (10 frame/s) and a bit depth of 24-bit (uncompressed) would require over 73 Mbit/s).
- As with a CCTV/DVR system, if the video is transmitted over the public Internet rather than a private network / intranet, the system potentially becomes open to a wider audience including hackers and hoaxers. Criminals can hack into a CCTV system to observe security measures and personnel, thereby facilitating criminal acts and rendering the surveillance counterproductive. This can be counteracted by ensuring the network and device is secured and staying informed on new security methods.
- Public internet connection video is rather complicated to set up and requires a dynamic DNS. Some producers of IP cameras have made their own software available with built-in dynamic DNS.
Source of the article : Wikipedia
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