Video cameras are eveywhere. Since the terrorist attacks in the U.S. on Sept. 11, 2001, as well as the London subway bombings on July 7, 2005, governments and other organizations have been increasing their surveillance efforts with newer technology and better equipment. These technologies also are playing a role in crime deterrence and unmanned aerial vehicles (UAVs).
Video surveillance systems have languished in the analog world for decades. New technology, though, is yielding some amazing new systems. Like most other video these days, the trend is toward Internet protocol (IP), digital, wireless, often humanless monitoring with intelligent software and all the benefits these improvements offer. Today’s systems incorporate a number of new functions:
• Monochrome to color: While the move away from black and white isn’t really a new trend, it is still going on. In fact, most monitoring today is in color.
• Analog to digital: While more than 80% of all surveillance cameras are older analog devices, most new installations are digital.
• Higher resolution: With digital cameras, resolutions have increased from standard-definition (SD) TV standards to multiple video formats including the 720 and 1080 high-definition (HD) standards.
• IP cameras: Most newer HD cameras are also IP cameras, which digitize the signals, packetize them in TCP/IP, and send the results over Ethernet links.
• New compression methods: Digital cameras produce a super-high data rate for HD video. However, new video compression standards have greatly reduced not only the transmission data rate but also maximized storage capability. Motion JPEG, MPEG-4, and H.264 are the most common compression methods.
• Wireless connectivity: Most installations still use coax as the link from the camera to the monitoring stations. But some new systems use existing Ethernet local-area networks (LANs) or new CAT5/6 LANs installed for the purpose. Even fiber is used in high-end systems. For the sheer convenience and low cost, though, wireless has become the link of choice in many new systems or expansions of existing cabled systems.
• Disk storage. Video archiving has moved from VHS VCRs to hard-disk drives. DVRs and special servers store the compressed video for specific periods of time. Large systems use disk arrays with 2-Tbit drives.
• Video analytics: With HD digital video, computers or FPGAs can be used to analyze the captured scenes for intelligence. Video analytics use artificial intelligence algorithms and machine vision techniques to detect motion and recognize objects and even faces. Most experts agree that the only way to deal with the growing amount of video is to partially or completely replace humans in the analysis of captured video by using the intelligence of video analytics.
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