closed circuit television (CCTV)
To limit crime in public areas, train stations, neuralgic squares, subways and tunnels, swimming pools, stores, gas stations, banks and indoor spaces, video surveillance systemsare used, which can be fixed or mobile. These systems with fixed surveillance cameras, known as Closed Circuit Television (CCTV), are also used for traffic control purposes or for controlling access to building and apartment entrances.
Video surveillance is subject to the obligation to provide information and to data protection. Thus, corresponding systems must be made recognizable so that those affected can withdraw from the monitoring. Furthermore, the recorded photos and videos may only be published with the consent of the person concerned.
Technically, CCTV systems are island systems consisting of video cameras and video recorders or networkvideorecorders( NVR) and infrastructure. In order for the video cameras to cover a comprehensive surveillance area, they generally work with PTZ cameras, Pan, Tilt, Zoom, which can be rotated in several planes and where the image can be zoomed.
As infrastructure, CCTV system can have its own proprietary cabling or communicate through local networks. Furthermore, such a system includes video multiplexers and displays for showing the individual camera images. Corresponding concepts are implemented in High Definition Serial Digital Interface( HD-SDI), in High Definition Composite Video Interface( HDCVI) or IP-based.
IP-based surveillance systems
Modern approaches are IP-based, using IP cameras or network cameras and web cameras, video servers, video codecs, the Internet with the IP protocol for transmission, hard disks for recording and graphics programs for image processing. The cameras can be controlled and monitored from any location. The resolution of the video cameras can be VGA format, QVGA or QQVGA, but formats with other resolutions are also used; such as a format with 704 x 576 pixels. These IP-based systems have little in common with traditional CCTV technology.
CCTV and IP-based surveillance systems can be used in traffic planning, authentication, or crime prevention, such as for facial recognition or gait recognition, or for analyzing motion and behavioral characteristics. Due to the increasing number of surveillance cameras and the associated personnel costs, development tools are emerging that pre-select the video recordings for conspicuous movement patterns using intelligent video analysis, Video Content Analysis( VCA).