CCTV Overview
What Is CCTV?
Closed Circuit Television, also known by the acronym CCTV, is a private or closed video system where viewing of the video is restricted to a specific group of individuals. Systems can range in size from being within a single building, to a complex of buildings, to large campuses and city centers, and can even span across a continent. Such monitoring of areas and/or activities may be used for security, safety, industrial, or private purposes. The visual images created by a CCTV system may be viewed while an event is happening or recorded for ‘after-the-fact’ review either on-site or off-site. Review is done via the use of VHS videotapes, CD, DVD, and/or other such tape or computer based mediums. Such reviews of prerecorded visual information may also be done ‘remotely’ through the use of telephone lines, fiber optics, microwave, the internet, and/or a host of other such transmission methods according to the design and complexity of the CCTV system.
CCTV is a visual surveillance technology designed for monitoring a variety of environments and activities all at the same time. CCTV systems typically involve a dedicated communications link between cameras in the field and monitors at one or more control centers. Systems can be made up of technically mature analog cameras and image storage devices, or newly developed digital cameras and image storage devices, or a mix of the two technologies.
CCTV systems may provide real-time, time-lapse, event, or digitally recorded surveillance information to help in detecting, responding to, investigating and providing evidence for security, safety and related incidents. A CCTV system may also be used to prevent security breaches by allowing security personnel to monitor access control systems at entry points to secure areas.
A CCTV system usually involves a linked system of cameras able to be viewed and operated from a series of control rooms and/or a central point of operation. Cameras come in many configurations, but can be classified under two general categories; stationary and moving. Stationary cameras are pointed at a specific scene of interest, such as a hallway, and broadcast that one scene to the control site 100% of the time. Stationary cameras can be adjusted to compensate for the specific lighting conditions of that scene. Stationary cameras can be fully exposed, or contained within a large variety of enclosures designed to meet the specific requirements of that site, such as discreteness or vandal resistance.
Moving cameras, commonly called PTZ (for pan, tilt, zoom) allow a system operator to move the camera by remote control to follow an object of interest, such as a person or a car, over a large area of interest. This is typically done by use of a joystick in the control center that provides side to side (pan), up and down (tilt) and zoom control. PTZ devices can also be programmed to move in user-defined PTZ sequences to provide general surveillance of areas of interest. PTZ devices can be further programmed to automatically move to areas of interest, such as when a door or gate opens, or when motion is detected. Because the camera can be aimed at scenes with different lighting conditions, these cameras typically have many automated adjustments, such as auto focus and auto iris to keep the image optimized for accurate viewing.
Some systems may involve sophisticated technologies or electronic interfaces such as; night vision or low light cameras for operations at night; computer-assisted operation; interfacing with electronic alarm systems; interfacing with electronic access control systems; and much more. For example, a camera that is integrated with a motion detection system would enable alerted security staff to remotely investigate potential security incidents from a central control center as the event is happening. Other sophisticated CCTV systems incorporate technologies that make possible features such as the multiple recording of many cameras, in different locations. CCTV is also sometimes used to capture images for a facial recognition biometric system.
CCTV System Effectiveness
CCTV systems have proven to be essential tools in most any surveillance and security application. Just a partial list of applications includes banking, retail, hospital, traffic management, and city centers. In all of these applications, video cameras are used as visual tools of the security staff or security design. CCTV systems greatly increase the geographic areas that can be covered by one security professional. No longer are long, arduous guard tours needed, requiring an individual to walk or drive long distances to provide security. And once an event has transpired, video can be used for investigation and evidence in criminal and civil liability cases. The installation of CCTV security systems thus provides a large deterrence to unlawful activity, and provides a strong sense of security to patrons of facilities that use CCTV. Due to great advances in the controlling or manipulating interfacing systems, video systems can be automated to great degrees.
Advancements in ‘video motion’ detection has given the system designer the ability to use video cameras in place of fence alarms, outdoor microwave motion detection systems, outdoor modulated infrared photo beam systems, leaky coaxial motion detection systems and more with higher degrees of effectiveness and accuracy. The video motion system may be programmed to do the following: detect motion when it is moving in a specific direction; detect motion of objects of specific sizes; detect motion within three dimensional areas; etcetera. Additionally, cameras on pan/tilt systems can be designed to automatically follow or track individuals or targets throughout their visual range.
Video non-motion detection systems may be designed into a CCTV system to detect the lack of motion of objects. This allows a large, open area to be view for objects left behind. Such technology also allows guards to concentrate on other facets of security.
To protect the privacy of individuals, advanced CCTV systems are available with many features designed specifically for this need. PTZ camera systems can be programmed so that specific areas of the viewed scene are overlaid with opaque shapes to prevent viewing of non-public areas, such as into homes through their windows. In addition, control systems can be configured so that only specific security professionals can view video from specific cameras that may be viewing “sensitive” scenes.
The net result or effectiveness of any/all CCTV systems is determined by the sophistication of the interfacing modules and to the extent that the system is designed as a visual tool for the security team.
Security Surveillance Performance
In modern video systems, it is very possible to have hundreds or even thousands of cameras. Therefore, the idea that an individual or group of individuals would be able to ‘monitor’ or ‘view’ the overall system, becomes inconceivable. For this reason, modern designs try to obtain systems that are “view free” and “hands free”.
View free video is accomplished through recording “events” versus continuous recording of empty areas. Event recording is accomplished through various forms of ‘alarm interfacing’. I.e.; A magnetic switch may be added to a door to trigger the camera’s assigned recording device to record the image from the camera in the ‘event’ that the door is opened. This saves video storage room (tape, disc, or hard-drive) as well as precious time reviewing video information.
Hands free video systems are also accomplished through the use of various types of electronic, programmable triggers. I.e.; the door opened, the video recorder started recording automatically and continued until the door closed. This action frees the guard from being needed to control the function of the system versus responding to the situation.
Many systems today have the ability to be ‘pre-positioned programmed’. This gives the designer or operator the ability to set up multiple view points in advance of need. In this way, cameras on pan/tilt systems (either mechanical or digital) can be programmed to automatically move from point to point in a pre-determined route. Additionally, alarm points (such as the door in the previous paragraph) can be added to automatically move the camera’s view to the alarmed position when needed. Once again the operator is freed up to respond to versus operate the system.
CCTV System Resolution
The resolution of CCTV system is usually measured by TV lines in the field. The vertical TV lines have a maximum 350 TV lines in 525-line NTSC system and is not variable. But the horizontal TV lines, which are used as the parameter of picture quality, vary depending on the quality of camera, lens, transmission and monitor.
Camera Resolution
The industry of CCD video camera sensor uses pixels (picture elements) as its quality parameter. Medium resolution of B/W camera in EIA system is 510 horizontal pixels by 492 vertical pixels and is equivalent to 380 TV lines. High resolution is 768(H) x 492(V) pixels and equivalent to 570 TV lines. Color camera's medium resolution means 330TV lines and high resolution needs more than 460 TV lines.
Monitor Resolution
The monitors in NTSC system have 525 vertical scanning lines regardless of their size. The horizontal 700 TV lines of B/W monitors represents medium level and more than 900 TV lines means high resolution in EIA system. The color monitor's horizontal resolution of 300 TV lines means medium quality and that of more than 450 TV lines means high resolution.To maximize the system's resolution, it is recommended to choose a monitor which has better resolution than that of the camera.
Closed Circuit Television, also known by the acronym CCTV, is a private or closed video system where viewing of the video is restricted to a specific group of individuals. Systems can range in size from being within a single building, to a complex of buildings, to large campuses and city centers, and can even span across a continent. Such monitoring of areas and/or activities may be used for security, safety, industrial, or private purposes. The visual images created by a CCTV system may be viewed while an event is happening or recorded for ‘after-the-fact’ review either on-site or off-site. Review is done via the use of VHS videotapes, CD, DVD, and/or other such tape or computer based mediums. Such reviews of prerecorded visual information may also be done ‘remotely’ through the use of telephone lines, fiber optics, microwave, the internet, and/or a host of other such transmission methods according to the design and complexity of the CCTV system.
CCTV is a visual surveillance technology designed for monitoring a variety of environments and activities all at the same time. CCTV systems typically involve a dedicated communications link between cameras in the field and monitors at one or more control centers. Systems can be made up of technically mature analog cameras and image storage devices, or newly developed digital cameras and image storage devices, or a mix of the two technologies.
CCTV systems may provide real-time, time-lapse, event, or digitally recorded surveillance information to help in detecting, responding to, investigating and providing evidence for security, safety and related incidents. A CCTV system may also be used to prevent security breaches by allowing security personnel to monitor access control systems at entry points to secure areas.
A CCTV system usually involves a linked system of cameras able to be viewed and operated from a series of control rooms and/or a central point of operation. Cameras come in many configurations, but can be classified under two general categories; stationary and moving. Stationary cameras are pointed at a specific scene of interest, such as a hallway, and broadcast that one scene to the control site 100% of the time. Stationary cameras can be adjusted to compensate for the specific lighting conditions of that scene. Stationary cameras can be fully exposed, or contained within a large variety of enclosures designed to meet the specific requirements of that site, such as discreteness or vandal resistance.
Moving cameras, commonly called PTZ (for pan, tilt, zoom) allow a system operator to move the camera by remote control to follow an object of interest, such as a person or a car, over a large area of interest. This is typically done by use of a joystick in the control center that provides side to side (pan), up and down (tilt) and zoom control. PTZ devices can also be programmed to move in user-defined PTZ sequences to provide general surveillance of areas of interest. PTZ devices can be further programmed to automatically move to areas of interest, such as when a door or gate opens, or when motion is detected. Because the camera can be aimed at scenes with different lighting conditions, these cameras typically have many automated adjustments, such as auto focus and auto iris to keep the image optimized for accurate viewing.
Some systems may involve sophisticated technologies or electronic interfaces such as; night vision or low light cameras for operations at night; computer-assisted operation; interfacing with electronic alarm systems; interfacing with electronic access control systems; and much more. For example, a camera that is integrated with a motion detection system would enable alerted security staff to remotely investigate potential security incidents from a central control center as the event is happening. Other sophisticated CCTV systems incorporate technologies that make possible features such as the multiple recording of many cameras, in different locations. CCTV is also sometimes used to capture images for a facial recognition biometric system.
CCTV System Effectiveness
CCTV systems have proven to be essential tools in most any surveillance and security application. Just a partial list of applications includes banking, retail, hospital, traffic management, and city centers. In all of these applications, video cameras are used as visual tools of the security staff or security design. CCTV systems greatly increase the geographic areas that can be covered by one security professional. No longer are long, arduous guard tours needed, requiring an individual to walk or drive long distances to provide security. And once an event has transpired, video can be used for investigation and evidence in criminal and civil liability cases. The installation of CCTV security systems thus provides a large deterrence to unlawful activity, and provides a strong sense of security to patrons of facilities that use CCTV. Due to great advances in the controlling or manipulating interfacing systems, video systems can be automated to great degrees.
Advancements in ‘video motion’ detection has given the system designer the ability to use video cameras in place of fence alarms, outdoor microwave motion detection systems, outdoor modulated infrared photo beam systems, leaky coaxial motion detection systems and more with higher degrees of effectiveness and accuracy. The video motion system may be programmed to do the following: detect motion when it is moving in a specific direction; detect motion of objects of specific sizes; detect motion within three dimensional areas; etcetera. Additionally, cameras on pan/tilt systems can be designed to automatically follow or track individuals or targets throughout their visual range.
Video non-motion detection systems may be designed into a CCTV system to detect the lack of motion of objects. This allows a large, open area to be view for objects left behind. Such technology also allows guards to concentrate on other facets of security.
To protect the privacy of individuals, advanced CCTV systems are available with many features designed specifically for this need. PTZ camera systems can be programmed so that specific areas of the viewed scene are overlaid with opaque shapes to prevent viewing of non-public areas, such as into homes through their windows. In addition, control systems can be configured so that only specific security professionals can view video from specific cameras that may be viewing “sensitive” scenes.
The net result or effectiveness of any/all CCTV systems is determined by the sophistication of the interfacing modules and to the extent that the system is designed as a visual tool for the security team.
Security Surveillance Performance
In modern video systems, it is very possible to have hundreds or even thousands of cameras. Therefore, the idea that an individual or group of individuals would be able to ‘monitor’ or ‘view’ the overall system, becomes inconceivable. For this reason, modern designs try to obtain systems that are “view free” and “hands free”.
View free video is accomplished through recording “events” versus continuous recording of empty areas. Event recording is accomplished through various forms of ‘alarm interfacing’. I.e.; A magnetic switch may be added to a door to trigger the camera’s assigned recording device to record the image from the camera in the ‘event’ that the door is opened. This saves video storage room (tape, disc, or hard-drive) as well as precious time reviewing video information.
Hands free video systems are also accomplished through the use of various types of electronic, programmable triggers. I.e.; the door opened, the video recorder started recording automatically and continued until the door closed. This action frees the guard from being needed to control the function of the system versus responding to the situation.
Many systems today have the ability to be ‘pre-positioned programmed’. This gives the designer or operator the ability to set up multiple view points in advance of need. In this way, cameras on pan/tilt systems (either mechanical or digital) can be programmed to automatically move from point to point in a pre-determined route. Additionally, alarm points (such as the door in the previous paragraph) can be added to automatically move the camera’s view to the alarmed position when needed. Once again the operator is freed up to respond to versus operate the system.
CCTV System Resolution
The resolution of CCTV system is usually measured by TV lines in the field. The vertical TV lines have a maximum 350 TV lines in 525-line NTSC system and is not variable. But the horizontal TV lines, which are used as the parameter of picture quality, vary depending on the quality of camera, lens, transmission and monitor.
Camera Resolution
The industry of CCD video camera sensor uses pixels (picture elements) as its quality parameter. Medium resolution of B/W camera in EIA system is 510 horizontal pixels by 492 vertical pixels and is equivalent to 380 TV lines. High resolution is 768(H) x 492(V) pixels and equivalent to 570 TV lines. Color camera's medium resolution means 330TV lines and high resolution needs more than 460 TV lines.
Monitor Resolution
The monitors in NTSC system have 525 vertical scanning lines regardless of their size. The horizontal 700 TV lines of B/W monitors represents medium level and more than 900 TV lines means high resolution in EIA system. The color monitor's horizontal resolution of 300 TV lines means medium quality and that of more than 450 TV lines means high resolution.To maximize the system's resolution, it is recommended to choose a monitor which has better resolution than that of the camera.