“If police and citizens are being watched, then both are more liable to do right things.”
Travis Easter, San Diego Police
Video Surveillance System (VSS), which is commonly known as Close Circuit Television (CCTV) system – enhances surveillance, visual assessment and response capabilities of any security operation. All these activities are of paramount importance for protecting people, assets, and allied systems of an organization.
In order to suitably respond to any unusual activity, VSS has become almost a necessity for all high profile premises, including but not limited to – important strategic installations, nuclear facilities, airports, banks, shopping malls, hotels and railway stations among others.
Over a period of time, VSS has progressively evolved from the old concept of CCTV to a highly advanced protective tool. The main difference between the two is that CCTV system only links camera(s) to a monitor using a transmission system; whereas VSS integrates multiple physical security components, traditionally working independently prior to the advancement of this system. For instance, in most high profile premises, Intrusion Detection System (IDS) and VSS are essentially integrated to have required deterrence. With the help of modern gadgets, VSS’s ability can further be enhanced by broadcasting its video(s) live through internet.
VSS – Components and related information
Before moving forward, it would be appropriate to go through the components and some standard terms, which are closely related to VSS:
Cameras – Cameras convert optical view provided by the lens to an electromechanical signal for transmission. Cameras are available in different types i.e. Analogue, Digital, Megapixel, Internet Protocol (IP), Infrared (IR) and Thermal among others.
Lens – Lens provide optical view and determines the level of clarity and size of the scene. Lenses are available in different varieties i.e. wide-angle, fixed focal-length, standard, telephoto, zoom and varifocal among others. Field of View (FoV) is an angle that determines the extent of the view, and scene – it is an area that is visible in the camera. A small FoV angle provides a narrow scene, and a large FoV provides a wider scene. Lenses also determine what amount and type of image will ultimately appear on the monitor. More importantly, lens should be selected so that it provides the information according to the desired “identification” requirements. The three identification types for VSS are (1) subject (2) action (3) scene.
Transmission Medium –Transmission medium carries signals from camera and transmits them to the monitor for viewing and further recording. Main types are coaxial cable, Ethernet, twisted pair wire, network cable and fibre optic. Coaxial cable and Ethernet are the most common transmission mediums but fibre optic is the best.
Monitors – Selection of right monitor is as significant for the quality of an image as are cameras, lenses, and other components. Typically, function of monitors is to display one or more video images produced by the cameras. Various types of monitors are available these days like PC, Monochrome, CCTV, Cathode Ray Tube (CRT), Liquid Crystal Display (LCD), Organic Light-emitting Diode (LED/OLED) and Plasma.
Recording – The main purpose of recording equipment is to record the video proceedings for future use, which may be for assessment, investigation and evidence. Different types of recording equipment are available like DVR, NVR, Server/Cloud application and Managed Video System.
Before finalizing any recording system, the user must be clear what the system will be able to perform i.e. whether the system has to verify some information or has to prove something during prosecution later. This decision will lead to selection of the most appropriate type of recording system, video imaging and degree of resolution (quality).
Switchers and Multiplexers – In any typical VSS, there are more cameras than monitors and recording devices. Switchers and Multiplexers are used to route the multiple video signals to monitors and recorders which are duly designed and programmed according to the security requirements.
For example, how many frames/second you want to be displayed and recorded, motion detection, prioritizing the cameras, password protection and partitioning of video(s) for selected users.
Lighting – Lighting is another prime segment of VSS, as the quality of display produced by the cameras and lenses also depends on the nature and quality of lighting.
VSS designing – Salient principles
As applicable in any other project management process, thorough planning and systematic design is key for productive deployment of VSS. While designing VSS, following points need to be kept in mind:
The best VSS design should not stipulate any model or brand of the equipment, rather recommended system along with its spares, should be competitively available in the market (off-the-shelf).
The whole VSS should be designed in an innovative and flexible manner, so additional systems can be accommodated, if required.
VSS works as a visual tool in any security system and must be planned and applied accordingly.
Application and requirement dictates the nature of the equipment/system, and not the other way round.
It is best to design an application before establishing a budget.
Detection is not complete without an assessment. Over the period of time, it has been established that humans are poor detectors, but are good at doing assessments. So, we should use required equipment for detection, and humans for assessment of any detection.
During an alarm, quality of the VSS must produce desired images to make an accurate assessment.
If a system is obsolete but still performing well, it means application was correctly designed.
No matter what, the system will get obsolete, but that does not always mean that it is ineffective.
The expected quality of an image is determined first by the camera and lens, second by the transmission method and finally by the reproduction capability of the image storage system.
It is possible to have several video transmission methods within a single system.
Cameras from multiple/different manufacturers should not to be used in one system. This may lead to Phasing and Sequencing problems.
Step-by-Step designing of VSS
In general, security is considered as non-productive segment of any organization; and especially in this backdrop, precise application and cost-effectiveness become the prime objective of any security related project. And to achieve the above, it is obligatory to have thorough thought process behind any VSS placement.
Designing of VSS – The first and foremost step is to precisely document the purpose of whole VSS, and writing down functional/operational requirements and the overall objectives which are expected to be achieved out of the whole VSS. These objectives should be well in line with recommendations proposed in Risk Assessment of the premises. If there is any possibility of integration of different security sub-systems, that has to be made part of the design. It is very essential to spend some quality time while designing, as this will set the outcome of the whole VSS, subsequently.
Job Description (JD) of each camera – Detailed JD of each camera has to be absolutely clear in the mind of the designer. Resultantly, JD of each camera has to be defined in-detail and must be in writing. This becomes extremely vital when a VSS has to integrate with other physical security components like alarms and response. For instance, at this point, it is essential to decide about the functional requirements of each camera, like what is the target area? What activity from camera is desired? Whether to keep the cameras visible or covert? While planning JD, the desired FoV/Scene of each camera should be evaluated, checked, confirmed and documented.
Selection of each camera – Now, once the overall purpose of VSS and JD of each camera is clear, the choice for the right camera becomes much easier. While selecting, the camera gets priority over the lens. The choice of camera should be based on (1) sensitivity, (2) resolution, (3) features and (4) other design factors of cameras.
Sensitivity is the suggested light required by a camera to produce image; whether camera is required for indoor or outdoor use, availability of light in the area, and whether the light is constant or variable. If trespassing of light is an issue, IR lights may be used.
Resolution is the quality of picture produced by a camera. Analogue cameras are featured through number of horizontal lines; whereas digital cameras are measured through pixels. The desired quality dictates the type of resolution. Digital cameras are able to cover as much area as two or possibly three analogue cameras.
Features are those important functions which are to be considered while selecting the cameras.
Some of these features are:
Automatic Gain Control (AGC) is an internal video amplifying system that works to maintain the quality of video signals, when light decreases. AGC should be kept switched on, when the camera is mounted outdoors. On the other hand, AGS increases noise, which decreases video quality.
Electronic Shuttering is the ability of camera to reduce excessive light from reaching the camera imaging, without disturbing the overall performance of the camera.
Backlight Compensation (BLC) is a mechanism to view a subject which is present in front of an extremely bright background. Many ways have been established to overcome this situation, like auto iris lens, masking, and electronic iris among others.
Other design factors, which are to be considered while installing cameras:
Environment – Excessive dirt, extreme temperatures in winter and summer affect performance; moreover, some lenses tend to slowdown in cold due to the type of grease used inside the equipment.
Transportation medium – Video signals generated by the camera must be transmitted to be viewed and/or recorded. Generally, coaxial-cable is sufficient for analogue cameras, but if the distance between the camera and the control point is more than 1000 feet (304m), optical fibre may be used regardless of the type of camera. Encryption technique can secure both wire and wireless transmission against hackers and unauthorized viewers.
Selection of lens – Selection of a proper lens is one of the most crucial tasks during VSS project management, but as said earlier, it comes second after the selection of camera. Choice of lens primarily depends on the size of the scene and the amount of visual identification required. In the succeeding paragraphs, qualities and types of some very common lenses will be tabulated briefly.
Wide angle lens, as its name states, shows scene from wide angle and is suitable for short distances between 0 to 15 feet.
Standard lens is suitable for medium distances between 15 to 50 feet. This type of lens depicts scene somewhat equivalent to human eye, at the above mentioned distances.
Telephoto lens provides coverage of long distance area, but presents a narrow view. Long range is considered any distance beyond 50 feet.
Zoom lens is moveable, and adjusts varying distances according to the requirement, either by motor or manually. Motorized Zoom lens can also be programmed to track the desired object. Zoom lens can cover all the distances between wide-angle to telephoto lens.
In a single VSS, different types of lens can be used as per the requirement.
Recording or storage – VSS should be designed in a manner that it holds the necessary quantity and quality of required data. Organizations must clearly decide the purpose of the video that is to be collected. It is equally important to decide about the image resolutions, rate and the number of days of recording that has to be stored. The Confidentiality-Integrity-Availability (CIA-triad) of any information is always critical for any organization. VSS, especially internet-based, is understandably vulnerable to cyber risks, as their videos and surveillance material is viewed and stored, virtually.
Integration of VSS with other systems – Non integration of VSS with other systems is equal to wasting the precious security resources. In an ideal security system various sub-systems can be integrated e.g. VSS, access control, communication, building management, lighting and HR.
For instance, a designer may conclude that camera-1 requires automated digital video motion detection, and determines some triggers for it. After that, once a trigger is activated, only then the extra lighting will activate, and system would ask for human assessment and response will be despatched, if required. In all such cases, presence of trigger system will ease off the pressure from monitoring staff, as it is inefficient to assign people to sit and watch hundreds of scenes continuously, for hours.
Organize Maintenance – Periodic maintenance is absolutely essential for having continuous operation of VSS. Maintenance operation should be meticulously planned for complete life-cycle of the system. During initial installation, VSS should under-go the established testing methods of factory/site acceptance, and a separate contract should commence for preventive and remedial maintenance. It is one of the responsibilities of security manager to go-through the warranty clauses of the system, very carefully. Moreover, availability of critical spares at site ensures business continuity.
Periodical Audits – Periodical audits and assessments for performance of VSS should be carried out. These audits and assessments should be completed by professionals, and ideally should be conducted by someone from outside the organization. While keeping the latest situation in mind, such reports must advise any replacements or changes in the system, if required.
Video Surveillance System (VSS) has become one of the primary physical security and crime prevention measure. The two unmatchable functions of VSS are live broadcasting of the necessary desired scene for requisite response, and permanent availability of scene for investigation, evidence and other requirements.
Owing to above, it is of paramount importance that security managers should have a thorough understanding about VSS, especially once it is part of their basic function. This article provides basic information about the topic, and sets a basis to further dwell on the subject for greater insights.