Concerns over violent crime and civil liability lawsuits have caused schools, large corporations and small businesses to investigate avenues for securing their livelihood. Closed Circuit Television (CCTV) systems are a popular security tool to combat such problems.
CCTV is strictly a visual assessment tool. Visual Assessment means having proper identifiable or descriptive information during or after an incident. These systems should not be used independently from other security measures. CCTV cannot notify the police about break-ins, fires or criminal activities. It merely records events as they occur, and is an enhancement to existing security.
Identification goals to consider when implementing a CCTV system:
Personal Identification: ability of the viewer to personally identify something within the scene, beyond a shadow of a doubt. This does not reflect human identification, but rather, the ability to identify specific information or objects within an image.
Personal identification has two very important phases: The relationship of size and detail of an image, and the angle of view from which the scene is viewed. Without careful consideration of both aspects, your CCTV system merely records useless, unidentifiable images.
Action Identification: ability of the system to capture the events occurring in front of the camera as they actually happened. Because of the need for accuracy, using time-lapse video could cause problems.
Time lapse recording captures one picture every few seconds. For every picture captured in time, there are three to four seconds where events are not being recorded. Sometimes the unrecorded seconds in time would be necessary to positively document what happened.
Installation of surveillance cameras outside of a certain area may not produce sufficient information to indicate guilt or support an arrest for theft. Placement of the camera outside the area may help narrow the scope of suspects in a theft investigation, but the video will not necessarily identify the thief.
Scene Identification: ability for the scene to stand on its own merit. In a building with many similar hallways, equipped with surveillance cameras having similar angles of view, how can the hallways be differentiated when a CCTV monitor or tape is viewed? If an action is being recorded, how can each hallway be distinguished from the others? Scene identification is an important, but often overlooked, form of identification vital to effective video systems.
Computer graphics digitally placed on the monitor and video cannot be relied on to provide the sole method of scene identification. These graphics can aid in identifying one scene from another when both have a similar angle of view. Without being able to identify the scene on its own merit, it would be easy to argue that the graphics were added to the tape after the fact.
Steps to properly design a CCTV system:
This should be done before publishing bids or ordering equipment. Keep your system's needs and purposes in perspective.
Determine the purpose of the proposed CCTV system. If it is to monitor the back aisle of a store, little advance design preparation is necessary. If the purpose is to cover several locations in a complex or several complexes, each camera's purpose and location should be decided upon before quotes, bids or system designs are presented. CCTV systems allow security personnel to monitor several areas from a single location, enhancing existing security measures. Constant monitoring and quick to problem areas requires human participation. Cameras alone cannot respond to alarms, extinguish fires or prevent injuries.
Properly defining the purpose of each camera includes weighing the security risk of each viewed area. If a high-security area is the surveillance target, it may be worthwhile to interface the CCTV system with an alarm device such as a door contact, microwave motion detector, photo beam or video motion detector. If a low security area is the surveillance target, alarm interfacing may not be necessary. Recording the video signal as a backup should be sufficient.
Before choosing a camera, decide whether its primary duty is to watch for security breaches, safety hazards, injured personnel or vehicles. In defining each camera's purpose and location, you may find a need to employ added security measures, like alarm monitoring, patrols, locks or access control.
Define the areas to be viewed by each camera. Since cameras vary in size, light sensitivity, resolution, type and power, it is essential to determine the needs of a target area prior to selecting a camera. Several factors must be considered for each target area:
Lighting. Is the lighting in the area bright or dim? Is it constant or variable? If additional lighting is required, what type of light source will be necessary?
Environment. If the camera is indoors, does it need to be protected from customers or vandals? Should the camera housing blend with the existing area decor? When a camera is mounted outside, climate changes need to be considered. If temperatures drop, will the camera's protective housing need a heater? Although most tube cameras generate enough heat to operate in temperatures below -30° F, lenses can slow down or freeze completely in the cold. If temperatures rise above 80° F, tube cameras need cooling fans. Many newer CCD, or "chip" cameras, can operate in temperatures up to 145° F without fans. If the camera unit is in the sun, shade will be required. Glare can be a factor if the lens faces east or west.
Mounting options: Will it be mounted high or low to the ground? Is the camera accessible for easy maintenance? Will the angle of view be so steep that only the top of a person's head is visible? What will each camera be required to view and from what distance? Do not depend on the camera to view more than two objectives (one major and one minor), and the camera should not pan more than 45° to the left or right from the center of its focus. Video surveillance is often ineffective when too much is expected from a single unit or installing fewer cameras than necessary. The purpose for a surveillance video system should be remembered at all times. The higher the security risk of the viewing area, the fewer objects the camera should be required to watch. In high security locations it takes four cameras to view a 360° area. Budget constraints may force a compromise.
- Choose the proper lens for each camera. Considerations in choosing the proper lens:
- format and class of the camera
- distance from the camera to the scene
- field of view desired
- whether a color camera or black and white camera is utilized
Discuss these with the equipment installer prior to accepting bids and installation. Color has many advantages over black and white, especially if security personnel are monitoring the equipment. Color holds attention longer and aids in identification of objects and individuals.
Determine where the viewing monitor(s) will be located. The monitoring location may be impacted by the distance cable can run, the proximity to isolated areas and the potential for properly securing the room's entrances/exits.
Determine the best method for transmitting the video signal from the camera to the monitor. Cables are limited by length. As the cable distance lengthens, the signal could get worse. Other methods of transmitting a signal from the camera to the monitor are radio waves, phone lines or light waves. Each method has its pros and cons.
Layout the control area and determine what enhancements are needed. Lighting requirements will have to be considered if a surveillance system is used at night. What enhancements, such as lighting, will the surveillance cameras require?
Legal Concerns of CCTV: All legal aspects of installing a CCTV system should be considered prior to purchase and installation. Legal issues should be thoroughly discussed with an attorney prior to implementation. Two common legal concerns of a CCTV system are:
Many CCTV situations promote a false sense of security. A good example is the use of "dummy" or false cameras. This may lead an individual to believe the area is being monitored and any criminal activity will generate an immediate response. Signage might also lead to a false sense of security. Signs which convey a message the cameras are utilized for the "safety and security" of patrons can lead to potential liability problems if the public believes cameras are monitored at all times and help is on the way if they become victimized. Use of "dummy" cameras, or not monitoring real cameras due to staff shortages or restrictions can create liability. It is important to determine the exact purpose of the camera and monitoring procedures. Share that information with those who may be impacted by it, generally the employees.
Invasion of privacy. To invade a person's privacy, the boundaries of his/her privacy must first be defined. An individual may have an increased expectation of privacy based on his/her location and/or the measures they employ to ensure individual privacy. You should determine whether you might invade a person's privacy by defining the area which is perceived as private. You should then determine if you have overstepped your boundaries and obtained potentially private information and why the information was obtained. Privacy considerations fall under several defined categories:
- The type of information obtained from the CCTV systems.
- The method used to obtain the information.
- The reason the information was obtained.
- How, where, and for what length the information will be stored.
- Who will have access to the information?
It is the responsibility of business professionals and consumers to use discretion, common sense and good morals when choosing procedural rules for the application and employment of a CCTV system. To minimize potential problems, frequently consult the talents of your legal staff or attorney.
The Professional's Guide to CCTV: Application and Design of CCTV, written by Charlie Pierce, was used as a reference source for this summary.