ASSI 7(10)

Chapter 1

Video’s Critical Role in the Security Plan

CONTENTS

1.1 Protection of Assets

1.1.1 Overview

1.1.2 Background

1.2 The Role of Video in Asset Protection

1.5 The Bottom Line

1.1 PROTECTION OF ASSETS

The protection of personnel and assets is a manage-ment function. Three key factors governing the planning

of an assets protection program are: (1) an adequate plan designed to prevent losses from occurring, (2) ade-quate countermeasures to limit unpreventable losses, and (3) support of the protection plan by top management.

1.1.1 Overview

Most situations today require a complete safety/security plan. The plan should contain requirements for intrusion detection, video assessment, fire detection, access control, and full two-way communication. Critical functions and locations must be monitored using wired and wireless backup communications.

The most significant driving force behind the explosion in the use of closed-circuit television (CCTV) has been the worldwide increase in theft and terrorism and the com-mensurate concern and need to protect personnel and assets. The terrorist attack on September 11, 2001, brought about a quantum jump and a complete reevaluation of the personnel and asset security requirements to safe-guard a facility. To meet this new threat, video security has taken on the lead role in protecting personnel and assets. Today every state-of-the-art security system must include video as a key component to provide the “remote eyes” for security, fire, and safety.

The fateful day of September 11, 2001, has dramatized the importance of reliable communications and remote visualization of images via remote video cameras. Many lives were saved (and lost) as a consequence of the voice, video, alarm, and fire equipment in place and in use at the time of the fateful attack on the World Trade Center in New York. The availability of operational wired and wireless two-way communication between command and control headquarters and responders (police, fire, emergency) played a crucial role in life and death. The availability (or absence) at command posts of real-time video images

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at crucial locations in the Twin Towers during the attack and evacuation contributed to the action taken by com-mand personnel during the tragedy. The use (or absence) of wireless transmission from the remote video cameras in the Twin Towers clearly had an impact on the number of survivors and casualties.

During the 1990s, video components (cameras, recorders, monitors, etc.) technology matured from the legacy analog to a digital imaging technology and became compatible with computers and now forms an essential part of the security solution. In the late 1990s, digi-tal cameras were introduced into the consumer market, thereby significantly reducing price and as a result found widespread use in the security industry. Simultaneously, powerful microprocessors, large hard disk computer mem-ory storage, and random access memory (RAM) became available from the personal computer/laptop industry, thereby providing the computing power necessary to con-trol, view, record, and play back digital CCTV cameras in the security system.

The home run came with the availability and explosive acceptance and use of the Internet (and intranet) as a new means of long distance two-way communication of voice, data, and most importantly video. For over a decade the long distance transmission of video was limited to slow telephone transmission of video images—snap-shots (slow-scan video). The use of dedicated high speed (expen-sive) land lines or expensive satellite communications was limited to government and large-clientele users. Now the Internet provides near-live (near real-time) video transmis-sion communications over an inexpensive, easily accessible worldwide transmission network.

The application and integration of video into safety and security systems has come of age as a reliable, cost-effective means for assessing and responding to terrorist attacks and other life-threatening situations. Video is an effective means for deterring crimes and protecting assets and for apprehending and prosecuting offenders.

Security personnel today have the responsibility for mul-tifaceted security and safety systems in which video often plays the key role. With today’s increasing labor costs and the need for each security officer to provide more func-tionality, video more than ever before is earning its place as a cost-effective means for improving security and safety while reducing security budgets.

Loss of assets and time due to theft is a growing can-cer on our society that eats away at the profits of every organization or business, be it government, retail, service, or manufacturing. The size of the organization makes no difference to the thief. The larger the organization, the more the theft occurs and the greater the opportunity for losses. The more valuable the product, the greater the temptation for a thief to steal it. A properly designed and applied video system can be an extremely profitable invest-ment for an institution to cut losses. The prime objective of the video system should not be the apprehension of

thieves but rather the deterrence of crime through secu-rity. A successful thief needs privacy—a video system can deny that privacy.

As a security by-product, video has emerged as an effec-tive training tool for managers and security personnel. Every installation/establishment should have a security plan in place prior to an incident. Video-based training is easy to implement using the abundance of inexpen-sive camcorders and playback equipment available and the commercial video production training video services available. The use of training videos results in standard-ized procedures and improved employee efficiency and productivity.

The public at large has accepted the use of video systems in most public facilities. Video is being applied to reduce asset losses and increase corporate profits and bottom line. Many case histories show that after the installation of video, shoplifting and employee thefts drop sharply. The number of thefts cannot be counted exactly but shrinkage can be measured. It has been shown that video is an effec-tive psychological deterrent to crime and an effective tool for criminal prosecution.

Theft is not only the unauthorized removal of valuable property but also the removal of information, such as com-puter software, CDs, magnetic tape and disks, optical disks, microfilm, and hard copy. Video surveillance systems pro-vide a means for successfully deterring such thievery and/or detecting or apprehending offenders. The use of video pre-vents the destruction of property, vandalizing buildings, defacing elevator interiors, painting graffiti on art objects and facilities, stealing computers, and demolishing furni-ture or other valuable equipment. Video offers the greatest potential benefit when integrated with other sensing sys-tems and used to view remote areas. Video provides the “eyes” for many security devices and functions such as:

(1) fire sensors: smoke detector alarms, (2) watching for presence (or absence) of personnel in an area, (3) evac-uation of personnel—determining route for evacuation, access (emergency or intruder) to determine response, respond, and monitor response. When combined with fire and smoke detectors, CCTV cameras in inaccessible areas can be used to give advance warning of a fire.

Video is the critical link in the overall security of a facility but organizations must develop a complete security plan rather than adopt piecemeal protection measures. To optimize use of video technology, the practitioner and end user must understand all of its aspects—from light sources to video monitors and recorders. The capabilities and limitations of video during daytime and nighttime operation must also be understood.

1.1.2 Background

Throughout history, humans have valued their own life and the lives of their loved ones above all else. Next

in value has been their property. Over the centuries many techniques have been developed to protect prop-erty against invaders or aggressors threatening to take or destroy it.

In the past as in the present, manufacturing, industrial, and government organizations have hired “watchmen” to protect their facilities. These private security personnel wearing uniforms and using equipment much like the police do are hired to prevent crime and bodily harm, and deter or prevent theft on the premises. The very early guard companies were Pinkerton’s and Burns. Contract protection organizations were hired to safeguard their employees and assets in emergency and personal threat situations.

A significant increase in guard use came with the start of World War II. Many guards were employed to secure indus-trial work sites manufacturing military equipment and doing classified work, and to guard government facilities. Private corporations obtained such protection through contract agencies to guard classified facilities and work.

In the early 1960s, as electronic technology advanced, alarm systems and video were introduced. Radio Corpo-ration of America (RCA), Motorola, and General Electric were the pioneering companies that began manufacturing vacuum-tube television cameras for the security industry. The use of video cameras during the 1960s and 1970s grew rapidly because of increased reliability, lower cost, and technological improvements in the tube-type camera tech-nology. In the 1980s growth continued at a more modest level with further improvements in functions and availabil-ity of other accessories for video security systems.

The most significant advance in video technology dur-ing the 1980s was the invention and introduction of the solid-state video camera. By the early 1990s the solid-state camera using the charged coupled device (CCD) image sensor was the choice for new security installations and was rapidly replacing the tube cameras. In the past, the camera—in particular, the vidicon tube sensor—was the critical component in the video system. The camera deter-mined the overall performance and quality of visual intel-ligence obtainable from the security system. The vidicon tube was the weakest link in the system and was sub-ject to degradation with age and usage. The complexity and variability of the image tube and its analog electri-cal nature made it less reliable than the other solid-state components. Performance varied considerably between different camera models and camera manufacturers, and as a function of temperature and age. By contrast, the solid-state CCD sensor and newer metal oxide semicon-ductor (MOS) and complimentary MOS (CMOS) sensor cameras have long life and are stable over all operating conditions. Another factor in the explosive use of video in security systems has been the rapid improvement in equipment capability at affordable prices. This has been the result of the widespread use of solid-state camcorders

by consumers (lower manufacturing costs), and the avail-ability of low-cost video cassette recorders (VCRs), digital video recorders (DVRs), and personal computer (PC)-based equipment.

The 1990s saw the integration of computer technology with video security technology. All components were solid state. Digital video technology needed large-scale digital memories to manipulate and store video images and the computer industry had them. To achieve satisfactory video image transmission and storage, the video signal had to be “compressed” to transmit it over the existing narrowband phone line networks. The video-computer industry already had compression for broadcast, industrial, and govern-ment requirements. The video industry needed a fast and low-cost means to transmit the video images to remote locations and the US government’s Defense Advanced Research Projects Agency (DARPA) had already devel-oped the Internet, the predecessor of the World Wide Web (WWW). The Internet (and intranet) communica-tions channels and the WWW now provide this extraordi-nary worldwide ability to transmit and receive video and audio, and communicate and control data anywhere.

1.2 THE ROLE OF VIDEO IN ASSET PROTECTION

Video provides multiple functions in the overall security plan. It provides the function of asset protection by moni-toring location of assets and activity in their location. It is used to detect unwanted entry into a facility beginning at a perimeter location and following an unauthorized per-son throughout a facility. Figure 1-1 shows a typical single site video system using either legacy analog or digital, or a combination of both technologies.

In a perimeter protection role, video is used with intrusion-detection alarm devices as well as video motion detection to alert the guard at the security console that an intrusion has occurred. If an intrusion occurs, multi-ple CCTV cameras located throughout the facility follow the intruder so that there is a proper response by guard personnel or designated employees. Management must determine whether specific guard reaction is required and what the response will be.

Video monitoring allows the guard to be more effec-tive, but it also improves security by permitting the camera scene to be transmitted to other control centers or per-sonnel. The video image can be documented with a VCR, DVR, and/or printed out on a hard copy video printer.

The video system for the multiple site application is best implemented using a combination of analog/digital or an all-digital solution (Figure 1-2).

Local site installations already using analog video cam-eras, monitors, etc. can be retained and integrated with new digital Internet Protocal (IP) cameras, local area net-works (LANs), intranets, and the Internet to facilitate remote site video monitoring. The digital transmission

FIGURE 1-1 Single site video security system

network provides two-way communications of audio and controls and excellent video image transmission to remote sites. The digital signals can be encrypted to prevent eavesdropping by unauthorized outside personnel. Using a digital signal backbone allows adding additional cam-eras to the network or changing their configuration in the system.

In the relatively short history of CCTV and video there have been great innovations in the permanent record-ing of video images. These new technologies have been brought about by the consumer demand for video cam-corders, the television broadcast industry, and government requirements for military and aerospace hardware and software. One result of these requirements was the devel-opment of the VCR and DVR. The ability to record video images provided the video security industry with a new dimension, i.e. going beyond real-time camera surveil-lance. The availability of VCR and DVR technology result-ing from the consumer market has made possible the excellent time-lapse VCRs and large storage PC-based DVR systems. These technologies provide permanent documen-tation of the video images in analog (magnetic tape) and digital (solid state and hard disk drive) storage media. The use of time-lapse recorders, computer hard disks and video printers give management the tools to present hard

evidence for criminal prosecution. This ability to provide a permanent record of evidence is of prime importance to personnel responsible for providing security.

Prior to the mid-1990s the CCTV security industry pri-marily used monochrome solid-state cameras. In the 1990s the widespread use of color camcorders in the video con-sumer market accelerated the availability of these reliable, stable, long-life cameras for the security industry. While monochrome cameras are still specified in low light level

(BL) and nighttime security applications, color is now the norm in most security applications. The increased sensitivity and resolution of color cameras and the signif-icant decrease in cost of color cameras have resulted in their widespread use. Many monochrome cameras being used for LLL applications are being augmented with active infrared (IR) illuminators. Also coming into use is a new generation of passive monochrome thermal IR imaging cameras that detect the differences in temperature of objects in the scene, compared to the scene background. These cameras operate in total darkness. There has also been an explosion in the use of covert video surveillance through the use of small, inexpensive color cameras.

The development of smaller solid-state cameras has resulted in a decrease in the size of ancillary video equip-ment. Camera lenses, dome cameras, housings, pan/tilt

SITE 2

SITE 1

ANALOG

ANALOG CAMERA(S)

CAMERA(S)

CAMERAS

SERVER

SERVER

RJ45 BNC

BNC RJ45

KEYBOARD

ROUTER

KEYBOARD

DIGITAL IP

CAMERA(S)

ROUTER

*

DOMES

· COMPRESSED DIGITAL VIDEO (MJPEG, MPEG-2, MPEG-4).

· SUFFICIENT STORAGE TO SUPPORT ALL SITES WITH SECURITY AUTHENTICATION.

RAID LEVEL 5 CONTROLLER FOR EXPANDED STORAGE CAPACITY.

INTRANET

LOCAL AREA NETWORK (LAN)

WIDE AREA NETWORK (WAN)

*

MONITORING STATION

ANALOG

CAMERA(S)

SERVER

ROUTER

RJ45 BNC

DIGITAL IP

CAMERA(S)

KEYBOARD

ALARM INPUT/

OUTPUT DEVICES

FIGURE 1-2 Multiple site system using analog/digital video

mechanisms, and brackets are smaller in size and weight resulting in lower costs and providing more aesthetic installations. The small cameras and lenses satisfy covert video applications and are easy to conceal.

The potential importance of color in surveillance appli-cations can be illustrated very clearly: turn off the color on a television monitor to make it a monochrome scene. It is obvious how much information is lost when the col-ors in the scene change to shades of gray. Objects that were easily identified in the color scene become difficult to identify in the monochrome scene. It is much easier to pick out a person with a red shirt in the color image than in a monochrome image.

The security industry has long recognized the value of color to enhance personnel and article identification in video surveillance and access control. One reason why we can identify subjects more easily in color is that we are used to seeing color, both in the real world and on our TV at home. When we see a monochrome scene we have to make an additional effort to recognize certain information (besides the actual missing colors) thereby decreasing the intelligence available. Color provides more accurate identification of personnel and objects and leads

to a higher degree of apprehension and conviction of criminals.

1.2.1 Video as Part of the Emergency and Disaster Plan

Every organization regardless of size should have an emer-gency and disaster control plan that includes video as a critical component. Depending on the organization an anti-terrorist plan should take highest priority. Part of the plan should be a procedure for succession of personnel in the event one or more members of top management are unavailable when disaster strikes. In large organiza-tions the plan should include the designation of alternate headquarters if possible, a safe document-storage facility, and remote (off-site if possible) video operations capabil-ity. The plan must provide for medical aid and assure the welfare of all employees in the organization. Using video as a source of information, there should be a method to alert employees in the event of a dangerous condition and a plan to provide for quick police and emergency response. There should be an emergency shutdown plan

and restoration procedures with designated employees act-ing as leaders. There should be CCTV cameras stationed along evacuation routes and instructions for practice tests. The evacuation plan should be prepared in advance and tested.

A logical and effective disaster control plan should do the following:

· Define emergencies and disasters that could occur as they relate to the particular organization.

· Establish an organization and specific tasks with person-nel designated to carry out the plan immediately before, during, and immediately following a disaster.

· Establish a method for utilizing the organization’s resources, in particular video, to analyze the disaster situation and bring to bear all available resources.

· Recognize a plan to change from normal operations into and out of the disaster emergency mode as soon as possible.

Video plays a very important role in any emergency, disaster and anti-terrorist plan:

· Video helps protect human life by enabling security or safety officials to see remote locations and view first hand what is happening, where it is happening, what is most critical, and what areas must be attended to first.

· Aids in minimizing personal injury by permitting “remote eyes” to get to those people who require imme-diate attention, or to send personnel to the area being hit hardest to remove them from the area, or to bring in equipment to protect them.

· Video reduces the exposure of physical assets to oncom-ing disaster, such as fire or flood, and prevents or at least assesses document removal (of assets) by intruders or any unauthorized personnel.

· Video documents the equipment and assets that were in place prior to the disaster, recording them on VCR, DVR or storage on an enterprise network to be compared to the remaining assets after the disaster has occurred. It also documents personnel and their activities before, during, and after an incident.

· Probably more so than any other part of a security sys-tem, video will aid management and the security force in minimizing any disaster or emergency. It is useful in restoring an organization to normal operation by deter-mining that no additional emergencies are in progress and that procedures and traffic flow are normal in those restored areas.

1.2.1.1 Protecting Life and Minimizing Injury

Through the intelligence gathered from the video sys-tem, security and disaster control personnel should move all personnel to places of safety and shelter. Personnel assigned to disaster control and remaining in a threatened area should be protected by using video to monitor their

safety, and the access and egress at these locations. By such monitoring, advance notice is available to provide a means of support and assistance for those persons if injured, and personnel that must be rescued or relieved.

1.2.1.2 Reducing Exposure of Physical Assets and Optimizing Loss Control

Assets should be stored or secured properly before an emer-gency so that they will be less vulnerable to theft or loss. Video is an important tool for continually monitoring safe areas during and after a disaster to ensure that the material is not removed. In an emergency or disaster, the well-documented plan will call for specific personnel to locate highly valued assets, secure them, and evacuate personnel.

1.2.1.3 Restoring Normal Operations Quickly

After an emergency situation has been brought under control, security personnel can monitor and maintain the security of assets and help determine that employees are safe and have returned to their normal work routine.

1.2.1.4 Documenting an Emergency

For purposes of: (1) future planning, (2) liability and insurance, and (3) evaluation by management and secu-rity personnel, video coverage of critical areas and oper-ations during an emergency is an excellent tool and can reduce financial losses significantly. Video recordings of assets lost or stolen or personnel injured or killed can sup-port a company’s claim that it was not negligent and that it initiated a prudent emergency and disaster plan prior to the event. Although video can provide crucial documen-tation of an event, it should be supplemented with high-resolution photographs of specific instances or events.

If perimeter fences or walls were destroyed or dam-aged in a disaster, video can help prevent and document intrusion or looting by employees, spectators, or other outsiders.

1.2.1.5 Emergency Shutdown and Restoration

In the overall disaster plan, shutting down equipment such as machinery, utilities, processes, and so on, must be considered. If furnaces, gas generators, electrical power equipment, boilers, high-pressure air or oil systems, chem-ical equipment, or rapidly rotating machinery could cause damage if left unattended they should be shut down as soon as possible. Again, video surveillance can be crucial to determine if the equipment has been shut down prop-erly, if personnel must enter the area to do so, or if it must be shut down by other means.

1.2.1.6 Testing the Plan

While a good emergency plan is essential, it should not be tested for the first time in an actual disaster situation. Deficiencies are always discovered during testing. Also, a test serves to train the personnel who will carry out the plan if necessary. Video can help evaluate the plan to identify shortcomings and show personnel what they did right and wrong. Through such peer review a practical and efficient plan can be put in place to minimize losses to the organization.

1.2.1.7 Standby Power and Communications

During any emergency or disaster, primary power and communications between locations will probably be dis-rupted. Therefore, a standby power-generation system should be provided for emergency monitoring and response. This standby power comprised of a backup gas-powered generator or an uninterruptible power supply with DC batteries to extend backup operation time will keep emergency lighting, communications, and strategic video equipment online as needed. Most installations use a power sensing device that monitors the normal supply of power at various locations. When the device senses that power has been lost, the various backup equipments auto-matically switch to the emergency power source.

A prudent security plan anticipating an emergency will include a means to power vital, audio, video, and other sen-sor equipment to ensure its operation during the event. Since emergency video and audio communications must be maintained over remote distances, alternative commu-nication pathways should be supplied in the form of either auxiliary hard-wired cable (copper wire or fiber optics) or a wireless (RF, microwave, infrared) transmission system. It is usually practical to provide a backup path to only the critical cameras, not all of them. The standby generator supply-ing power to the video, safety, and emergency equipment must be sized properly. For equipment that normally oper-ates on 120 volt AC, inverters are used to convert the low voltage from the backup DC batteries (typically 12 or 24 volts DC) to the required 120 volts AC (or 230 volts AC).

1.2.2 Security Investigations

Security investigators have used video very successfully with respect to safeguarding company assets and preventing theft, negligence, outside intrusion, and so on. By using small, low-cost, covert CCTV (hidden camera and lens), it is easy to positively identify a person or to document an event without being noticed. Better video image quality, smaller lenses and cameras, wireless video transmission, and easier installation and removal of such equipment have led to this high success. Many lenses and cameras that can be hidden in rooms, hallways, or stationary objects are

available today. Equipment to provide such surveillance is available for indoor or outdoor locations in bright sunlight or in no light (IR-illuminated or thermal cameras).

1.2.3 Safety

Closed circuit television equipment is installed not always for security reasons alone but also for safety purposes as well. Security personnel can be alerted to unsafe practices or accidents that require immediate attention. An attentive guard can use CCTV cameras distributed throughout a facility in stairwells, loading docks, around machinery, etc. to observe and immediately document any safety violations or incidents.

1.2.4 The Role of the Guard

Security guards are employed to protect plant assets and personnel. Security and corporate management are aware that guards are only one element of an organization’s complete security plan. As such, the cost to implement the guard force and its ability to protect assets and personnel are analyzed in relation to the costs and roles of other technological security solutions. In this respect video has much to contribute: increased security for relatively low capital investment and low operating cost, as compared with a guard. Guards using video can increase the security coverage or protection of a facility. Alternatively, installing new CCTV equipment enables guards to monitor remote sites, allowing guard count and security costs to be reduced significantly.

1.2.5 Employee Training and Education

Video can be used as a powerful training tool. It is used widely in education and the training of security personnel because it can demonstrate lessons and examples vividly to the trainee. In this post-9/11 era, security personnel should receive professional training by all means including real video footage. Video is an important tool for the secu-rity trainer. Example procedures of all types can be shown conveniently in a short time period, and with instructions given during the presentation. Videotaped real-life situa-tions (not simulations or performances) can demonstrate the consequences of mis-applied procedures and the ben-efits of proper planning and execution by trained and knowledgeable personnel.

Every organization can supplement live training with either professional training videos or actual scenes from their own video system, demonstrating good and poor practices as well as proper guard reaction in real cases of intrusion, unacceptable employee behavior, and so on. Such internal video systems can also be used in training

exercises: trainees may take part in videotaped simulations, which are later critiqued by their supervisor. Trainees can then observe their own actions to find ways to improve and become more effective. Finally, such internal video systems are very important tools during rehearsals or tests of an emergency or disaster plan. After the run-through, all team members can monitor their own reactions, and managers or other professionals can critique them.

1.3 SYNERGY THROUGH INTEGRATION

Video equipment is most effective when integrated with other security hardware and procedures to form a coher-ent security system. When video is combined with the other security sensors the total security system is more than the individual subsystems. Synergy obtains when video assessment is combined with intrusion and motion alarm sensors, electronic access control, fire alarms, communi-cations, and security guard personnel (Figure 1-3).

1.3.1 Integrated Functions

Functionally the integrated security system is designed as a coordinated combination of equipment, personnel, and procedures that: (a) uses each component in a way that enhances the use of every other component and (b) opti-mally achieves the system’s stated objective.

In designing a security system, each element’s poten-tial contribution to loss prevention, asset protection, or personnel safety must be considered. The security plan

must specify as a minimum: (a) where and when unusual behavior should be detected, (b) what the response should be, and (c) how it should be reported and recorded. If the intruder has violated a barrier or fence the intrusion-detection system should be able to determine that a person—not an animal, bird, insect, leaf, or other object— passed through the barrier. Video provides the most pos-itive means for establishing this information. This breech in security must then be communicated by some means to security personnel so that a reaction force has sufficient information to permit an appropriate response.

In another scenario, if material is being removed by an unauthorized person in an interior location, a video surveillance system activated by a video motion detector (VMD) alarm should alert a guard and transmit the video information to security personnel for appropriate action. In both cases a guard force would be dispatched and the event recorded on a VCR, DVR or network storage and/or printed as hard copy for guard response, documentation, and prosecution.

In summary, it is the combination of sensors, commu-nication channels, monitoring displays, documentation equipment and a guard force that provides the synergy to maximize the security function. The integration of video, intrusion-detection alarms, access control, and security guards increases the overall security asset protection and employee safety at a facility.

1.3.2 System Hardware

Since a complete video security system may be assembled from components manufactured by different companies,

FIGURE 1-3 Integrated security system

all equipment must be compatible. The video equipment should be specified by one consulting or architec-ture/engineering firm, and the system and service should be purchased, installed, and maintained through a single system integrator, dealer/installer, or general contractor. If a major supplier provides a turnkey system, including all equipment, training, and maintenance, the responsi-bility of system operation resides with one vendor, which is easier to control. Buying from one source also per-mits management to go back to one installer or general contractor if there are any problems instead of having to point fingers or negotiate for service among several vendors.

Choosing a single supplier obviously requires thorough analysis to determine that the supplier: (1) will provide a system that meets the requirements of the facility, (2) will be available for maintenance when required, and (3) will still be in business in 5 or 10 years. There are many com-panies that can supply complete video systems including cameras and housings, lenses, pan/tilt mechanisms, mul-tiplexers, time-lapse VCRs or DVRs, analog and digital networks, and other security equipment required for an integrated video system. If the end user chooses compo-nents from various manufacturers, care must be taken by the system designer and installer to be aware of the differ-ences and interface the equipment properly.

If the security plan calls for a simple system with poten-tial for later expansion the equipment should be modular and ready to accept new technology as it becomes avail-able. Many larger manufacturers of security equipment anticipate this integration and expansion requirement and design their products accordingly.

Service is a key ingredient for successful system oper-ation. If one component fails, repair or replacement must be done quickly, so that the system is not shut down. Near-continuous operation is accomplished by the direct replacement method, immediate maintenance by an in-house service organization, or quick-response ser-vice calls from the installer/contractor. Service considera-tion should be addressed during the planning and initial design stages, as they affect choice of manufacturer and service provider. Most vendors use the replacement tech-nique to maintain and service equipment. If part of the system fails, the vendor replaces the defective equipment and sends it to the factory for repair. This service policy decreases security system downtime.

The key to a successful security plan is to choose the right equipment and service company, one that is cus-tomer oriented and knowledgeable about reliable, techno-logically superior products that satisfy the customer needs.

1.4 VIDEO’S ROLE AND ITS APPLICATIONS

In its broadest sense, the purpose of CCTV in any secu-rity plan is to provide remote eyes for a security operator:

to create live-action displays from a distance. The video system should have recording means—either a VCR or a DVR, or other storage media—to maintain permanent records for training or evidence. Following are some appli-cations for which video provides an effective solution:

· When overt visual observation of a scene or activity is required from a remote location.

· An area to be observed contains hazardous material or some action that may kill or injure personnel. Such areas may have toxic chemicals, biological or radioactive mate-rial, substances with high potential for fire or explosion, or items that may emit X-ray radiation or other nuclear radiation.

· Visual observation of a scene must be covert. It is much easier to hide a small camera and lens in a target loca-tion than to station a person in the area.

· There is little activity to watch in an area, as in an intrusion-detection location or a storage room, but sig-nificant events must be recorded in the area when they occur. Integration of video with alarm sensors and a time-lapse/real-time VCR or DVR provides an extremely powerful solution.

· Many locations must be observed simultaneously by one person from a central security location.

· Tracing a person or vehicle from an entrance into a facility to a final destination. The security force can pre-dict where the person or vehicle can be interdicted.

· Often a guard or security officer must only review a scene for activity periodically. The use of video elimi-nates the need for a guard to make rounds to remote locations, which is wasteful of the guard’s time.

· When a crime has been committed, capturing the scene using the video camera and recorder to have a perma-nent record and hard copy printout of the activity and event. The proliferation of high-quality printed images from VCR/DVR equipment has clearly made the case for using video for creating permanent records.

1.4.1 Video System Solutions

The most effective way to determine that a theft has occurred, when, where, and by whom, is to use video for detection and recording. The particular event can be identified, stored, and later reproduced for display or hard copy. Personnel can be identified on monochrome or color CCTV monitors. Most security installations use color CCTV cameras that provide sufficient information to document the activity and event or identify personnel or articles. The color camera permits easier identification of personnel and objects.

If there is an emergency or disaster and security person-nel must see if personnel are in a particular area, video can provide an instantaneous assessment of personnel location and availability.

In many cases during normal operations, security per-sonnel can help ensure the safety of personnel in a facility, determine that employees or visitors have not entered the facility, or confirm that personnel have exited the facil-ity. Such functions are used for example where dangerous jobs are performed or hazardous material is handled.

The synergistic combination of audio and video infor-mation from a remote site provides for effective secu-rity. Several camera manufacturers and installers combine video and audio (one-way or duplex) using an exter-nal microphone or one installed directly in the camera. The video and audio signals are transmitted over the same coaxial, unshielded-twisted-pair (UTP), or fiber-optic cable, to the security monitoring location where the scene is viewed live and/or recorded. When there is activity in the camera area the video and audio signals are switched to the monitor and the guard sees and hears the activity in the scene and initiates a response.

1.4.2 Overt vs. Covert Video

Most video installations use both overt and covert (hid-den) CCTV cameras, with more cameras overt than covert. Overt installations are designed to deter crime and pro-vide general surveillance of remote areas such as parking lots, perimeter fence lines, warehouses, entrance lobbies, hallways, or production areas. When CCTV cameras and lenses are exposed, all managers, employees, and visitors realize that the premises are under constant video surveil-lance. When the need arises, covert installations are used to detect and observe clandestine activity. While overt video equipment is often large and not meant to be con-cealed, covert equipment is usually small and designed to be hidden in objects in the environment or behind a ceiling or wall. Overt cameras are usually installed per-manently whereas covert cameras are usually designed to be installed quickly, left in place for a few hours, days, or weeks, and then removed. Since minimizing installa-tion time is desirable when installing covert cameras, video signal transmission often is wireless rather than wired.

1.4.3 Security Surveillance Applications

snow), wind, dirt, dust, sand, salt, and smoke. The out-door systems use natural daylight and artificial lighting at night supplied either by parking lights or by a co-located infrared (IR) source. Some cameras can auto-matically switch from color operation during daylight, to monochrome when the lighting decreases below some specified level for nighttime operation.

Most video security applications use fixed, permanently installed video equipment. These systems are installed for months and years and left in place until they are super-seded by new equipment or they are no longer required. There are many cases, however, where there is a require-ment for a rapid deployment of video equipment to be used for a short period of time: days, weeks, or sometimes months, and then removed to be used again in another application. Chapter 21 describes some of these trans-portable rapid deployment video systems.

1.4.4 Safety Applications

In public, government, industrial, and other facilities, a safety, security, and personnel protection plan must guard personnel from harm caused by accident, human error, sabotage, or terrorism. Security forces are expected to monitor the conditions and activities at all locations in the facility through the use of CCTV cameras.

In a hospital room or hallway the video cameras may serve a dual function: monitoring patients while also deter-mining the status and location of employees, visitors, and others. A guard can watch entrance and exit doors, hall-ways, operating rooms, drug dispensaries, and other vital areas.

Safety personnel can use video for evacuation and to determine if all personnel have left the area and are safe. Security personnel can use video for remote traffic mon-itoring and control and to ascertain high-traffic locations and how best to control them. Video plays a critical role in public safety, as a tool for monitoring vehicular traffic on highways and city streets, in truck and bus depots, at public rail and subway facilities, airports, power plants, just to name a few.

Many video applications fall broadly into two types, indoor and outdoor. This division sets a natural boundary between equipment types: those suitable for controlled indoor environments and those suitable for harsher out-door environments. The two primary parameters are envi-ronmental factors and lighting factors. The indoor system requires artificial lighting that may or may not be aug-mented by daylight. The indoor system is subject to only mild indoor temperature and humidity variations, dirt, dust, and smoke. The outdoor system must with-stand extreme temperatures, precipitation (fog, rain, and

1.4.5 Video Access Control

As security requirements become more complex and demanding, video access control and electronic access control equipments should work synergistically with each other. For medium- to low-level access control secu-rity requirements, electronic card-reading systems are adequate after a person has first been identified at some exterior perimeter location. For higher security, personal biometric descriptors (iris scanning, fingerprint, etc.) and/or video identification are necessary.

Video surveillance is often used with electronic or video access control equipment. Video access control uses video to identify a person requesting access at a remote loca-tion, on foot or in a vehicle. A guard can compare the live image and the photo ID carried by the person on a video monitor and then either allow or deny entry. For the highest level of access control security the guard uses a system to compare the live image of the person to an image of the person retrieved from a video image database or one stored in a smart card. The two images are dis-played side by side on a split-screen monitor along with other pertinent information. The video access control sys-tem can be combined with an electronic access control system to increase security and provide a means to track all attempted entries.

There are several biometric video access control systems which can positively identify a person enrolled in the sys-tem using iris, facial, or retina identification.

1.5 THE BOTTOM LINE

The synergy of a CCTV security system implies the follow-ing functional scenario:

· An intrusion alarm sensor or VMD will detect an unau-thorized intrusion or entry or attempt to remove equip-ment from an area.

· A video camera located somewhere in the alarm area is viewing the area at the location or may be pointed manually or automatically (from the guard site) to view the alarm area.

· The information from the alarm sensor and/or camera is transmitted immediately to the security console, mon-itored by personnel, and/or recorded for permanent documentation.

· The security operator receiving the alarm information has a plan to dispatch personnel to the location or to take some other appropriate action.

· After dispatching a security person to the alarm area the guard resumes normal security duties to view the response, give additional instruction, and monitor any future event.

· After a reasonable amount of time the person dis-patched should neutralize the intrusion or other event. The security guard resumes monitoring that situation to bring it to a successful conclusion and continues moni-toring the facility.

The use of video plays a crucial role in the overall secu-rity system plan. During an intrusion, disaster or theft, the video system provides information to the guard, who must make some identification of the perpetrator, assess the problem, and respond appropriately. An installation containing suitable and sufficient alarm sensors and video

cameras permits the guard to follow the progress of the event and assist the response team in countering the

attack.

The use of video and the VMD capability to track an intruder is most effective. With an intrusion alarm and visual video information, all the elements are in place for a timely, reliable transfer of information to the security officer. For maximum effectiveness, all parts of the security system must work together synergistically. If an intrusion alarm fails, the command post may not see the intruder with sufficient advance notice. If the video fails, the guard cannot identify the perpetrator or evaluate the extent of the security breech even though he may know that an intrusion has occurred. It is important that the security officer be alert and that proper audio and visual cues are provided to alert the guard when an alarm has occurred. If inadequate alarm annunciation is provided and the guard misses or misinterprets the alarm and video input, the data from either or both are not acted upon and the system fails.

In an emergency such as a terrorist attack, fire, flood, malfunctioning machinery, burst utility pipeline, etc. the operation of video, safety sensors, and human response at the console are all required. Video is an inexpensive investment for preventing accidents and minimizing dam-age when an accident occurs. Since the reaction time to a terrorist attack, fire or other disaster is critical, having various cameras at the critical locations before personnel arrive is very important. Closed circuit television cameras act as real-time eyes at the emergency location, permit-ting security and safety personnel to send the appropriate reaction force with adequate equipment to provide opti-mum response. In the case of a fire, while a sprinkler may activate or a fire sensor may produce an alarm, a CCTV camera can quickly ascertain whether the event is a false alarm, a minor alarm, or a major event. The automatic sprinkler and fire alarm system might alert the guard to the event but the video “eyes” viewing the actual scene prior to the emergency team’s dispatch often save lives and reduce asset losses.

In the case of a security violation, if a sensor detects an intrusion the guard monitoring the video cameras can determine if the intrusion requires the dispatch of per-sonnel or some other response. In the event of a major, well-planned attack on a facility by a terrorist organiza-tion or other intrusion, a diversionary tactic such as a false alarm can quickly be discovered through the use of video thereby preventing an inappropriate response.

To justify expenditures on security and safety equip-ment an organization must expect a positive return on investment. The value of assets protected must be greater than the amount spent on security, and the security sys-tem must adequately protect personnel and visitors. An effective security system reduces theft, saves money, and saves lives.

Chapter 2

Video Technology Overview

13

14 CCTV Surveillance

2.1 OVERVIEW

The second half of the 1990s has witnessed a quantum jump in video security technology. This technology has manifest with a new generation of video components, i.e. digital cameras, multiplexers, DVRs, etc. A second sig-nificant activity has been the integration of security systems with computer-based LANs, wide area networks (WANs), wireless networks (WiFi), intranets and, Internet and the World Wide Web (WWW) communications systems.

Although today’s video security system hardware is based on new technology which takes advantage of the great advances in microprocessor computing power, solid-state and magnetic memory, digital processing, and wired and wireless video signal transmission (analog, digital over the Internet, etc.), the basic video system still requires the lens, camera, transmission medium (wired cable, wireless), monitor, recorder, etc. This chapter describes current video security system components and is an introduction to their operation.

The primary function of any video security or safety system is to provide remote eyes for the security force located at a central control console or remote site. The video system includes the illumination source, the scene to be viewed, the camera lens, the camera, and the means of transmission to the remote monitoring and recording

equipment. Other equipment often necessary to complete the system include video switchers, multiplexers, VMDs, housings, scene combiners and splitters, and character generators.

This chapter describes the technology used to: (1) cap-ture the visual image, (2) convert it to a video signal,

(3) transmit the signal to a receiver at a remote location,

(4) display the image on a video monitor, and (5) record and print it for permanent record. Figure 2-1 shows the simplest video application requiring only one video cam-era and monitor.

The printer and video recorder are optional. The cam-era may be used to monitor employees, visitors, or people entering or leaving a building. The camera could be located in the lobby ceiling and pointed at the reception area, the front door, or an internal access door. The mon-itor might be located hundreds or thousands of feet away, in another building or another city or country with the security personnel viewing that same lobby, front door, or reception area. The video camera/monitor system effec-tively extends the eyes, reaching from observer location to the observed location. The basic one-camera system shown in Figure 2-1 includes the following hardware components.

· Lens. Light from the illumination source reflects off the scene. The lens collects the light from the scene

FIGURE 2-1 Single camera video system

and forms an image of the scene on the light-sensitive camera sensor.

· Camera. The camera sensor converts the visible scene formed by the lens into an electrical signal suitable for transmission to the remote monitor, recorder, and printer.

· Transmission Link. The transmission media carries the electrical video signal from the camera to the remote monitor. Hard-wired media choices include:

(a) coaxial, (b) two-wire unshielded twisted-pair (UTP),

(c) fiber-optic cable, (d) LAN, (e) WAN, (f) intranet, and (g) Internet network. Wireless choices include:

(a) radio frequency (RF), (b) microwave, or (c) optical infrared (IR). Signals can be analog or digital.

· Monitor. The video monitor or computer screens dis-play (CRT, LCD or plasma) the camera image by con-verting the electrical video signal back into a visible image on the monitor screen.

· Recorder. The camera scene is permanently recorded by a real-time or TL VCR onto a magnetic tape cassette or by a DVR using a magnetic disk hard drive.

· Hard-copy Printer. The video printer produces a hard-copy paper printout of any live or recorded video

image, using thermal, inkjet, laser, or other printing technology.

The first four components are required to make a sim-ple video system work. The recorder and/or printer is required if a permanent record is required.

Figure 2-2 shows a block diagram of a multi-camera analog video security system using these components plus additional hardware and options to expand the capability of the single-camera system to multiple cameras, monitors, recorders, etc. providing a more complex video security system.

Additional ancillary supporting equipment for more complex systems includes: camera switchers, quads, multi-plexers, environmental camera housings, camera pan/tilt mechanisms, image combiners and splitters, and scene annotators.

· Camera Switcher, Quad, Multiplexer. When a CCTV security system has multiple cameras, an electronic switcher, quad, or multiplexer is used to select differ-ent cameras automatically or manually to display the images on a single or multiple monitors, as individual or multiple scenes. The quad can digitally combine four

FIGURE 2-2 Comprehensive video security system

16 CCTV Surveillance

cameras. The multiplexer can digitally combine 4, 9, 16, and even 32 separate cameras.

· Housings. The many varieties of camera/lens housings fall into three categories: indoor, outdoor and integral camera/housing assemblies. Indoor housings protect the camera and lens from tampering and are usually constructed from lightweight materials. Outdoor hous-ings protect the camera and lens from the environment: from precipitation, extremes of heat and cold, dust, dirt, and vandalism.

· Dome Housing. The dome camera housing uses a hemispherical clear or tinted plastic dome enclosing a fixed camera or a camera with pan/tilt and zoom lens capability.

· Plug and Play Camera/Housing Combination. To sim-plify surveillance camera installations many manufac-turers are now packaging the camera-lens-housing as a complete assembly. These plug-and-play cameras are ready to mount in a wall or ceiling and to connect the power in and the video out.

· Pan/Tilt Mechanism. When a camera must view a large area, a pan and tilt mount is used to rotate it horizon-tally (panning) and to tilt it, providing a large angular coverage.

· Splitter/Combiner/Inserter. An optical or electronic image combiner or splitter is used to display more than one camera scene on a single monitor.

· Annotator. A time and date generator annotates the video scene with chronological information. A camera identifier puts a camera number (or name—FRONT DOOR, etc.) on the monitor screen to identify the scene displayed by the camera.

The digital video surveillance system includes most of the devices in the analog video system. The primary differ-ences manifest in using digital electronics and digital pro-cessing within the video devices. Digital video components use digital signal processing (DSP), digital video signal compression, digital transmission, recording and viewing. Figure 2-3 illustrates these devices and signal paths and the overall system block diagram for the digital video system.

KEYBOARD

BNC RJ45

ALTERNATE LAND LINE

SITE TO SITE CONNECTION

FIGURE 2-3 Networked digital video system block diagram

2.2 THE VIDEO SYSTEM

Figure 2-4 shows the essentials of the CCTV camera environment: illumination source, camera, lens, and the camera–lens combined field of view (FOV), that is the scene the camera–lens combination sees.

2.2.1 The Role of Light and Reflection

A scene or target area to be viewed is illuminated by nat-ural or artificial light sources. Natural sources include the sun, the moon (reflected sunlight), and starlight. Artificial sources include incandescent, sodium, metal arc, mer-cury, fluorescent, infrared, and other man-made lights. Chapter 3 describes all of these light sources in detail.

The camera lens receives the light reflected from the scene. Depending on the scene to be viewed the amount of light reflected from objects in the scene can vary from 5 or 10% to 80 or 90% of the light incident on the scene. Typical values of reflected light for normal scenes such as foliage, automobiles, personnel, and streets fall in the range from about 25–65%. Snow-covered scenes may reach 90%.

The amount of light received by the lens is a function of the brightness of the light source, the reflectivity of the scene, and the transmission characteristics of the interven-ing atmosphere. In outdoor applications there is usually a considerable optical path from the source to the scene and back to the camera; therefore the transmission through the atmosphere must be considered. When atmospheric conditions are clear, there is generally little or no atten-uation of the reflected light from the scene. However, when there is precipitation (rain, snow, or sleet, or when fog intervenes) or in dusty, smoky, or sand-blown envi-ronments, this attenuation might be substantial and must be considered. Likewise in hot climates thermal effects (heat waves) and humidity can cause severe attenuation and/or distortion of the scene. Complete attenuation of the reflected light from the scene (zero visibility) can occur, in which case no scene image is formed.

Since most solid-state cameras operate in the visible and near-infrared wavelength region the general rule of thumb with respect to visibility is that if the human eye cannot see the scene neither can the camera. Under this situa-tion, no amount of increased lighting will help; however, if the visible light can be filtered out of the scene and only the IR portion used, scene visibility might be increased

NATURAL OR ARTIFICIAL

ILLUMINATION SOURCE

SCENE VIEWED BY

CAMERA/LENS

REFLECTED LIGHT FROM SENSOR

LENS

CAMERA

LENS FIELD

OF VIEW (FOV)

SENSOR:

CCD VIDEO OUT

CMOS

INTENSIFIER

THERMAL IR POWER IN

FIGURE 2-4 Video camera, scene, and source illumination

18 CCTV Surveillance

SCENE

D = DISTANCE FROM SCENE

TO LENS

V

H

HORIZONTAL VERTICAL HEIGHT (V)

WIDTH (H)

FIGURE 2-5 Video scene and sensor geometry

somewhat. This problem can often be overcome by using a thermal infrared (IR) imaging camera that works outside of the visible wavelength range. These thermal IR cameras produce a monochrome display with reduced image qual-ity and are much more expensive than the charge coupled device (CCD) or complimentary metal oxide semiconduc-tor (CMOS) cameras (see Section 2.6.4). Figure 2-5 illus-trates the relationship between the viewed scene and the scene image on the camera sensor.

The lens located on the camera forms an image of the scene and focuses it onto the sensor. Almost all video systems used in security systems have a 4-by-3 aspect ratio (4 units wide by 3 units high) for both the image sensor and the field of view. The width parameter is designated as h, and H, and the vertical as v, and V. Some cameras have a 16 units wide by 9 units high definition television (HDTV) format.

2.2.2 The Lens Function

The camera lens is analogous to the lens of the human eye (Figure 2-6) and collects the reflected radiation from the scene much like the lens of your eye or a film camera. The function of the lens is to collect reflected light from the scene and focus it into an image onto the CCTV cam-era sensor. A fraction of the light reaching the scene from the natural or artificial illumination source is reflected

toward the camera and intercepted and collected by the camera lens. As a general rule, the larger the lens diame-ter, the more light will be gathered, the brighter the image on the sensor, and the better the final image on the mon-itor. This is why larger-aperture (diameter) lenses, having a higher optical throughput, are better (and more expen-sive) than smaller-diameter lenses that collect less light. Under good lighting conditions—bright indoor light-ing, outdoors under sunlight—the large-aperture lenses are not required and there is sufficient light to form a bright image on the sensor by using small-diameter lenses.

Most video applications use a fixed-focal-length (FFL) lens. The FFL lens like the human eye lens covers a con-stant angular field of view (FOV). The FFL lens images a scene with constant fixed magnification. A large variety of CCTV camera lenses are available with different focal lengths (FLs) that provide different FOVs. Wide-angle, medium-angle, and narrow-angle (telephoto) lenses pro-duce different magnifications and FOVs. Zoom and vari-focal lenses can be adjusted to have variable FLs and FOVs.

Most CCTV lenses have an iris diaphragm (as does the human eye) to adjust the open area of the lens and change the amount of light passing through it and reach-ing the sensor. Depending on the application, manual or automatic-iris lenses are used. In an automatic-iris CCTV lens, as in a human eye lens, the iris closes automatically when the illumination is too high and opens automatically

EYE OR CAMERA SENSOR SCENE

SCENE

CAMERA SENSOR

FIELD OF VIEW

LENS

IRIS

EYE RETINA

CAMERA SENSOR

EYE FIELD OF VIEW

AT SCENE

17 mm EYE MAGNIFICATION = 1

EYE LENS FOCAL LENGTH = 17 mm (0.67")

FIGURE 2-6 Comparing the human eye to the video camera lens

when it is too low, thereby maintaining the optimum illu-mination on the sensor at all times. Figure 2-7 shows rep-resentative samples of CCTV lenses, including FFL, vari-focal, zoom, pinhole, and a large catadioptric lens for long range outdoor use (which combines both mirror and glass optical elements). Chapter 4 describes CCTV lens charac-teristics in detail.

2.2.3 The Camera Function

The lens focuses the scene onto the camera image sen-sor which acts like the retina of the eye or the film in a photographic camera. The video camera sensor and elec-tronics convert the visible image into an equivalent elec-trical signal suitable for transmission to a remote monitor. Figure 2-8 is a block diagram of a typical analog CCTV camera.

The camera converts the optical image produced by the lens into a time-varying electric signal that changes (modulates) in accordance with the light-intensity distri-bution throughout the scene. Other camera electronic circuits produce synchronizing pulses so that the time-varying video signal can later be displayed on a monitor or recorder, or printed out as hard copy on a video printer. While cameras may differ in size and shape depending on specific type and capability, the scanning process used by most cameras is essentially the same. Almost all cameras must scan the scene, point by point, as a function of time. (An exception is the image intensifier.) Solid-state CCD or CMOS color and monochrome cameras are used in

most applications. In scenes with low illumination, sensi-tive CCD cameras with infrared (IR) illuminators are used. In scenes with very low illumination and where no active illumination is permitted (i.e. covert) low-light-level (LLL) intensified CCD (ICCD) cameras are used. These cameras are complex and expensive (Chapter 19).

Figure 2-9 shows a block diagram of a the analog camera with (a) digital signal processing (DSP) and (b) the all digital internet protocol (IP) video camera.

In the early 1990s the non-broadcast, tube-type color cameras available for security applications lacked long-term stability, sensitivity, and high resolution. Color cam-eras did not find much use in security applications until solid-state color CCTV cameras became available through the development of solid-state color sensor technology and widespread use of consumer color CCD cameras used in camcorders. Color cameras have now become stan-dard in security systems and most CCTV security cameras in use today are color. Figure 2-10 shows representative CCTV cameras including monochrome and color solid-state CCD and CMOS cameras, a small single board cam-era, and a miniature remote head camera. Chapters 5, 14, 15 and 19 describe standard and LLL security CCTV cam-eras in detail.

2.2.4 The Transmission Function

Once the camera has generated an electrical video signal representing the scene image, the signal is transmitted to a remote security monitoring site via some transmission

20 CCTV Surveillance

(A) MOTORIZED ZOOM (B) CATADIOPTRIC LONG FFL (C) FLEXIBLE FIBER OPTIC

(D) WIDE FOV FFL (E) RIGID FIBER OPTIC

(F) NARROW FOV (TELEPHOTO) FFL (G) MINI-LENS (H) STRAIGHT AND RIGHT-ANGLE

PINHOLE LENSES

FIGURE 2-7 Representative video lenses

means: coaxial cable, two-wire twisted-pair, LAN, WAN, intranet, Internet, fiber optic, or wireless techniques. The choice of transmission medium depends on factors such as distance, environment, and facility layout.

If the distance between the camera and the monitor is short (10–500 feet), coaxial cable, UTP, and fiber optic or wireless is used. For longer distances (500 to several thousand feet) or where there are electrical disturbances, fiber-optic cable and UTP are preferred. For very long distances and in harsh environments (frequent lightning storms) or between separated buildings where no electri-cal grounding between buildings is in place, fiber optics is the choice. In applications where the camera and monitor are separated by roadways or where there is no right-of-

way, wireless systems using RF, microwave or optical trans-mission is used. For transmission over many miles or from city to city the only choice is the digital or Internet IP camera using compression techniques and transmitting over the Internet and WWW. Images from these Internet systems are not real-time but sometimes come close to real-time. Chapters 6 and 7 describe all of these video transmission media.

2.2.5 The Monitor Function

At the monitoring site a cathode ray tube (CRT), LCD or plasma monitor converts the video signal back into a

FIGURE 2-8 Analog CCTV camera block diagram

FIGURE 2-9 Analog camera with DSP and all digital camera block diagram

22 CCTV Surveillance

(A) INTENSIFIED CCD CAMERA (B) 1/3" FORMAT CS MOUNT (C) 1/2" FORMAT CS MOUNT

(ICCD) COLOR CAMERA MONOCHROME CAMERA

(D) MINIATURE CAMERA (E) REMOTE HEAD CAMERA (F) THERMAL

FIGURE 2-10 Representative video cameras

visual image on the monitor face via electronic circuitry similar but inverse to that in the camera. The final scene is produced by a scanning electron beam in the CRT in the video monitor. This beam activates the phosphor on the cathode-ray tube, thereby producing a representation of the original image onto the faceplate of the monitor. Alternatively the video image is displayed point by point on an LCD or plasma screen. Chapter 8 describes monitor and display technology and hardware. A permanent record of the monitor video image is made using a VCR tape or DVR hard disk magnetic recorder and a permanent hard copy is printed with a video printer.

2.2.6 The Recording Function

For decades the VCR has been used to record monochrome and color video images. The real-time and TL VCR magnetic tape systems have been a reliable and efficient means for recording security scenes.

Beginning in the mid-1990s the DVR was developed using a computer hard disk drive and digital electron-ics to provide video image recording. The availability of large memory disks (hundreds of megabytes) made these machines available for long duration security recording. Significant advantages of the DVR over the VCR are the high reliability of the disk as compared with the cassette tape, its ability to perform high speed searches (retrieval of images) anywhere on the disk, absence of image dete-rioration after many copies are made.

2.3 SCENE ILLUMINATION

A scene is illuminated by either natural or artificial illumi-nation. Monochrome cameras can operate with any type of light source. Color cameras need light that contains all the colors in the visible spectrum and light with a rea-sonable balance of all the colors to produce a satisfactory color image.

2.3.1 Natural Light

During daytime the amount of illumination and spectral distribution of light (color) reaching a scene depends on the time of day and atmospheric conditions. The color spectrum of the light reaching the scene is important if color CCTV is being used. Direct sunlight produces the highest-contrast scene, allowing maximum identification of objects. On a cloudy or overcast day, less light is received by the objects in the scene resulting in less contrast. To produce an optimum camera picture under the wide vari-ation in light levels (daytime to nighttime), an automatic-iris camera system is required. Table 2-1 shows the light levels for outdoor illumination under bright sun, partial clouds, and overcast day down to overcast night.

Scene illumination is measured in foot candles (Fc) and can vary over a range of 10,000 to 1 (or more). This exceeds the dynamic operating range of most camera sen-sors for producing a good-quality video image. After the sun has gone below the horizon and if the moon is over-head, reflected sunlight from the moon illuminates the

NOTE: 1 lux = .093 FtCd

Table 2-1 Light Levels under Daytime and Nighttime Conditions

scene and may be detected by a sensitive monochrome camera. Detection of information in a scene under this condition requires a very sensitive camera since there is very little light reflected into the camera lens from the scene. As an extreme, when the moon is not overhead or is obscured by cloud cover, the only light received is ambient light from: (1) local man-made lighting sources,

(2) night-glow caused by distant ground lighting reflecting off particulate (pollution), clouds, and aerosols in the lower atmosphere, and (3) direct light caused by starlight. This is the most severe lighting condition and requires either: (1) ICCD, (2) monochrome camera with IR LED illumination, or (3) thermal IR camera. Table 2-2 summa-rizes the light levels occurring under daylight and these LLL conditions and the operating ranges of typical cam-eras. The equivalent metric measure of light level (lux) compared with the foot candle (Fc) is given. One Fc is equivalent to approximately 9.3 lux.

2.3.2 Artificial Light

Artificial illumination is often used to augment outdoor lighting to obtain adequate video surveillance at night. The light sources used are: tungsten, tungsten-halogen, metal-arc, mercury, sodium, xenon, IR lamps, and light emitting diode (LED) IR arrays. Figure 2-11 illustrates sev-eral examples of these lamps.

The type of lighting chosen depends on architectural requirements and the specific application. Often a partic-ular lighting design is used for safety reasons so that per-sonnel at the scene can see better, as well as for improving the video picture. Tungsten and tungsten halogen lamps have by far the most balanced color and are best for color cameras. The most efficient visual outdoor light types are

the low- and high-pressure sodium-vapor lamps to which the human eye is most sensitive. These lamps, however, do not produce all colors (missing blue and green) and therefore are not good light sources for color cameras. Metal-arc lamps have excellent color rendition. Mercury arc lamps provide good security illumination but are miss-ing the color red and therefore are not as good as the metal-arc lamps at producing excellent-quality color video images. Long-arc xenon lamps having excellent color ren-dition are often used in outdoor sports arenas and large parking areas.

Light emitting diode IR illumination arrays either mounted in monochrome video cameras or located near the camera are used to illuminate scenes when sufficient lighting is not available. Since they only emit energy in the IR spectrum they can only be used with monochrome cameras. They are used at short ranges (10–25 feet) with wide angle lenses (50–75 FOV) or at medium long ranges (25–200 feet) with medium to narrow FOV lenses (5–20 ).

Artificial indoor illumination is similar to outdoor illumination, with fluorescent lighting used extensively in addition to the high-pressure sodium, metal-arc and mercury lamps. Since indoor lighting has a rela-tively constant light level, automatic-iris lenses are often unnecessary. However, if the CCTV camera views a scene near an outside window or a door where additional light comes in during the day, or if the indoor lighting changes between daytime and nighttime operation, then an automatic-iris lens or electronically shuttered camera is required. The illumination level from most indoor light-ing is significantly lower by 100–1000 times than that of sunlight. Chapter 3 describes outdoor natural and artificial lighting and indoor man-made lighting systems available for video surveillance use.

· FOR REFERENCE ONLY

Table 2-2 Camera Capability under Natural Lighting Conditions

(A) TUNGSTEN HALOGEN (B) FLUORESCENT (C) HIGH PRESSURE SODIUM

• STRAIGHT

• U

(D) TUNGSTEN PAR (E) XENON LONG ARC (F) HIGH INTENSITY DISCHARGE

• SPOT METALARC

• FLOOD

NOTE: PAR = PARABOLIC ALUMINIZED REFLECTOR

FIGURE 2-11 Representative artificial light sources

2.4 SCENE CHARACTERISTICS

The quality of the video image depends on various scene characteristics that include: (1) the scene lighting level,

(2) the sharpness and contrast of objects relative to the scene background, (3) whether objects are in a simple, uncluttered background or in a complicated scene, and

(4) whether objects are stationary or in motion. These scene factors will determine whether the system will be able to detect, determine orientation, recognize, or iden-tify objects and personnel. As will be seen later the scene illumination—via sunlight, moonlight, or artificial sources—and the actual scene contrast play important roles in the type of lens and camera necessary to produce a quality image on the monitor.

2.4.1 Target Size

In addition to the scene’s illumination level and the object’s contrast with respect to the scene background, the object’s apparent size—that is, its angular FOV as seen by the camera—influences a person’s ability to detect it. (Try to find a football referee with a striped shirt in a field of zebras.)

The requirements of a video system are a function of the application. These include: (1) detection of the object or movement in the scene; (2) determination of the object’s orientation; (3) recognition of the type of object in the scene, that is, adult or child, car or truck; or (4) identi-fication of the object (Who is the person? Exactly what kind of truck is it?). Making these distinctions depends on the system’s resolution, contrast, and signal-to-noise ratio (S/N). In a typical scene the average observer can detect a target about one-tenth of a degree in angle. This can be related to a standard video picture that has 525 horizon-tal lines (NTSC) and about 350 TV line vertical and 500 TV line horizontal resolution. Figure 2-12 and Table 2-3 summarize the number of lines required to detect, ori-ent, recognize, or identify an object in a television pic-ture. The number of TV lines required will increase for conditions of poor lighting, highly complex backgrounds, reduced contrast, or fast movement of the camera or target.

2.4.2 Reflectivity

The reflectivity of different materials varies greatly depend-ing on its composition and surface texture. Table 2-4 gives

FIGURE 2-12 Object size vs. intelligence obtained

· ONE TV LINE CORRESPONDS TO A LIGHT AND DARK LINE (ONE TV LINE PAIR)

as averaged over the entire visible spectrum from blue to red, the color camera can distinguish between green and red.

It is easier to identify a scene characteristic by a differ-ence in color in a color scene than it is to identify it by a difference in gray scale (intensity) in a monochrome scene. For this reason the target size required to make an identification in a color scene is generally less than it is to make the same identification in a monochrome scene.

Table 2-3 TV Lines vs. Intelligence Obtained

some examples of materials and objects viewed by video cameras and their respective reflectivities.

Since the camera responds to the amount of light reflected from the scene it is important to recognize that objects have a large range of reflectivities. The objects with the highest reflectivities produce the brightest images. To detect one object located within the area of another the objects must differ in reflectivity, color, or texture. There-fore, if a red box is in front of a green wall and both have the same reflectivity and texture, the box will not be seen on a monochrome video system. In this case, the total reflectivity in the visible spectrum is the same for the green wall and the red box. This is where the color camera shows its advantage over the monochrome camera.

The case of a color scene is more complex. While the reflectivity of the red box and the green wall may be the same

2.4.3 Effects of Motion

A moving object in a video image is easier to detect, but more difficult to recognize than a stationary one pro-vided that the camera can respond to it. Low light level cameras produce sharp images for stationary scenes but smeared images for moving targets. This is caused by a phenomenon called “lag” or “smear.” Solid-state sensors (CCD, CMOS, and ICCD) do not exhibit smear or lag at normal light levels and can therefore produce sharp images of both stationary and moving scenes. Some image intensifiers exhibit smear when the scene moves fast or when there is a bright light in the FOV of the lens.

When the target in the scene moves very fast the inher-ent camera scan rate (30 frames per second) causes a blurred image of this moving target in the camera. This is analogous to the blurred image in a still photograph when the shutter speed is too slow for the action. There is no cure for this as long as the standard NTSC (National Tele-vision System Committee) television scan rate (30 frames per second) is used. However, CCTV snapshots can be

· VISIBLE SPECTRUM: 400–700 NANOMETERS

Table 2-4 Reflectivity of Common Materials

taken without any blurring using fast-shuttered CCD cam-eras. For special applications in which fast-moving targets must be imaged and tracked, higher scan rate cameras are available.

2.4.4 Scene Temperature

Scene temperature has no effect on the video image in a CCD, CMOS, or ICCD sensor. These sensors do not respond to temperature changes or temperature differences in the scene. On the other hand, IR thermal imaging cameras do respond to temperature differences and changes in temperature in the scene. Thermal imagers do not respond to visible light or the very near-IR radiation like that pro-duced by IR LEDs. The sensitivity of IR thermal imagers is defined as the smallest change in temperature in the scene that can be detected by the thermal camera.

2.5 LENSES

A lens collects reflected light from the scene and focuses it onto the camera image sensor. This is analogous to the lens of the human eye focusing a scene onto the retina at the back of the eye (Figure 2-6). As in the human eye, the camera lens inverts the scene image on the image sensor, but the eye and the camera electronics compensate (invert the image) to perceive an upright scene. The retina of the human eye differs from any CCTV lens in that it focuses a sharp image only in the central 10% of its total

160 FOV. All vision outside the central focused scene is out of focus. This central imaging part of the human eye can be characterized as a medium FL lens: 16–25 mm. In principle, Figure 2-6 represents the function of any lens in a video system.

Many different lens types are used for video surveillance and safety applications. They range from the simplest FFL manual-iris lenses to the more complex variable-focal-length (vari-focal) and zoom lenses, with an automatic iris being an option for all types.

In addition, pinhole lenses are available for covert appli-cations, split-image lenses for viewing multiple scenes on one camera, right-angle lenses for viewing a scene perpen-dicular to the camera axis, and rigid or flexible fiber-optic lenses for viewing through thick walls, under doors, etc.

2.5.1 Fixed-Focal-Length Lens

Figure 2-13 illustrates three fixed focal length (FFL) or fixed FOV lenses with narrow (telephoto), medium, and wide FOVs and the corresponding FOV obtained when used with a 1/3-inch camera sensor format.

Wide-FOV (short FL) lenses permit viewing a very large scene (wide angle) with low magnification and therefore

provide low resolution and low identification capabilities. Narrow-FOV or telephoto lenses have high magnification, with high resolution and high identification capabilities.

2.5.2 Zoom Lens

The zoom lens is more versatile and complex than the FFL lens. Its FL is variable from wide-angle to narrow-angle (telephoto) FOV (Figure 2-14).

The overall camera/lens FOV depends on the lens FL and the camera sensor size as shown in Figure 2-14. Zoom lenses consist of multiple lens groups that are moved within the lens barrel by means of an external zooming ring (manual or motorized), thereby changing the lens FL and angular FOV without having to switch lenses or refocusing. Zoom focal length ratios can range from 6 to 1 up to 50 to 1. Zoom lenses are usually large and used on pan/tilt mounts viewing over large areas and distances (25–500 feet).

2.5.3 Vari-Focal Lens

The vari-focal lens is a variable focal length lens used in applications where a FFL lens would be used. In general they are smaller and cost much less than zoom lenses. Like the zoom lens, the vari-focal lens is used because its focal length (angular FOV) can be changed manually or automatically, using a motor, by rotating the barrel on the lens. This feature makes it convenient to adjust the FOV to a precise angle when installed on the camera. Typical vari-focal lenses have focal lengths of 3–8 mm, 5–12 mm, 8–50 mm. With just these three lenses focal lengths of from 3 to 50 mm (91–5 horizontal FOV) can be covered on a 1/3-inch format sensor. Unlike zoom lenses, vari-focal lenses must be refocused each time the FL and the FOV are changed. They are not suitable for zoom or pan/tilt applications.

2.5.4 Panoramic—360 Lens

There has always been a need to see “all around,” i.e. an entire room or other location, seeing 360 with one panoramic camera and lens. In the past, 360 FOV camera viewing systems have only been achieved by using multiple cameras and lenses and combining the scenes on a split-screen monitor.

Panoramic lenses have been available for many years but have only recently been combined with digital electron-ics and sophisticated mathematical transformations to take advantage of their capabilities. Figure 2-15 shows two lenses having a 360 horizontal FOV and a 90 vertical FOV.

The panoramic lens collects light from the 360 panoramic scene and focuses it onto the camera sensor as

FIGURE 2-13 Representative FFL lenses and their fields of view (FOV)

FIGURE 2-14 Zoom video lens horizontal field of view (FOV)

(A) (B)

FIGURE 2-15 Panoramic 360 lens

a donut-shaped image. The electronics and mathematical algorithm converts this donut-shaped panoramic image into the rectangular (horizontal and vertical) format for normal monitor viewing (Section 2.6.5).

2.5.5 Covert Pinhole Lens

This special security lens is used when the lens and CCTV camera must be hidden. The front lens element or aperture is small (from 1/16 to 5/16 of an inch in diame-ter). While this is not the size of a pinhead it nevertheless

has been labeled a pinhole lens. Figure 2-16 shows exam-ples of straight and right-angle pinhole lenses used with C or CS mount cameras. The very small mini-pinhole lenses are used on the low-cost, small board cameras.

2.5.6 Special Lenses

Some special lenses useful in security applications include split-image, right-angle, relay, and fiber optic (Figure 2-17).

(A) PINHOLE LENSES (B) MINI-LENSES

FIGURE 2-16 Pinhole and mini-pinhole lenses

(A) DUAL SPLIT IMAGE LENS (B) TRI SPLIT IMAGE LENS (C) RIGHT ANGLE LENS

(D) RIGID FIBER OPTICS (E) RELAY LENS (F) FLEXIBLE FIBER OPTICS

FIGURE 2-17 Special video lenses

The dual-split and tri-split lenses use only one camera to produce multiple scenes. These are useful for viewing the same scene with different magnifications or different scenes with the same or different magnifications. Using only one camera can reduce cost and increases reliabil-ity. These lenses are useful when two or three views are required and only one camera was installed.

The right-angle lens permits a camera using a wide-angle lens installed to view a scene that is perpendicular to the camera’s optical axis. There are no restrictions on the focal lengths so they can be used in wide- or narrow-angle applications.

The flexible and rigid coherent fiber-optic lenses are used to mount a camera several inches to several feet away from the front lens as might be required to view from the opposite side of a wall or in a hazardous environment. The function of the fiber-optic bundle is to transfer the focused visual image from one location to another. This may be useful for: (1) protecting the camera, and (2) locating the lens in one environment (outdoors) and the camera in another (indoors).

2.6 CAMERAS

The camera lens focuses the visual scene image onto the camera sensor area point-by-point and the camera electronics transforms the visible image into an electrical signal. The camera video signal (containing all picture information) is made up of frequencies from 30 cycles per second, or 30 hertz (Hz), to 4.2 million cycles per second, or 4.2 megahertz (MHz). The video signal is transmitted via a cable (or wireless) to the monitor display.

Almost all security cameras in use today are color or monochrome CCD with the rapid emergence of CMOS types. These cameras are available as low-cost single printed circuit board (PCB) cameras with small lenses already built in, with or without a housing used for covert and overt surveillance applications. More expensive cam-eras in a housing are larger and more rugged and have a C or CS mechanical mount for accepting any type of lens. These cameras have higher resolution and light sen-sitivity and other electrical input/output features suitable for multiple camera CCTV systems. The CCD and CMOS

cameras with LED IR illumination arrays can extend the use of these cameras to nighttime use. For LLL appli-cations, the ICCD and IR cameras provide the highest sensitivity and detection capability.

Significant advancements in camera technology have been made in the last few years particularly in the use of digital signal processing (DSP) in the camera, and devel-opment of the IP camera. All security cameras manufac-tured between the 1950s and 1980s were the vacuum tube type, either vidicon, silicon, or LLL types using silicon intensified target (SIT) and intensified SIT (ISIT). In the 1980s the CCD and CMOS solid-state video image sensors were developed and remain the mainstay in the security industry. Increased consumer demand for video recorders using CCD sensors in camcorders and the CMOS sensor in digital still frame cameras caused a technology explosion and made these small, high resolution, high sensitivity, monochrome and color solid-state cameras available for security systems.

The security industry now has at its disposal both analog and digital surveillance cameras. Up until the mid-1990s analog cameras dominated, with only rare use of DSP elec-tronics, and the digital Internet camera was only being

introduced to the security market. Advances in solid-state circuitry, the demand from the consumer market and the availability of the Internet were responsible for the rapid use of digital cameras for security applications.

2.6.1 The Scanning Process

Two methods used in the camera and monitor video scan-ning process are raster scanning and progressive scanning. In the past, analog video systems have all used the raster scanning technique, however, newer digital systems are now using progressive scanning. All cameras use some form of scanning to generate the video picture. A block diagram of the CCTV camera and a brief description of the analog raster scanning process and video signal are shown in Figures 2-8, 2-9, 2-18, and 2-19.

The camera sensor converts the optical image from the lens into an electrical signal. The camera electronics process the video signal and generate a composite video signal containing the picture information (luminance and color) and horizontal and vertical synchronizing pulses. Signals are transmitted in what is called a frame of picture

FIGURE 2-18 Analog video scanning process and video display signal

video, made up of two fields of information. Each field is transmitted in 1/60 of a second and the entire frame in 1/30 of a second, for a repetition rate of 30 frames per second (fps). In the United States, this format is the Elec-tronic Industries Association (EIA) standard called the NTSC (National Television System Committee) system. The European standard uses 625 horizontal lines with a field taking 1/50 of a second and a frame 1/25 of a second and a repetition rate of 25 fps.

2.6.1.1 Raster Scanning

In the NTSC system the first picture field is created by scan-ning 2621/2 horizontal lines. The second field of the frame contains the second 2621/2 lines, which are synchronized so that they fall between the gaps of the first field lines thus producing one completely interlaced picture frame containing 525 lines. The scan lines of the second field fall exactly halfway between the lines of the first field resulting in a 2-to-1 interlace system. As shown in Figure 2-18 the first field starts at the upper-left corner (of the camera sensor or the CRT monitor) and progresses down the sensor (or screen), line by line, until it ends at the bottom center of the scan.

Likewise the second field starts at the top center of the screen and ends at the lower-right corner. Each time one line in the field traverses from the left side of the scan to the right it corresponds to one horizontal line as shown in the video waveform at the bottom of Figure 2-18. The video waveform consists of negative synchronization pulses and positive picture information. The horizontal and vertical synchronization pulses are used by the video monitor (and VCR, DVR, or video printer) to synchronize the video picture and paint an exact replica in time and intensity of the camera scanning function onto the mon-itor face. Black picture information is indicated on the waveform at the bottom (approximately 0 volts) and the white picture information at the top (1 volt). The ampli-tude of a standard NTSC signal is 1.4 volts peak to peak. In the 525-line system the picture information consists of approximately 512 lines. The lines with no picture infor-mation are necessary for vertical blanking, which is the time when the camera electronics or the beam in the mon-itor CRT moves from the bottom to the top to start a new field.

Random-interlace cameras do not provide complete syn-chronization between the first and the second fields. The horizontal and the vertical scan frequencies are not locked together and therefore fields do not interlace exactly. This condition, however, results in an acceptable picture, and the asynchronous condition is difficult to detect. The 2-to-1 interlace system has an advantage when multiple cameras are used with multiple monitors and/or recorders in that they prevent jump or jitter when switching from one camera to the next.

The scanning process for solid-state cameras is differ-ent. The solid-state sensor consists of an array of very small picture elements (pixels) that are read out serially (sequentially) by the camera electronics to produce the same NTSC format—525 TV lines in 1/30 of a second (30 fps)—as shown in Figure 2-19.

The use of digital cameras and digital monitors has changed the way the camera and monitor signals are pro-cessed, transmitted, and displayed. The final presentation on the monitor looks similar to the analog method but instead of seeing 525 horizontal lines (NTSC system), individual pixels are seen in a row and column format. In the digital system the camera scene is divided into rows and columns of individual pixels (small points in the scene) each representing the light intensity and color for each point in the scene. The digitized scene signal is transmitted to the digital display be it LCD, plasma, or other, and reproduced on the monitor screen pixel-by-pixel providing a faithful representation of the original scene.

2.6.1.2 Digital and Progressive Scan

The digital scanning is accomplished in either the 2-to-1 interlace mode as in the analog system, or in a progres-sive mode. In the progressive mode each line is scanned in linear sequence: line 1, then line 2, line 3, etc. Solid-state camera sensors and monitor displays can be man-ufactured with a variety of horizontal and vertical pixels formats. The standard aspect ratio is 4:3 as in the analog system, the wide-screen 16:9, and others are used. Like-wise there are many different combinations of the num-ber of pixels in the sensor and display available. Some standard formats for color CCD cameras are 512 h × 492 v for 330 TV line resolution and 768 h × 494 v for 480 TV line resolution, and for color LCD monitors is 1280 h × 1024 v.

2.6.2 Solid-State Cameras

Video security cameras have gone through rapid techno-logical change during the last half of the 1980s to the present. For decades the vidicon tube camera was the only security camera available. In the 1980s the more sensitive and rugged silicon-diode tube camera was the best avail-able. In the late 1980s the invention and development of the digital CCD and later the CMOS cameras replaced the tube camera. This technology coincided with rapid advancement in DSP in cameras, the IP camera, and use of digital transmission of the video signal over local and wide area networks and the Internet.

The two generic solid-state cameras accounting for most security applications are the CCD and the CMOS.

FIGURE 2-19 Digital and progressive scanning process and video display signal

The first generation of solid-state cameras available from most manufacturers had 2/3-inch (sensor diagonal) and 1/2-inch sensor formats. As the technology improved, smaller formats evolved. Most solid-state cameras in use today are available in three image sensor formats: 1/2-, 1/3-, and 1/4-inch. The 1/2-inch format produces higher resolution and sensitivity at a higher cost. The 1/2-inch and smaller formats permitted the use of smaller, less expensive lenses as compared with the larger formats. Many manufacturers now produce 1/3-inch and 1/4-inch format cameras with excellent resolution and light sensi-tivity. Solid-state sensor cameras are superior to their pre-decessors because of their: (1) precise, repeatable pixel geometry, (2) low power requirements, (3) small size, (4) excellent color rendition and stability, and (5) ruggedness and long life expectancy. At present, solid-state cameras have settled into three main categories: (1) analog, (2) digital, and (3) Internet.

2.6.2.1 Analog

2.6.2.2 Digital

Since the second half of 1990s there has been an increased use of DSP in cameras. It significantly improves the per-formance of the camera by: (1) automatically adjusting to large light level changes (eliminating the automatic-iris),

(2) integrating the VMD into the camera, and (3) auto-matically switching the camera from color operation to higher sensitivity monochrome operation, as well as other features and enhancements.

2.6.2.3 Internet

The most recent camera technology advancement is man-ifest in the IP camera. This camera is configured with electronics that connects to the Internet, WWW network through an Internet service provider (ISP). Each camera is provided with a registered Internet address and can transmit the video image anywhere on the network. This is really remote video monitoring at its best! The camera site is viewed from anywhere by entering the camera Inter-net address (ID number) and proper password. Password security is used so that only authorized users can enter the

2.6.3 Low-Light-Level Intensified Camera

When a security application requires viewing during night-time conditions where the available light is moonlight, starlight, or other residual reflected light, and the surveil-lance must be covert (no active illumination like IR LEDs),

BL intensified CCD cameras are used. The ICCD cam-eras have sensitivities between 100 and 1000 times higher than the best solid-state cameras. The increased sensitivity is obtained through the use of a light amplifier mounted in between the lens and the CCD sensor. LLL cameras cost between 10 and 20 times more than CCD cameras. Chapter 19 describes the characteristics of these cameras.

2.6.4 Thermal Imaging Camera

An alternative to the ICCD camera is the thermal IR camera. Visual cameras see only visible light energy from the blue end of the visible spectrum to the red end (approximately 400–700 nanometers). Some monochrome cameras see beyond the visible region into the near-IR region of the spectrum up to 1000 nanometers (nm). This IR energy, however, is not thermal IR energy. Thermal IR cameras using thermal sensors respond to thermal energy in the 3–5 micrometer (m) and 8–14 m

range. The IR sensors respond to the changes in heat (ther-mal) energy emitted by the targets in the scene. Thermal imaging cameras can operate in complete darkness. They require no visible or IR illumination whatever. They are truly passive nighttime monochrome imaging sensors. They can detect humans and any other warm objects (ani-mals, vehicle engines, ships, aircraft, warm/hot spots in buildings) or other objects against a scene background.

2.6.5 Panoramic 360 Camera

Powerful mathematical techniques combined with the unique 360 panoramic lens (see Section 2.5.4) have made possible a 360 panoramic camera. In operation the lens collects and focuses the 360 horizontal by up to 90 ver-tical scene (one-half of a sphere, a hemisphere) onto the camera sensor. The image takes the form of a “donut” on the sensor (Figure 2-20).

The camera/lens is located at the origin (0). The scene is represented by the surface of the hemisphere. As shown, a small part (slice) of the scene area (A,B,C,D) is “mapped” onto the sensor as a,b,c,d. In this way the full scene is mapped onto the sensor. Direct presentation of the donut-ring video image onto the monitor does not result in a useful picture to work with. That is where the use of a

FIGURE 2-20 Panoramic 360 camera

powerful mathematical algorithm comes in. Digital pro-cessing in the computer using the algorithm transforms the donut-shaped image into the normal format seen on a monitor, i.e. horizontal and vertical.

All of the 0 to 360 horizontal by 90 vertical images can-not be presented on a monitor in a useful way – there is just too much picture “squeezed” into the small screen area. This condition is solved by computer software by looking at only a section of the entire scene at any particular time. The main attributes of the panoramic system are:

(1) captures a full 360 FOV, (2) can digitally pan/tilt to anywhere in the scene and digitally zoom any scene area,

(3) has no moving parts (no motors, etc. that can wear out), and (4) multiple operators can view any part of the scene in real-time or at a later time.

The panoramic camera requires a high resolution cam-era since so much scene information is contained in the image. Camera technology has progressed so that these digital cameras are available and can present a good image of a zoomed-in portion of the panoramic scene.

2.7 TRANSMISSION

By definition, the camera must be remotely located from the monitor and therefore the video signal must be trans-mitted by some means from one location to another. In security applications, the distance between the camera and

the monitor may be from tens of feet to many miles or per-haps completely around the globe. The transmission path may be inside buildings, outside buildings, above ground, under ground, through the atmosphere, or in almost any environment imaginable. For this reason the transmission means must be carefully assessed and an optimum choice of hardware made to satisfactorily transmit the video signal from the camera to the monitoring site. There are many ways to transmit the video signal from the camera to the monitoring site. Figure 2-21 shows some examples of trans-mission cables.

The signal can be analog or digital. The signal can be transmitted via electrical conductors using coaxial cable or UTP, by fiber optic, by LAN or WAN, intranet or Internet.

Particular attention should be paid to transmission means when transmitting color video signals since the color signal is significantly more complex and susceptible to distortion than monochrome. Chapters 6 and 7 describe and analyze the characteristics, advantages, and disadvan-tages of all of the transmission means and the hardware available to transmit the video signal.

2.7.1 Hard-Wired

There are several hard-wired means for transmitting a video signal, including coaxial cable, UTP, LAN, WAN, intranet, Internet, and fiber-optic cable. Fiber-optic cable

COAXIAL

CABLE

FIBER-OPTIC

CABLE

FIGURE 2-21 Hard wired copper and fiber-optic transmission means

is used for long distances and when there is interfering electrical noise. Local area networks and Internet connec-tions are digital transmission techniques used in larger security systems and where the signal must be transmitted over existing computer networks or over long distances.

2.7.1.1 Coaxial Cable

The most common video signal transmission method is the coaxial cable. This cable has been used since the inception of CCTV and continues to be used to this day. The cable is inexpensive, easy to terminate at the camera and monitor ends, and transmits a faithful video signal with little or no distortion or loss. This cable has a 75 ohm electrical impedance which matches the impedance of the camera and monitor insuring a distortion-free video image. This coaxial cable has a copper electrical shield and center conductor works well over distances up to 1000 feet.

2.7.1.2 Unshielded Twisted Pair

In the 1990s unshielded twisted pair (UTP) video trans-mission came into vogue. The technique uses a trans-mitter at the camera and a receiver at the monitor with two twisted copper wires connecting them. Several rea-sons for its increased popularity are: (1) can be used over longer distances than coaxial cable, (2) uses inexpensive wire, (3) many locations already have two-wire twisted-pair installed, (4) low-cost transmitter and receiver, and

(5) higher electrical noise immunity as compared to coax-ial cable. The UTP using a sophisticated electronic trans-mitter and receiver can transmit the video signal up to 2000–3000 feet.

2.7.1.3 LAN, WAN, Intranet and Internet

The evolution of the LAN, WAN, intranet and Inter-net revolutionized the transmission of video signals in a new form—digital—which significantly expanded the scope and effectiveness of video for security systems. The widespread use of business computers and consequent use of these networks provided an existing digital network pro-tocol and communications suitable for video transmission. The Internet and WWW attained widespread use in the late 1990s and truly revolutionized digital video transmis-sion. This global computer network provided the digital backbone path to transmit digital video, audio, and com-mand signals from anywhere on the globe.

The video signal transmission techniques described so far provide a means for real-time transmission of a video signal, requiring a full 4.2 MHz bandwidth to reproduce real-time motion. When these techniques cannot be used for real-time video, alternative digital techniques are used. In these systems, a non-real-time video transmission takes place, so that some scene action is lost. Depending on the action in the scene, the resolution, from near real-time

(15 fps.) to slow-scan (a few frames/sec) of the video image are transmitted. The digitized and compressed video signal is transmitted over a LAN or Internet network and decom-pressed and reconstructed at the receiver/monitoring site.

2.7.2 Wireless

In legacy analog video surveillance systems, it is often more economical or beneficial to transmit the real-time video signal without cable—wireless—from the camera to the monitor using a radio frequency (RF) or IR atmospheric link. In digital video systems using digital transmission, the use of wireless networks (WiFi) permits routing the video and control signals to any remote location. In both the analog and the digital systems some form of video scram-bling or encryption is often used to remove the possibility of eavesdropping by unauthorized personnel outside the system. Three important applications for wireless trans-mission are: (1) covert and portable rapid deployment video installations, (2) building-to-building transmission over a roadway, and (3) parking lot light poles to building. The Federal Communications Commission (FCC) restricts some wireless transmitting devices using microwave fre-quencies or RF to government and law enforcement use but has given approval for many RF and microwave trans-mitters for general security use. These FCC approved devices operate above the normal television frequency bands at approximately 920 MHz, 2.4 GHz, and 5.8 GHz. The atmospheric IR link is used when a high security link is required. This link does not require an FCC approval and transmits a video image over a narrow beam of visi-ble light or near-IR energy. The beam is very difficult to intercept (tap). Figure 2-22 illustrates some of the wireless transmission techniques available today.

2.7.3 Fiber Optics

Fiber-optic transmission technology has advanced signif-icantly in the last 5–10 years and represents a highly reliable, secure means of transmission. Fiber-optic trans-mission holds several significant advantages over other hard-wired systems: (1) very long transmission paths up to many miles without any significant degradation in the video signal with monochrome or color, (2) immunity to external electrical disturbances from weather or electrical equipment, (3) very wide bandwidth, permitting one or more video, control, and audio signals to be multiplexed on a single fiber, and (4) resistance to tapping (eavesdrop-ping) and therefore a very secure transmission means.

While the installation and termination of fiber-optic cable requires a more skilled technician, it is well within the capability of qualified security installers. Many hard-wired installations requiring the optimum color and reso-lution rendition use fiber-optic cable.