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A system to satisfy.


A CLOSED-CIRCUIT TELEVISION (CCTV) SYSTEM IS AN amalgam with a variety of logical ways to group parts from multiple manufacturers. Different equipment arrangements fulfill different needs. The trick to setting up an efficient system is to have a clear purpose in mind and then design the system to meet the objectives.

Common reasons for using CCTV are cost savings, observation, deterrent value, audit trail, alarm verification, and authentication. The cost of maintaining security personnel continues to escalate. In many areas, the supply of security officers is virtually nonexistent, with contract security companies busing workers to jobs from remote areas. This shortage of trained personnel is leading to increased wages for security officers. Higher wages in turn lead to increased use of automatic security systems. Increasing automation is an attempt to make the security staff as effective as possible by allowing an officer to be in more than one place at one time. Well-designed CCTV systems can be a cost-effective approach to increasing efficiency.

Observation - monitoring an area or a process - is another of a CCTV system's objectives. Continual observation or surveillance requires conscientious operators and reliable equipment. For example, parking lot observation is only as valuable as the operator is vigilant. Concentrating on this type of activity for an extended period is extremely difficult for many people, with some personality types more suited for this work than others.

When observing a brief process, an operator's concentration is well focused and probably closer to the expected level. An example of a brief process is loading unembossed credit card blanks at the embossing center of a financial institution. Lockdown processes are coordinated with control procedures, which may include monitoring the cards by CCTV from the delivery truck to the loading dock, into an elevator, within the elevator, and all the way into the vault.

Another process observation is auditing employees who handle cash in financial institutions and gambling establishments. Individuals' actions are taped and periodically viewed for procedure violations.

CCTV's deterrent value is a topic of debate. The concept of deterrence is generally accepted as valid even though statistics supporting the concept are difficult to locate.

Unmonitored cameras have also raised the question of liability. Case law is not clearly defined now and may never be. However, decisions that form case law come from jury opinions. As public knowledge of the uses of security equipment grows, acceptance of recorded rather than monitored cameras may render the liability issue irrelevant.

Increasingly, the most common objective of CCTV is obtaining audit trails of activity at specific posts. In audit trails, recorded activities are not viewed unless a problem has occurred, increasing operator efficiency. An example of this method is management of a property pass system that works in conjunction with access control. Established procedure calls for property to be checked out at a staffed location. Other entrances and exists of the building are open for employee use but not for removing property such as computers. Whenever movement occurs at these unstaffed portals, a VCR records the activity. If no activity occurs, the VCR does not record.

Until recently, collecting video data in a cost-efficient manner was difficult for many reasons. VCRs had to be managed, and tapes had to be changed when they were full. Many taped activities were of short duration, so when a simple time-lapse system was used, activity did not always occur when the recorder was on. When the camera was sequenced with others, the system was sometimes on the wrong camera at the time of the activity. If activity occurred in a remote building, and the recorder was in a central building, the alarm had to get back to the central system in time for the activity to be recorded. These problems have been solved using a combination of innovations that are covered later in the discussion of timing.

Verification of alarms, CCTV's next objective, greatly expands an officer's surveillance capabilities. Some security systems, such as exterior fence lines, are prone to false alarms. Animals and environmental forces trigger alarms as if they were human intruders. With CCTV, the operator can discern the difference between a deer, a cow, and an actual intruder.

For both alarm verification and observation, color monitors can be extremely useful. When intruder activity occurs over a short period of time, alerting response personnel to the color of the intruder's clothes can mean the difference between apprehending and losing the suspect.

Authentication is CCTV's last objective. CCTV authentication is not as secure as automatic systems, such as fingerprint or retinal scan, because it relies on the operator to make a comparison. However, it is commonly used when a higher than normal level of access control is needed.

The purpose of examining CCTV objectives is to design an appropiate system. Clearly, the design of an alarm response system is different from that of an observation system. Switching time in the subsecond range is a critical element in audit trail video but not in alarm response. Other considerations in structuring a system include the number of camera and monitor ports and whether a full or partial matrix switcher design is appropriate. As the following examples show, communication also plays a big part in system cost. All these factors must come together to satisfy system objectives.

THE CRITICAL ISSUES FOR ANY CCTV system are flexibility, timing, tuning, picture quality, and cost. Of those, the overriding goal is flexibility, which depends on a system's structural design. A well-designed system allows a security organization to respond to corporate growth. If a system will possibly outgrow its original setup, the matrix switching modules installed should also be appropriate for a larger design. One point is certain: Security needs vary almost daily. Constant changes make an adaptable system an enormously valuable tool.

Ten years ago, when matrix switchers were uncommon, most CCTV systems consisted of switchers that had between four and 12 camera inputs and two outputs, one called homing and the other bridging. Switchers were sometimes stacked so multiple pairs of monitors could display the same cameras - a task accomplished by looping through the switchers - hence the names bridging, homing, or looping switchers. Once set up, a system was difficult to modify. Wires had to be changed to create different configurations. Within a configuration, a program was created by selecting one of three settings for each camera in the system.

Today, new programs can be set to start automatically at a certain time or to cover a specific event. When a switcher is a full matrix, no configuration changes are required to link any camera to any monitor in any sequence. Extra coverage for special events is easily provided as long as the camera and monitor resources are available.

The second issue critical to CCTV is timing. Activity, whether observed as it happens or recorded for later viewing, takes place in a real-time environment. A major challenge facing the cost-effective design of large systems is the need for quick response to an alarm, perhaps before a picture is brought up on a monitor or recorded. A common plan is to use an access control and alarm system to collect the alarm signal required to switch the video and bring a VCR up to real time. However, most access control systems are too slow. CCTV timing problems are better understood when their history is examined.

When automated access control was first used, processors and memory were relatively expensive, so manufacturers used a single processor (host) to make all decisions. The remote system components were only concentrators and communication devices. They succeeded in automating the access decision, but communication to and from the host kept the system's response time slow and cost high. Users complained about the delay between card presentation and door unlock.

As time went on, manufacturers were able to design systems using less expensive processors and memory. This led to the use of more processors in remote equipment, with the access decision moving out toward each door. Communication speed did not have to increase. A door unlocked with subsecond response while a historical record of the transaction, as well as any alarms, traveled back to the host in a few seconds.

Delayed alarms can be a problem because most people can walk a mile in 12 minutes and run one in about five. A 12-minute mile breaks down to seven and one half feet per second. During the four seconds an alarm takes to trigger a system response, an intruder can run 30 feet and be out of camera range. One way to prevent this delay is to use video motion detection. Another is to use a system separate from the access control and alarm system for a fast response to the motion detector alarm signal.

Timing is also essential to switching in the vertical interval period of the video signal. When cameras are synchronized for the vertical interval, they appear in sequence on a monitor without rolling when changing pictures. This sychronization provides a clean, easy-to-read set of images.

Synchronization is particularly important in audit trail video. If system costs are to be justified, several cameras must be recorded on each VCR. If cameras are not synchronized, the recorder takes time to adjust when it switches from one to the next. Switching takes four seconds between pictures, even with just a few cameras, which defeats the timing objective. With synchronized cameras, pictures can be switched, so that several shots from different cameras are recorded each second.

A new switching and recording method is now available. A new synchronization product can take up to 16 camera and alarm inputs and provide one output with a code revealing which input was used. One advantage of this system is a frame-grabbing feature on each input that automatically adjusts the timing for any cameras out of synchronization. A tape played back through this device will show film only from the camera selected.

A second advantage of this device is the 16-to-one ratio of inputs to the output, which makes centralizing VCRs economically feasible. In the past, video transmission costs were too high to make VCR centralization a good business decision. Consequently, VCRs were put in remote buildings where they were very difficult to manage.

The third critical issue for CCTV systems is tuning. Merely putting pieces together does not ensure that a system will work - even the simplest system. Lenses need to be adjusted for back focus, which is the lens-to-target distance. Then each lens must be adjusted for focus and iris. Even with autoiris lenses, a camera's automatic gain control (AGC) must be turned off. Often an additional adjustment must be made.

Tuning each camera for synchronization, as opposed to using a central driver like Genlock, requires an adjustment at each camera. When long communications or transmission lines are necessary, sometimes adjustments in signal amplitude are needed to keep received signals at appropriate levels. Pan, tilt, and zoom mechanisms also require limit stops and other physical adjustments. If these adjustments are not made, an operator will damage a camera eventually.

Picture quality is the fourth critical issue and is affected by many parts of the system, particularly by the type of camera used. Five years ago, when chip technology was relatively new and expensive, many CCTV systems were installed with tube cameras. Tubes have a life of approximately two years and typically do not break. They do, however, get weak and often have a burned-in image. Frequent tube replacement required constant system maintenance. Cameras were often neglected, resulting in a poor system.

Today, any tube cameras remaining in a system should be replaced with chip cameras during normal maintenance. Only a few special applications still call for a tube camera today. One example is extremely high resolution, which is normally not required for security applications. Chip cameras typically do not degrade over time, so life-cycle costs are significantly lower than for tube cameras.

Cost is the final critical issue for CCTV systems. System design is a major factor in overall cost, particularly in the initial capital investment. Other factors also play a role, however. Flexibility and service requirements create different operating scenarios. If a system is initially designed with excess capacity and reasonable flexibility, then the cost of reconfiguration for new situations will be low, thus lowering overall cost.

MATRIX SWITCHERS ARE THE building blocks of today's large CCTV systems. Many peripherals such as control panels; pan, tilt, and zoom controls; and alarm input devices are used to round out a system. A system will not work without some of these peripherals, but the matrix switchers are the heart. (See Exhibit 1.)

The term matrix comes from the mathematical concept of a two-dimensional space defined by rows and columns. Normally, camera inputs are thought of as columns and monitor outputs are thought of as rows. (See Exhibit 2.) Within the matrix switch box are either electronic or electromechanical switches that direct a video signal from a camera column to a monitor row. Small amplifiers connect to each monitor line and, in larger switchers, to each looping camera output. These latter amplifiers allow matrix boxes to be stacked vertically to form switchers with more monitor outputs.

Matrix switchers are packaged with camera and monitor capacities. Larger switcher designs allow the matrix boxes to be stacked vertically, horizontally, or both. In one manufacturer's system, for example, the basic box size is 100 cameras by 10 monitors (100 columns by 10 rows). If a second box is connected horizontally to the first, then the switcher will accomodate 200 cameras by 10 monitors. If a second box is instead stacked vertically under the first, then the configuration will be 100 cameras by 20 monitors. This particular system can easily expand to 1,000 cameras by 1,000 monitors.

Each matrix box can hold 10 camera input cards, with each card designed for 10 cameras. This setup allows a system designer to purchase only the number of cards needed initially because more are easily added later. A 10 camera by 10 monitor box that communicates with the rest of the system is also available, allowing smaller locations to be part of the system without the expense of the larger switch box.

The video bus design, useful in many campus environments, shows how functionality and cost work together. For example, a system design is needed for a site composed of four large buildings, which are generally in a line. The central security control room (CSC) is located in Building 1 (B1). A site survey shows the the cost-effective number of cameras is as follows: Buildings 1 and 4 - 32 cameras; Buildings 2 and 3 - 45 cameras. Security needs also indicate that 14 monitors will provide the appropriate level of monitoring.

The buildings are separated by 500 feet, and the only conduit available is a single one and one-half inch inner duct in a telephone conduit. There are also manholes; the cable will possibly get wet every year. It is impossible to connect enough standard coaxial cable from each camera to a centralized matrix in Building 1. Two possible solutions come to mind. One is the use of fiber optics and a video bus concept. The second is to use broadband transmission on three coaxial cables.

Some matrix switchers require that all cameras be run home to the switching location. Others allow for the matrix switch boxes to be located wherever they are the most cost-effective. The video bus design takes advantage of remote switching capability by putting a matrix box in each building. (See Exhibits 1 and 2.) In this case, because 14 monitors are needed, two boxes of 100 by 10 should be stacked vertically, forming a 100 camera by 20 monitor system in each building. Thus, Buildings 1 and 4 need eight input cards each, and Buildings 2 and 3 need 10 each.

Between the buildings, a single run of 24 multimode fiber-optic strands allows for data transfer and 14 monitor runs, leaving eight spare fibers. Because the fiber does not conduct electricity, there are no ground loop problems, which typically arise from the separate power sources for each building. This design takes advantage of the full matrix capability of this switcher.

As mentioned earlier, another logical approach to this site is broadband system. Each video signal in each building is made into a radio frequency (RF) signal. These signals - the same ones used by cable TV systems - are transmitted over coaxial cable. Up to 100 signals can be put on a single coax. One coax is run from each of the other buildings to Building 1. (See Exhibits 3 and 4.) This allows the entire switcher to be placed in the Building 1 CSC. Centralization of the switcher has maintenance advantages but disadvantages in terms of cost.

Examining applicable transmission costs alone shows that the typical cost for a CCTV fiber transmitter and receiver pair is less than $800. Fourteen CCTV pairs and one data pair are required from Buildings 1 to 2, 2 to 3, and 3 to 4. Fiber transmitter and receiver pairs total $36,000. A broadband modulator and demodulator pair typically costs $1,200, and 32 pairs are needed for Building 4 and 45 pairs each are needed for Buildings 2 and 3. The broadband parts total $146,000. The switcher costs would be less for the broadband centralized system. The difference in cost should be reviewed to see if it will affect the decision.

The CPU and other peripherals are the same for both systems and therefore omitted from the data. Since the total number of cameras in the system is 154, a full matrix switcher of 200 by 20 will suffice. The system needs enough camera input cards to operate 160 cameras, which is 16 times 2, or 32 cards. Cards cost about $1,000 each, making the total cost $32,000. Each of the four 100 by 10 boxes costs roughly $5,000, so this switcher will cost about $52,000.

The video bus switcher requires eight matrix boxes and 36 cards, totalling $76,000. The cost for the fiber-optic cable and the broadband coaxial cable is roughly comparable. The 43 percent difference makes the video bus concept extremely cost-effective. Subjective differences in the two systems, such as capacity, reliability, and maintenance, also all favor the video bus design. (See Exhibit 5.)

ONCE THE ROW AND COLUMN REPresentation of a matrix switcher is established, some interesting system designs can be set up, such as the distributed partial matrix. Assuming that a system is in place and working well, an off-site building can be incorporated into the system. This building has 30 cameras of its own and needs local monitoring. In addition, alarm response cameras need to be brought back to the CSC. Since alarm conditions are rare, two channels of alarm video are sufficient. The local phone company can provide good quality video for these two channels over its fiber. The cost for the installation and the monthly fee is significantly less than the cost of one security post during hours the facility is closed. Payback will be achieved in eight months.

The off-site building has six monitors that are presently used 24 hours a day. Once the new system is in place, they will be used only during working hours. A local control panel that allows the operator of the building to control only the monitors at that site is needed. A 100 by 10 matrix box can be placed at the location. (See Exhibit 6.)

Matrix switchers are often capable of doing multiple actions in response to one alarm input. As long as the row and column addresses are unique for a matrix box, that box's activity will be independent of all other activity. Assuming the system is presently using the video bus with the addresses previously shown, then the place to put the off-site building is in the 400 to 499 camera columns and in the 20 to 29 monitor rows. (See Exhibit 7.)

The switcher can be programmed to switch once at the off-site building when an alarm occurs. This sends video out of a monitor port connected to one of the telephone company's video fiber-optic alarm channels to CSC and into a camera input of the large site matrix switcher. The alarm will also cause this camera input to be switched to an alarm response monitor. All these responses happen automatically and look just as if the off-site building were a complete part of the main matrix.

The six monitors used at the remote site during the day can use six of the remaining eight monitor ports in the 100 by 10 matrix box. A control panel should be placed at the remote monitoring station to give the security officer control of the portion of the overall switcher that pertains to the remote site. The system must be designed so that any operator sitting at the remote station can interact only with the cameras at that building and with the six monitor ports that go to the monitors. The operator cannot be allowed to program one of the two alarm ports.

This system has obvious limitations. The CSC cannot possibly see more than two cameras from the off-site building at one time. Due to the cost of transmission, this limitation is usually an acceptable business decision. The purpose of the system is to monitor the off-site building and view alarm areas during off hours. The flexibility of the distributed partial matrix design is a cost-effective method of achieving this objective.

AS THE MATRIX SWITCHER HAS DEveloped, so has the general expertise of users. Today, the security community is much more computer literate than it was just a couple of years ago and expects more from manufacturers in terms of control, flexibility, and data management. Many systems today still use alarm inputs that are hard-wired to camera inputs. In the distributed matrix design already described, the alarm switching would have been extremely difficult and expensive if the single alarm input in the remote building did not also trigger the switching at the CSC.

The same is true of the system control limits. The control panel at the remote building needs to control the six monitors and have access to all the cameras that are in the remote building, but it should not control the two monitor ports that are dedicated to alarm video transmission to CSC. Likewise, the CSC operator should not be able to control the six remote monitors. An operator knows he or she did not make a mistake by watching the results of the control on the monitors. Since the two operators cannot see each other's monitors, they are unaware of any action by one that affects the other. The affected operator may become confused and think the system is broken.

This control needs to be independent of the person and password at either position. An operator may work for a period at the CSC and later spend some time at the remote building. That operator's password should not be the limiting factor for the relationship between the control panel and the camera and monitor.

Regulating an operator's ability is important. A typical operator must respond to changing environmental conditions. If a problem occurs at one end of the main site, setting up a program that looks at all the cameras in that area and letting the others go unmonitored might make sense. The operator can then saturate the area visually. Once the event is over, the program can be brought back to its normal state.

A normal state is typically a program in the switcher that a supervisor sets up for a particular time. A different program can be set up for day versus night operation, and weekends may differ from nights. Managers, supervisors, and operators all need different levels of control. Some companies also have an employee who works with technical aspects of the system such as setting limits on pan, tilt, and zoom cameras and addresses on equipment.

The most flexible design for managing these varying control needs is again a matrix. This matrix, however, is a table of system functions versus operators. Often, manufacturers set up systems with hierarchical controls. The operator with the highest number has access to everything and as the assigned numbers get smaller, operators can do less. The problem with this approach is that operators cannot always do their jobs without giving another operator too much access. Heirarchial system security is important more for the prevention of honest mistakes than the control of mischief or dishonesty.

Using matrix representations of CCTV systems allows for growth to accommodate business needs. Security managers should keep the following points in mind: The most obvious initial approach may not be the most cost-effective; spend only the dollars required for the initial system; make flexibility the primary goal; and, above all, design the system to satisfy the objectives.

Edmonds H. Chandler, Jr., CPP, is CEO of Asset Protection Consultants Inc. of Walnut Creek, CA. APCI provides security consulting and engineering services to commercial, industrial, and government clients. Chandler is a member of ASIS.
COPYRIGHT 1989 American Society for Industrial Security
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 1989 Gale, Cengage Learning. All rights reserved.

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Title Annotation:Closed-Circuit Television
Author:Chandler, Edmonds H., Jr.
Publication:Security Management
Date:Nov 1, 1989
Previous Article:KISS and choose.
Next Article:Recording in a new age.

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