In the earliest days, security video was an expensive rarity, with even the largest multi-national corporations having no more than a few video cameras watching over their most critical assets.

Recorders were unheard of and each camera was wired to an individual video monitor, watched over by a 24 hour guard post.

Today, I have a 16 channel Digital Video Recorder and a complement of video cameras watching my home and property. When I received a telephone call in Beirut, Lebanon, from my alarm company in Houston, Texas, telling me that a glass break sensor had triggered on my home in Texas, I asked them to roll the police and then checked my video system to discover that my gardener was mowing the lawn next to the very window that reported the alarm. Although the police found nothing, a check of my home by my wife uncovered a small crack from a stone that was launched by the lawn mower. So how did we come from only a few cameras for multi-national firms to private individual assessing alarms from half-way around the world?

The answer is commoditization. I am old enough to remember when the first video cameras were produced for the market with a price of less than $1,000 each. Integrators exclaimed: “Oh the horror! This will be the end of the security video market! How will we ever be able to make money on security video if cameras are priced under $1,000?” Quite the opposite happened. Today security video is the largest segment of the security technology market and small security installers have evolved into large multi-national firms doing quite well, thank you.

As prices fell, consumer demand increased. The technology has gone through the following phases:

All of this was driven by continuously falling prices, and demand increased. Increasing demand has driven technological development.

Video cameras are an amazing invention. Light falls through a lens onto an imager and is converted into electric signals only to be re-assembled as an image on a video monitor or storage device. In the earliest days, this was all done using analog signals. Today, the imagers are digital devices (basically an array of transistors with no cover on the circuit so that light can fall directly onto the transistors). In the case of digital video cameras, this digital imaging device is converted through a standardized digital compression algorithm such as MJPEG, MPEG-4, or H.264, and it is transmitted via TCP/IP to a digital video recorder or server where it is distributed for display on a computer monitor and recorded onto a hard disk. That is the logical development of the industry. But we are not quite there yet.

For some unknown reason, in many (analog) cameras, the digital image is converted to an analog signal where it is transmitted over coaxial wire to the analog input of a digital video recorder where the analog image is converted into a digital image to be displayed and stored digitally. Ok, am I the only one wondering why they convert a digital image to an analog image only to re-convert it back to digital? This is how all technology evolves.

Today, the following types of cameras are available, and in most cases they are available in both analog and digital versions:

Lighting is essential to good video images. However good lighting is not always available so it pays to know how different cameras will perform under different lighting conditions. First, here is a basic primer on lighting.

Most color cameras today have an automatic white balance adjustment to assist them in displaying lighting that appears to be more true to the colors we see. While this circuit helps adjust for true color, the results are not always ideal.

Dynamic Range is the camera's ability to differentiate the extremes of light and dark within a scene, especially when one is close to the other. Wide Dynamic Range video cameras use processing circuitry to down-contrast light areas and dark areas so that the overall scene becomes more readable. Our eyes do this trick naturally. WDR works best, for example, when we need to see a subject close to or standing in front of a bright window.

WDR cameras should not be used everywhere. Using WDR in evenly lit scenes results in less overall contrast and a less readable scene.

Most display devices today are LCD or LED computer screens. Older display devices included Cathode Ray Tube (CRT) computer screens, Plasma screens, and Analog CRT Video monitors. The best display devices provide fast refresh rates, very high resolution, and very high contrast.

In the early days of security video, video was recorded on Open Reel 2" Videotape Recorders. This was entirely impractical and soon gave way to recording video on VHS video cassettes. This was shortly followed by Time-lapse VHS recorders, which have given way to modern digital recording. Today, security video is recorded on either Digital Video Recorders (DVRs) or Network Video Recording Systems.

DVRs (Figure 21.1) receive either analog or digital video inputs (depending on the brand and model), and for analog inputs, they digitize the video (convert it from analog to a digital signal). Most DVRs also compress the video into a digital format that is more compact than raw video to save storage space. The video is stored on internal or attached hard disk drives (a few also have tape drives for back-up). DVRs may operate alone or networked together as a group. Most DVRs can support a workstation directly with intrinsic software or software that resides on the workstation. Networked DVRs provide the workstation with the ability to view multiple cameras on multiple DVRs. The key element defining DVRs is that cameras typically connect directly to the DVR.

Network Video Recording systems are available in several versions, but they all share the ability to work only with pre-digitized sources that are received across the network, and not directly onto the recorder.

Some DVRs can connect with dedicated Network Video Recorders that are designed to work with specific brands of DVRs. Most Network Recording Systems are designed to work with Server-based Digital Video Systems. Server-based Digital Video Systems use a quantity rating from 1 to N servers (Figure 21.2). In a server-based system video cameras are digitally encoded either within the video camera (digital camera) or through a digital encoder. Both the cameras and the servers connect to the security system network. This allows cameras to be placed widely among floors, buildings, and campuses and still to all be centrally recorded on the servers with a minimum of wiring. This would not be possible using DVRs.

Server-based systems also have the advantage of being able to provide Fail-Over servers so that if one server fails, another takes its role instantly, recording to the same or different recording media. Fail-Over servers can also record to redundant media so that even if the media fails, the recording is intact.

Several video recording schemes are available using server-based systems. These include:

Internal Hard Disk Storage (HDS) is common on Fail-Over servers where the need to record may be short-term (such as hours or a couple of days). Internal HDS is also common on very small systems where there is only a single server and few cameras.

Direct Attached Storage (DAS; Figure 21.3) is usually configured as an external hard disk that is directly connected to the server (not through a network). This is also common on small systems with a single server. DAS usually provides more storage than HDS. DAS systems typically have from 1 to 8 hard disks in a common enclosure, and these are usually connected through a Firewire or USB-2 port.

Network Attached Storage (NAS; Figure 21.4) is generally similar to DAS in that it is a box of hard disks (Just a Bunch of Drives, JBOD) except that instead of the box connecting to a single server, it connects to the same network that the servers and cameras or encoders are connected to. NAS has the ability to share its storage across a small number of servers.

A Storage Area Network (SAN; Figure 21.5) comprises one or more JBODs that are controlled by a SAN Switch. The SAN Switch directs incoming data from video sources (cameras and encoders) to the drives in the JBOD. SANs can store enormous amounts of data. It is not at all unusual to store over 200 Terabytes (TB) of video on SANs.

Both NAS and SAN storage configures multiple hard disk drives into RAID Arrays that provide more reliability and redundancy than conventional single-disk storage. The most common RAID Arrays for Security Video are RAID-0 and RAID-5. The RAID-0 storage mirror is two or more drives so that the data is completely redundant between the drives. RAID-0 is used for the server Operating Systems and Programs. RAID-5 uses “striping” to span the data across many drives. This process provides a great deal of reliability and redundancy of the data. RAID-5 storage is often used to store video and other data.

Of all the different types of alarm sensors, one of the most useful types is Video Motion Detection (VMD). VMD does what it says: it compares subsequent frames of video from a camera comparing one frame to the next looking for any differences between the subsequent frames. When the VMD sees a difference, an alarm is sent to the monitoring workstation. Virtually all VMDs break the image into many small cells and allow the user to identify which cells are to be used for motion detection and which will allow motion without creating an alarm. This is useful, for example, to detect motion in a storage yard while ignoring motion in an adjacent street. VMDs also let the user adjust sensitivity for each cell, and most have other useful settings to optimize the motion detection. VMDs were originally discrete hardware boxes, but now virtually all are in the form of software algorithms that are built into the DVRs or Archive Servers.

VMDs are a very basic form of Video Analytic process. Just as an algorithm can be written to detect motion, so can many other algorithms be written to detect other specific behaviors within the scene view of the video camera. Common Video Analytics include:

There are two basic types of Video Analytics: those that have specific algorithms to detect specific behaviors and a newer type that uses no algorithm at all. Instead the second type uses Artificial Intelligence (AI) to allow the Video Analytic to “learn” what normal behavior is within the scene view of the camera. Night versus day, busy at morning, lunch and evening rush hours and quiet in between, vehicle traffic moves according to normal traffic rules, and so forth. So when a pedestrian walks in through a vehicle exit gate. that action is detected as abnormal behavior. When a pedestrian walks across the scene carrying an AK-47, this is a profile that the system has never seen before so it yields an alarm. It would do the same if the person was carrying a banjo. When a fight breaks out inside a gymnasium, it yields an alarm. There is no specific algorithm for most of these but the AI system “learns” to detect unwanted behavior that might never have been imagined by the user. AI systems are the future of Video Analytics (Figure 21.6).

Video systems can interface to other systems in a variety of ways. The most common of these include:

After an alarm is detected using the alarm system and assessed using the video system, the Security Console Officer will communicate with roving guards using 2-way radios to direct them to respond.

A good 2-way radio system should include:

Today it is common to supply each security officer at a post or on patrol with an earpiece and microphone so that discrete messages can be communicated to remote officers and without disturbing those nearby.

Two-way radios are available in two common frequencies — Very High Frequency (VHF) and Ultra High Frequency, (UHF) — and two common types (analog and digital). Radios are available either openly transmitting or transmitting encrypted communications. Both VHF and UHF radios require licensing in most areas of the world. Most security organizations today prefer digital encrypted radios to ensure that security communications are not publically available.

Telephones are the heart of all security communications with the greater organization and the outside world. Virtually all communications with other units of the organization are handled by the internal telephone system and Security Units routinely reach for the phone to call police, fire, ambulance, and other outside services.

Security Consoles should be equipped with two types of phones: PABX (or VOIP) and one or two fixed line phones that connect directly to the telephone company's Central Office (Fixed C.O. Line). Normally the console is equipped with one or more PABX or VOIP phone extensions, which provide connection to outside telephone lines and the organization's internal phone intercom system. This is the main telephone system that the Console will rely on for most outside communications.

The fixed C.O. Lines are used for emergencies. Typically two lines are used and these are programmed such that only one line must be called to reach both (rollover phone number). This is the number given to branch offices for emergencies. It is the number that voice alarm dialers at remote branches call to advise the Security Console of an alarm (if voice is used). And it is the line that the Security Console Officers will use when the PABS/VOIP lines are all down and not working (and you can bet that will happen).

Most Security Units use a dedicated Security Intercom system to communicate with

Security Intercoms provide access to Security for people all over the facility. Additionally the system, using intercom bullhorns, allows the Security Console Officers to address intruders and suspicious people outside and inside.

There are three common types of Field Intercom Stations:

Small intercom systems use 2 or 4 wires to communicate from one or more master stations to a number of intercom field stations. These systems use analog audio components and require extensive dedicated wiring. As such, they are relatively inflexible for expansion and functional changes.

Larger analog intercom systems use a centralized or network of matrix switches (one in each building) to connect field intercom stations to a common audio and control buss that runs between buildings and back to the Central Console.

Newer intercoms use a digital infrastructure (TCP/IP) to connect remote field stations anywhere in the world to intercom master stations also located anywhere in the world. They use the organization's own TCP/IP network for communications. This allows a single Security Console to monitor intercoms at the organization's facilities located around the world.

Finally, Hybrid Matrix Switchers allow migration of older intercoms to a digital infrastructure. These have an analog matrix switch and a digital intercom all built into one allowing the organization to use its existing analog intercom infrastructure while converting new work to digital, all answered from the same intercom master stations. These systems also allow older analog stations to be answered anywhere in the world.

There are times when Security needs to speak to large numbers of people, such as immediately before or after a natural disaster, such as a hurricane or earthquake, in order to warn people and guide them to safety.

Many facilities are equipped with loudspeakers that play background music or “white noise” to make workspaces more livable. These systems can be used as Public Address (PA) Systems by adding PA amplifiers and a zoned switching circuit to lift the speakers from the primary music or noise source and place them onto the PA source.

Coupled with a microphone and zone selection switches at the Console (or using a computer microphone and zone switching system), those speakers that already exist in the workplace can serve a second valuable function.

Nextel phones are special cell phones that also have a 2-way radio function, allowing one user to speak hands-free with one or many other users. Groups of users can be set up so that the Maintenance or Security Unit can speak to technicians or guards. This is a great way to use one technology for two purposes.

Nextel phones can also be integrated into the Security Console just like 2-way radios using specialized adaptive hardware.

For every important communication, there will be some need to report it. The best way to make sure that the report is accurate is to record all verbal communications by using a Voice logger. Early Voice Loggers comprised reel-to-reel audio tape recorders and lots and lots of tape running at very slow speeds (15/16" per second). These were replaced by slow speed audio cassettes. Modern Voice Loggers use digital multi-track recording to log and preserve conversations from telephones, 2-way radios, intercoms, PA systems, and even Nextel Phones. All conversations are imprinted with a date/time code from a source that is synchronized with the Alarm/Access Control System and Digital Video System so that all communications can be heard in the context of events recorded in those systems as well.

One of the emerging technologies that shows great promise is the use of smart phones and tablet computers to send situational awareness, alarm, video, and even audio to roving guards who are responding to an alarm. These use the public cellular network to pipe high-speed data to the smart phones and tablets. Expect to see more of this in the future.

At many consoles it is common to see several telephones, a security intercom, 2-way radios, PA systems, and several different elevator intercoms (several for each building on a campus). Console Officers are expected to manage all of these different communications devices. Which they do … until there is an emergency such as an earthquake. Then, as they say, “all hell breaks loose.” And quite literally every communications device is ringing for attention. Remember now, the Security Console Officer has two ears, one mouth, and only one brain, so quite naturally he is incapable of answering all these urgent calls, including of course, those urgent calls for medical attention or say, people trapped in elevators. So how can he sort out the critical from the simply curious (“Uh, what just happened”)? The answer is a Consolidated Communications System (CCS).

A CCS manages all of the communications devices and prioritizes the calls into a queue for the Console Officer to answer. For example, for people trapped in an elevator, a recorded ring tone is heard by the Console officer when they push the elevator intercom inside the lift. This is a familiar and comforting sound that gives the Console Officer perhaps 20 seconds to answer (10 rings), after which the digital recording announces “There has been an emergency in the building that is placing a high demand on the Security Console. If you have a medical emergency please press the call button twice, otherwise, you are in a queue and please be patient for an answer.”

I first designed a CCS in the late 1980s for a campus of high-rise buildings. The design called for 100% custom technology. Today the major digital switch company makes a CCS that can integrate all types of communications hardware off-the-shelf and program it to perform functions like the one I just mentioned. CCSs are useful for large campus facilities and enterprise-class security organizations.