CCTV Technology Handbook

System Assessment and Validation for Emergency Responders (SAVER)

July 2013

Prepared by Space and Naval Warfare Systems Center Atlantic

Approved for public release, distribution is unlimited.

The CCTV Technology Handbook was funded under Interagency Agreement No.

HSHQDC-07-X-00467 from the U.S. Department of Homeland Security, Science and

Technology Directorate.

The views and opinions of authors expressed herein do not necessarily reflect those of the

U.S. Government.

Reference herein to any

specific commercial products, processes, or services by trade name,

trademark, manufacturer, or otherwise does not necessarily constitute or imply its

endorsement, recommendation, or favoring by the U.S. Government.

The information and statements contained herein shall not be used for the purposes of

advertising, nor to imply the endorsement or recommendation of the U.S. Government.

With respect to documentation contained herein, neither the U.S. Government nor any of its

employees make any warranty, express or implied, including but not limited to the warranties

of merchantability and fitness for a particular purpose. Further, neither the U.S. Government

nor any of its employees assume any legal liability or responsibility for the accuracy,

completeness, or usefulness of any information, apparatus, product or process disclosed; nor

do they represent that its use would not infringe privately owned rights.

Approved for public release, distribution is unlimited.

FOREWORD

The U.S. Department of Homeland Security (DHS) established the System Assessment and

Validation for Emergency Responders (SAVER) Program to assist emergency responders

making procurement decisions. Located within the Science and Technology Directorate (S&T)

of DHS, the SAVER Program conducts objective assessments and validations on commercial

equipment and systems and provides those results along with other relevant equipment

information to the emergency response community in an operationally useful form. SAVER

provides information on equipment that falls within the categories listed in the DHS Authorized

Equipment List (AEL). The SAVER Program mission includes:

• Conducting impartial, practitioner-relevant, operationally oriented assessments and

validations of emergency responder equipment; and

• Providing information, in the form of knowledge products, that enables

decision-makers and responders to better select, procure, use, and maintain emergency

responder equipment.

Information provided by the SAVER Program will be shared nationally with the responder

community, providing a life- and cost-saving asset to DHS, as well as to Federal, state, and local

responders.

The SAVER Program is supported by a network of Technical Agents who perform assessment

and validation activities. Further, SAVER focuses primarily on two main questions for the

emergency responder community: “What equipment is available?” and “How does it perform?”

As a SAVER Program Technical Agent, the Space and Naval Warfare Systems Center

(SPAWARSYSCEN) Atlantic has been tasked to provide expertise and analysis on key subject

areas, including communications, sensors, security, weapon detection, and surveillance, among

others. In support of this tasking, SPAWARSYSCEN Atlantic prepared the CCTV Technology

Handbook. CCTV Technologies fall under AEL reference number 14SW-01-VIDA: Systems,

Video Assessment, Security.

Visit the SAVER section of the DHS S&T website for more information on the SAVER

Program or to view additional reports on CCTV or other technologies.

POINTS OF CONTACT

National Urban Security Technology Laboratory

U.S. Department of Homeland Security

Science and Technology Directorate

201 Varick Street

New York, NY 10014

E-mail the National Security Technology Laboratory

National Urban Security Technology Laboratory SAVER Website

Space and Naval Warfare Systems Center Atlantic

Advanced Technology and Assessments Branch

P.O. Box 190022

North Charleston, SC 29419-9022

E-mail the Advanced Technology Assessments Branch

iii

TABLE OF CONTENTS

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Foreword i

Points of Contact ii

Preface vi

Introduction 1

CCTV System Design 1

2.1 Defining System Requirements 1

2.2 CCTV System Design Considerations 3

Components of CCTV Systems 9

3.1 Cameras

3.2 Lenses 15

3.3 Housing and Mounts 22

3.4 Video Monitors 25

3.5 Switchers and Multiplexers

3.6 Video Recorders

Transmission 36

4.1 Wired Transmission 36

4.2 Wireless Transmission 39

4.3 IP Network Transmission 42

Video Storage

5.1 Media Storage 44

5.2 Scalable Network Storage 45

Video Analytics 46

System Integration 46

7.1 Systems Approach 47

7.2 Integrating CCTV Components 47

7.3 Other Considerations 48

Emerging Technology 49

8.1 Digital Technologies 49

8.2 Improvements to Existing Technology 50

8.3 Major IT Trends 50

Vendor Selection Considerations 50

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9.1 Selection Criteria 50

9.2 Vendor Resources 51

Appendix A. Glossary A-1

LIST OF TABLES

Table 2-1. CCTV System Design Worksheet 7

Table 2-2. Sample Site Survey Checklist 8

Table 3-1. Standard Lenses for Image Sensor Size 17

Table 3-2. Calculating the Horizontal and Vertical FOV 18

Table 3-3. CCTV Monitor Technology Comparisons 27

Table 3-4. Video Transmission Signal Display Types 28

Table 3-5. Rear-Projection Monitor Comparisons

LIST OF FIGURES

Figure 3-1. CCTV Component Diagram Example 9

Figure 3-2. Color Reference Chart

Figure 3-3. Image from Thermal Camera 12

Figure 3-4. Representative CCTV Lens

Figure 3-5. Calculating FOV 17

Figure 3-6. Focus Chart Example 19

Figure 3-7. Distortion Comparison 20

Figure 3-8. Approximately 500 Lines of Horizontal Resolution 20

Figure 3-9. Sealed Camera Housing 23

Figure 3-10. Impact-Resistant Housing 23

Figure 3-11. Tamper-Resistant Housing 23

Figure 3-12. Bullet-Resistant Housing 23

Figure 3-13. Camera on Pan-Tilt Head with a Pole Mount 25

Figure 3-14. CRT Monitor 26

Figure 3-15. LED Tiles 30

Figure 3-16. Microprocessor-Based Switcher 31

Figure 3-17. Monitoring Station with Matrix Switcher 31

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Figure 3-18. Multiplexers 32

Figure 3-19. Hard Drive Recorder for 19-inch Rack 35

Figure 4-1. Coaxial Cable Construction 37

Figure 4-2. Telephone Network Example 38

Figure 4-3. Types of Antennas for RF Transmission 41

Figure 4-4. Typical Microwave Installation 42

Figure 4-5. IP-Based CCTV System 42

Figure 5-1. Storage Area Network 45

Figure 5-2. Network Attached Storage 46

Figure 7-1. Integrated Security System 47

CCTV Technology Handbook

PREFACE

PURPOSE

This CCTV Technology Handbook provides emergency responders, law enforcement security

managers, and other security specialists with a reference to aid in planning, designing, and

purchasing a CCTV system. This handbook includes a description of the capabilities and

limitations of CCTV components used in security applications.

SCOPE

The CCTV technologies described in this handbook include cameras, lenses, monitors,

multiplexers, recorders, transmission systems, and Internet protocol (IP)-based systems. This

handbook also provides considerations for implementing a CCTV system. An overview of video

analytics and programmatic considerations such as design, data storage and retention, cyber

security strategies, and system integration is also included. The outlook for new or improved

CCTV capabilities is briefly discussed. Information provided in this handbook was gathered

from Internet research and consultations with subject matter experts. No assertion is made that

this handbook is comprehensive in its breadth or depth. It is introductory-level information and

should not be considered a definitive reference for planning or implementing a CCTV system.

Such efforts should be undertaken only in consultation with organizations experienced in the

various phases of planning, constructing, testing, operating, and maintaining comprehensive

CCTV systems for access control, surveillance, or forensic applications.

The U.S. Government did not conduct independent tests of any CCTV products or systems and

does not warrant, guarantee, or endorse any specific products. CCTV technologies under

development or restricted to military use are not included in this handbook.

CCTV Technology Handbook

INTRODUCTION

CCTV systems provide surveillance capabilities used in the protection of people, assets, and

systems. A CCTV system serves mainly as a security force multiplier, providing surveillance for

a larger area, more of the time, than would be feasible with security personnel alone. CCTV

systems are often used to support comprehensive security systems by incorporating video

coverage and security alarms for barriers, intrusion detection, and access control. For example, a

CCTV system can provide the means to assess an alarm generated by an intrusion detection

system and record the event.

A CCTV system links a camera to a video monitor using a direct transmission system. This

differs from broadcast television where the signal is transmitted over the air and viewed with a

television. New approaches within the CCTV industry are moving towards more open

architecture and transmission methods versus the closed circuit, hard-wired connection systems

of the past.

CCTV systems have many components with a variety of functions, features, and specifications.

Key components include cameras, lenses, data distribution, power, and lighting, among others.

CCTV technologies continuously undergo feature refinements to improve performance in areas

such as digital equipment options, data storage, component miniaturization, wireless

communications, and automated image analysis.

The components, configuration options, and features available in today’s CCTV market create a

complex set of purchasing options. It is the intent of this handbook to provide information on the

capabilities and limitations of CCTV components that will aid an agency procuring a new CCTV

system or upgrading an existing one.

CCTV SYSTEM DESIGN

Following a sound design process enables organizations to make purchasing decisions that result

in the procurement and installation of a CCTV system that meets functional and operational

requirements. As CCTV is part of a multi-layered security approach, a system design should

begin with a comprehensive needs assessment to ensure security risks and mitigation plans are

identified. Clear requirements, a comprehensive site survey, and proper equipment selection and

installation must all be considered when designing a CCTV system.

2.1 Defining System Requirements

In order for an organization to properly implement a CCTV system, site-specific characteristics

need to be assessed by a knowledgeable multidisciplinary team of personnel. This team is

critical to identifying key functional and operational requirements. Functional requirements

consist of determining the area of surveillance, such as a perimeter area or an access point.

Operational requirements define what information a CCTV system will be expected to provide

given the existing operating conditions.

2.1.1 Multidisciplinary System Design Team

Organizations should begin by establishing a team of people with relevant knowledge to help

guide the CCTV system design process. The system design team should be involved in all

CCTV Technology Handbook

phases of the project to include: needs assessment, requirements development, system design and

layout, procurement, installation, and final check-out of the system. Personnel should be

included from varied internal disciplines such as security, facility maintenance and management,

and those who work directly with assets on-site or in controlled monitoring environments. The

team may opt to consult with external subject matter experts, such as electricians, systems

engineers, and information technology (IT) professionals.

2.1.2 Needs Assessment

A thorough risk and needs assessment should be conducted to identify locations or assets that

will benefit from CCTV surveillance as part of an overall security approach. Organizations can

enhance the security of facilities and critical infrastructure most effectively by defining their

overall goals and objectives for CCTV systems in terms of the requirements within their

operational environment.

A needs assessment gathers and analyzes four sets of requirements: functional, operational,

infrastructure, and video retention.

• Functional requirements–Define camera coverage needs such as surveillance of

perimeters, parking lots, and storage areas; surveillance of approaches to, and spaces

within, buildings or other structures; and surveillance of waterfronts;

• Operational requirements–Define the capabilities of the CCTV system components

that will enable it to provide the expected information under all operating conditions.

Conditions to consider in the operational environments include day and night

operations, lighting, weather conditions, and temperature changes. It is important that

operational requirements are detailed and testable. For example, waterfront

surveillance may demand that the CCTV system provide a recognizable image, during

day or night, of any type of surface watercraft operating at speeds between 0 and 60

knots in wave heights of up to 6 feet while within 500 yards of a pier;

• Infrastructure requirements–Define needs for installing or accessing fiber or

hard-wire cables, wireless networks, and power sources, to name a few, necessary to

successfully implement an integrated CCTV system; and

• Video retention requirements–Define the organization’s video retention and storage

needs.

2.1.3 CCTV Site Survey

A CCTV system’s effectiveness can be enhanced when integrated with access control, intrusion

detection, or duress systems. Successful integration requires a comprehensive site survey which

supports the development of detailed equipment specifications, installation design, and

ultimately a thorough system test.

A site survey should address all aspects of specifying and building a CCTV system and it is an

integral part of defining the requirements for discrete tasks and the role of each piece of

equipment. Whenever possible, CCTV systems should be included in the planning and design

stage of any new asset to ensure all necessary infrastructure requirements are adequately

incorporated into the overall facility or asset design.

CCTV Technology Handbook

The result of a comprehensive survey of the area in which a CCTV system is to be installed or

upgraded provides input to the requirements and design process. Considerations inherent in a

site survey include the number of operators, local and remote operator consoles, layout, light

levels, camera and lens selection and location, and power and data transmission.

2.1.4 System Layout Considerations

A key input to the design and specification of the layout of an outdoor CCTV system is the site

survey team’s collection and analysis of aerial photographs. Images can be obtained from a wide

variety of sources such as satellite photographs, local government files, privately contracted

aerial photography services, and a host of free web-based mapping applications. Aerial

photographs can provide information regarding on-site distances and blind areas where outdoor

video coverage may be needed. Additionally, aerial photographs and detailed maps can be used

during the design of the system to overlay alarm and video information useful for planning the

dispatch routes of response personnel.

Interior surveys are similar to exterior surveys. Aerial photographs can be replaced with scaled

computer aided drawings or blueprints of the facility being surveyed. These can be used to mark

potential camera site locations to identify the necessary coverage of access points, critical assets,

and desired fields of view. A camcorder is often used to determine camera positions and

evaluate video images from proposed camera locations.

An important factor in the design and layout of a CCTV system is the location of its transmission

hubs. Transmission routes channeled through a primary transmission hub could lead to a single

point of failure in which an outage of one transmitter could disable the transmission of data from

other camera sites.

2.2 CCTV System Design Considerations

System design considerations include factors such as lighting, power, transmission, and cost.

These factors are important in the design and layout of a CCTV system. In addition to these

factors, camera types, lenses, monitors, multiplexers, and other components are also important

considerations, and are discussed in Section 3.

Selection of the CCTV components is an iterative process that takes place in conjunction with

the design phase. Section 3 contains more details on common component features and

specifications that should be considered when selecting equipment for a CCTV system.

2.2.1 Lighting

Lighting strategies, camera selection, and camera location should be considered together in the

design of a CCTV system to ensure optimum performance and to prevent operational

environment conflicts. Light (or illumination) levels, both natural and artificial, affect system

requirements at different times of the day for exterior systems. Exterior cameras often require

lenses with automatic apertures to compensate for changes in light levels. Interior cameras may

require internal software to compensate for backlight, which is the contrast between low interior

light levels and high exterior daytime light levels. For example, backlight compensation allows

security personnel to see details of a person moving in front of a brightly lit window. Artificial

lighting can affect the appearance of the image as well as the operation of the CCTV system.

CCTV Technology Handbook

Types of artificial lights include:

• Fluorescent–Primarily used for indoor areas in the United States, these lights produce

a 60-hertz (Hz) flicker that can interfere with image quality;

• Incandescent–Include halogen bulbs and are used to illuminate large outdoor areas.

Incandescent lights consume more power than other lighting types and are generally

the most expensive to operate;

• High-intensity discharge (HID)–Include high- and low-pressure sodium and

metal-halide lighting and are the least expensive to operate. Low-pressure sodium

lights produce a yellow light that may distort true color reproduction on video.

Metal-halide lights provide the best color resolution. These types of lights require a

few minutes to reach their full luminance once turned on;

• Infrared (IR)–Emit light at a much longer wavelength than white lights, and are

faintly visible to the human eye as a red glow or they are not visible at all. IR lighting

provides a longer illumination range than white light and can be used for discrete or

covert CCTV system illumination. IR light can be provided by light emitting diodes

(LEDs) and lasers as well as filters on incandescent bulbs; and

• LED–Provide high levels of brightness and intensity. These lights are highly efficient,

and generate low levels of radiated heat. As such, they are increasingly used in CCTV

systems.

It is important to verify that the selected lighting technology sufficiently illuminates the area of

interest to meet the operational requirements. An overview of CCTV illumination is provided in

the Illumination for Closed Circuit Television Surveillance Systems TechNote. Detailed

information concerning lighting as it applies to security systems is available in the Security

Lighting Guide. Both of these documents can be found in the the SAVER section of the DHS

S&T website.

2.2.2 Power Distribution

A number of considerations must be taken into account when designing the power distribution

system. Therefore, it is prudent to consult licensed engineers and electricians in the design and

installation of a CCTV power distribution system.

Inadequate power is one of the most common problems with CCTV equipment and can often be

the cause of erratic or sporadic equipment behavior. Proper system performance requires a

clean, adequate power source. For example, it is possible for power to fluctuate considerably on

hot days when air conditioning units overload power grids. Therefore, agencies should plan

accordingly and specify power conditioning or backups as needed. The stability of the input

power to CCTV equipment can be determined by taking several readings of the voltage and

current levels over a short time period, or by using a voltage recorder for long-term monitoring.

An inadequate power system can affect the quality of the video across the entire system.

Placement of power components is an important design consideration. Placing low-voltage

power components near high-voltage lines can induce currents in the low-voltage system,

presenting a hazard to personnel and equipment. Alternatively, placing a power source too far

away can cause power fluctuations and also drive the installation costs up due to the larger

conductor sizes needed to reduce voltage drop over long distances. Therefore, it is advisable to

CCTV Technology Handbook

locate power sources close to CCTV equipment. In addition, uninterruptible power supplies

(UPSs) are beneficial in protecting equipment and conditioning the power. Since there are many

types of UPS products on the market, it is important to find models appropriate to the

application. Determinations about backup power requirements during a power interruption are

also important. For example, some CCTV systems may have designated primary cameras

focused on critical access points with a need for longer term backup power than secondary

cameras such as those within internal corridors.

Voltage spikes and lightning are common phenomena affecting CCTV systems. Lightning, a

common cause of voltage spikes, may cause failures and disable major pieces of equipment in

buildings. When designing a system, all pieces of electronic equipment should have sufficient

lightning suppression to help reduce damage and failures. Ground loop correctors help prevent

voltage differentials between two or more installations or pieces of equipment powered by

separate power sources (i.e., the ground loop corrector puts the separate pieces of equipment at

the same ground potential).

Components of a CCTV system should ideally have an internal regulated power supply;

however, this feature is often eliminated to reduce cost. This is particularly likely with low cost

cameras. There are power supplies available that distribute individually fused and regulated

feeds for each camera from a central location.

2.2.3 Video Transmission

Selecting the appropriate video transmission media, such as coaxial cable or unshielded twisted

pair (UTP), is one of the most important aspects of designing a quality CCTV system. A system

may include the highest quality hardware components available, but if the video signal is not

transmitted by the proper media, overall performance could be degraded. Many common

problems with video image quality can be avoided by selecting the appropriate transmission

media and following proper installation techniques and procedures.

As CCTV technology has evolved, video transmission has progressed from analog to digital

transmission. New cameras with Internet protocol (IP) capability transmit compressed video as

digital data. A drawback of IP transmissions is that video places a high demand on a network’s

bandwidth, and the tradeoff may be image quality. One potential solution for this issue is to

separate the video stream from the primary network. Section 4 provides a more detailed

discussion on video transmission and IP-based CCTV systems.

2.2.4 Scalability

Scalability of CCTV systems refers to the ability of the system to accommodate additional

components such as cameras, increased video storage, and additional monitors. Large facilities

often implement CCTV systems in stages due to budget limitations or in order to verify system

performance. The ability to easily incorporate hardware and software updates should be a

consideration of a CCTV system design.

2.2.5 Cost

Cost estimates for a CCTV system should cover all aspects of the system’s life cycle including

planning, design, installation, operation, maintenance, and personnel costs. In addition,

CCTV Technology Handbook

long-term personnel costs, such as initial and refresher training programs should be included.

Hardware and software upgrades should also be a cost consideration.

Using existing CCTV infrastructure such as cameras, camera mounts, and cable runs may reduce

costs. However, as the capabilities of cameras and information handling components of CCTV

advance, replacing old equipment and infrastructure may improve system performance and be a

more cost-effective solution.

2.2.6 Infrastructure

Each camera deployed in a CCTV system requires power and the means to transmit video data to

monitoring and storage systems. These requirements can necessitate modifications to a facility’s

infrastructure, such as installing new poles for mounting cameras. When planning a CCTV

installation, there are four important considerations:

1) To what extent can the system use existing infrastructure?

2) To what extent can the new CCTV system integrate with existing enterprise systems?

3) To what extent can the new CCTV system integrate with or complement other existing

or planned intrusion detection and access control systems?

4) To what extent can the new system operate in parallel with existing systems and which

system will influence operational procedures and response?

Employing existing infrastructure is an important factor in controlling equipment and installation

costs. For example, old coaxial cable systems can be converted to IP systems by running

Ethernet over coaxial cable with a converter module. Analog video and Ethernet can also be run

over telephone lines.

The extent to which a CCTV system integrates with the overall security program will be a major

factor in its effectiveness. Any new installation should operate in parallel with existing systems

until the new system is accepted and the old system upgraded or phased out. See Section 7 for

more details on system integration.

2.2.7 Reliability and Maintainability

Predicting the reliability and maintainability of a new CCTV system is difficult without a

demonstration period. Primary reliability and maintainability considerations include whether the

new system will be able to perform the required functions over time and to what degree

personnel can operate, maintain, and upgrade the system. Several techniques may be used to

improve user confidence in a new installation, including:

• Conferring with security and management personnel at other facilities that have

implemented similar systems or used the same vendor;

• Requesting competing vendors to run trial programs on-site or bench test equipment

prior to installation; and

• Installing new equipment on a small scale in order to verify that performance meets

the organization’s needs.

Vendor warranty terms may require that all technicians working on equipment be certified.

Some vendors may require a maintenance contract to ensure they have staff available to respond

CCTV Technology Handbook

within a specific period of time. The support requirements should be understood prior to

purchase and installation of equipment. See Section 9 for more details on vendor selection

considerations.

2.2.8 Annunciation, Assessment, and Response

The role of many CCTV systems in a comprehensive security program is to aid security

personnel. For instance, when a security alarm occurs at a location not currently displayed on a

monitor; the system can alert the operator by automatically switching the display to the location

of the security alarm. The operator can then assess the security alarm visually and dispatch

appropriate response forces.

2.2.9 Requirements and Design Worksheets

Table 2-1 lists basic questions to determine high level CCTV system requirements and to

influence the system design.

Table 2-1. CCTV System Design Worksheet

Basic Questions for Addressing CCTV System Requirements

1) What areas require coverage by the CCTV system?

2) What are the highest value assets that need to be protected? For example:

• High-value material property;

• Critical infrastructure;

• Intellectual property; and/or

• Classified material or intelligence information.

3) Where are the sites of greatest vulnerability?

4) Does the information technology infrastructure adequately support the number of

cameras?

5) Will the system integrate with an existing physical security system?

6) Will the system integrate with an existing electronic access control system?

7) Does the securi

ty budget cover regular maintenance, training, and upgrades to the

system?

8) Does the system’s installer/vendor provide adequate training to operate the system?

A sample checkl

ist containing some of the factors to consider during a site survey is provided in

Table 2-2. This checklist can be used by the design team to record the number and type of

cameras, monitors, and housings as well as address connectivity requirements.

CCTV Technology Handbook

Table 2-2. Sample Site Survey Checklist

Operational Environment

Indoor

Outdoor

Exposure to:

Water

Corrosives

Explosives

Fire

Extreme Temperatures

Location of Cameras

Access Points: Doors/Gates

Building Exterior

High-Security Interior Areas

High-Security Exterior Zones

Hallways/Corridors

Parking Lot

Perimeter

Other

Light Levels

Day Night

Lens

Wide Angle

Normal

Telephoto

Zoom

Camera Power

12 Volts Direct Current (DC)

24 Volts DC

120 Volts Alternating Current (AC)

Cameras

Indoor

Fixed Pan-Tilt-Zoom

Outdoor

Fixed Pan-Tilt-Zoom

*Total Number of Cameras

Housings

Dome

Weather-Resistant

Tamper-Resistant

Other (e.g., Specialized Housings)

Mounts

Wall Ceiling

Pole Corner

Fences Building Exterior

Display/Monitors

Size _______

Split-Screen Displays

Multi-Screen Displays

Video Walls

Recorders

Digital Video Recorders (DVRs)

Network Video Recorders (NVRs)

Hybrid DVRs

Transmission

Wired

Coaxial Twisted Pair

Fiber Optics Telephone

Category 5

Wireless

Laser

Infrared

Radio Frequency

Microwave

IP-Based

Internet Protocol (IP)-Based

Network Storage

Direct Attached Storage (DAS)

Storage Area Network (SAN)

Network Attached Storage (NAS)

Other

CCTV Technology Handbook

COMPONENTS OF CCTV SYSTEMS

CCTV uses components that are directly connected to generate, transmit, display, and store video

data. A CCTV system can be as simple as a camera purchased from a retail electronics store

connected to a video monitor. However, larger systems operated by professional security

personnel are comprised of a number of components falling into several basic categories:

• Cameras;

• Lenses;

• Housings and mounts;

• Monitors;

• Switchers and multiplexers; and

• Video recorders.

Many features exist within each of these categories that can satisfy an agency’s operational

requirements in the most challenging environments. The most complex CCTV systems may

incorporate hundreds of cameras and sensors integrated into one overall security network.

Figure 3-1 provides a CCTV component diagram example.

Figure 3-1. CCTV Component Diagram Example

Most new CCTV systems maximize the advantages of digital technologies by utilizing electronic

databases, compact components, and wireless transmission techniques. With larger quantities of

data being collected, it is essential that the system be capable of retaining data in accordance

with the organization’s policies and procedures.

3.1 Cameras

Cameras are an essential component of any CCTV system. Matching the right CCTV camera to

a particular application is increasingly complex due to rapid technological developments and a

greater range of applications. A system’s performance is affected by many factors beyond those

listed in the vendor data sheets. Effective camera selection requires detailed knowledge of the

camera, application, supporting architecture, and host environment.

CCTV Technology Handbook

All CCTV cameras include three basic elements:

• Image sensor–Converts light (photons) into electronic signals;

• Lens–Gathers light reflected from a subject and focuses the light on the image sensor;

and

• Image processing circuitry–Organizes, optimizes, and transmits video signals.

The type of camera best suited for a CCTV system depends on the operational environment and

how it will integrate into the system. The answers to the following questions may help

determine the best camera type:

• What is the desired image quality?

• What size is the desired field of view (FOV)?

• How much lighting is available?

• Will the camera be installed indoors or outdoors?

• Will the video be monitored on a full time basis?

• How will the video be transmitted?

• Will the camera be exposed to extreme conditions?

There are many types of cameras designed to perform under specific environmental conditions

but cameras can be grouped into two primary categories: fixed and pan-tilt-zoom (PTZ). Fixed

cameras are intended to constantly view a single scene, while PTZ cameras are motor driven and

can pan left or right, tilt up or down, and zoom in or out to instantly customize the view as

needed. A combination of fixed and PTZ cameras are often used to provide the required

surveillance coverage.

3.1.1 Fixed Cameras

Fixed cameras are mounted in a stationary position and are focused on a single FOV, typically

one particular area of interest. These cameras can be used indoors or outdoors and can be

installed overtly or covertly. Fixed cameras vary in size and can be mounted in a wide range of

locations (e.g., inside cabinets or control panels, or on poles, fence lines, or roofs).

Fixed cameras can be integrated with an electronic security system (ESS) and used to assess ESS

alarms. For example, a fixed camera can surveil a secured gate but only record data when the

gate opens, triggering an alarm. Fixed cameras are usually less expensive than PTZ cameras and

require less maintenance as they have fewer moving parts.

3.1.2 PTZ Cameras

PTZ cameras come in a variety of sizes and shapes for interior and exterior uses. Typically, a

PTZ camera can be turned and tilted on two axes to provide pan and tilt capabilities and the focal

length of the lens can be varied to change the FOV. This enables PTZ cameras to offer more

flexibility for viewing and capturing images in real time than fixed cameras. PTZ cameras can

be operated manually or in an automatic scan mode, thus capturing the most relevant video

possible.

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In manual mode, the operator can control the direction of the camera depending on situational

needs and zoom in on an object (e.g., a suspicious bag, a person’s facial features, or a license

plate) to capture specific details of interest.

PTZ cameras can also be configured to automatically scan back and forth over a wide area that

cannot be covered by a single fixed camera. Preset positions can be programmed to switch

views based upon specified time segments. For example, a PTZ camera could be programmed to

change its view every 10 seconds to capture different areas of interest within the camera’s

overall surveillance area.

3.1.3 Connectivity Type

CCTV cameras may employ one of two types of data transmission:

Network Cameras–Network cameras connect to IP-based networks, including the Internet, and

provide remote viewing and recording. Network cameras are also available in high definition

(HD) which can provide greater image detail.

Analog Cameras–Despite increasing use of digital network cameras, a market for analog

cameras still exists. This may be due to the cost involved in upgrading and converting to a new

transmission process. Analog cameras have options for high resolution, making them applicable

for various surveillance needs. These cameras also have some cyber security advantages because

the coaxial cable they are connected with would require physical access to breach.

3.1.4 Day/Night Cameras

Day/night cameras offer flexibility by automatically adjusting to current lighting conditions.

These cameras capture color images in daylight and switch to black-and-white to improve image

quality at night. The camera relies on an analysis of the current image or a photoelectric sensor

to determine when to automatically remove the infrared-cut filter and switch to monochrome

settings.

3.1.5 Low-Light or Night Vision Cameras

Cameras used to capture images in dark environments are either low-light or night vision

cameras.

Low-light cameras are designed to perform in some level of ambient lighting, such as indoor

restaurant lighting, street lamps, or a full moon; they are not intended for use in complete

darkness.

Night vision cameras used in CCTV systems typically consist of near-infrared (NIR) and IR

cameras with built-in IR illuminators. They are designed to allow the operator to view night

scenes. The distance from which a CCTV camera can detect objects at night depends on the

capability of the camera components, such as the lens and sensor, as well as on the intensity of

the IR illuminator used. The IR light emitted from these illuminators can be at wavelengths that

are invisible to the human eye.

The primary determinant for whether a camera transmits an image in color or monochrome

(varying tones of a single color) is the camera’s image sensor. Monochrome cameras record

images using light in NIR wavelengths outside the range of human perception

(i.e., spectroscopic) while the image sensor of a color camera uses filters on the individual light

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sensitive elements of the image sensor to limit that element to specific color wavelengths. These

filters allow the sensor to detect and transmit color in addition to light intensity, which is what an

unfiltered, monochrome sensor would detect.

Color cameras are used in daylight and well-lit night situations.

There are many applications in which accurate reproduction of color

is important. Color reference charts like that shown in Figure 3-2

provide an accurate color source for the selection/evaluation of

cameras and optics. CCTV installers and technicians often use a

color reference chart to assess the colors in an image. In addition,

waveform generators and vector scopes are also used to measure

system performance. It is important to remember that video monitor

color reproduction is also critical.

Figure 3-2.

Color Reference Chart

Monochrome cameras can capture images at night or in near-dark conditions that have more

detail than the human eye can perceive. However, images captured with a monochrome camera

during the day may lack some contrast and detail because the image is formed from visible and

infrared light, which have different planes of focus. Monochrome image sensors are made

mostly of silicon and germanium material and have two different spectral responses. This allows

the image sensors to perform well in the infrared light region.

3.1.6 Thermal Imaging Cameras

Some operational environments may require a thermal imaging camera to detect through

obstructions such as fog or smoke. Thermal imaging cameras detect infrared or heat radiation

that is invisible to the human eye. Currently these cameras are sensitive to a temperature

difference of one tenth of a degree Fahrenheit. Thermal imagers cannot detect through glass or

water, but can provide an image through limited density fog or smoke.

Many thermal imaging cameras have built-in image processing to create images with improved

contrast, like that shown in Figure 3-3. This provides better feature definition and sharper,

clearer images. Thermal cameras are often mounted in

gyro-stabilized, pan-and-tilt devices as well as on boats and

helicopters for night surveillance in poorly lit areas. They are also

available as small handheld units with built-in displays, which can

be used in safety, security, and emergency responder applications.

The image sensors in thermal cameras can degrade, so it is

important to consult with the camera manufacturer to determine

performance characteristics over time and to budget for the cost of

periodic maintenance and replacement.

Figure 3-3. Image from

Thermal Camera

3.1.7 Miniature or Covert Cameras

Special applications may exist that require the installation of small, hidden cameras as part of a

CCTV system. These cameras are not usually weather resistant, so they may require an external

housing if they are to be used outdoors. These cameras are typically battery operated and may

use built-in transmitters to provide a compact wireless solution. Organizations can choose from

many types of miniature and covert cameras depending on their requirements.

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3.1.8 Optional Camera Features

CCTV cameras can include a variety of optional features to meet the specific needs of the

operational environment. Some of these common features are described below.

Auto Scan–Some PTZ cameras can be programmed to perform automated functions. Auto scan

is the term used to describe a constant cycle of sweeping through the surveillance area.

Preset–A preset is a programmed orientation and lens setting, which a PTZ camera moves to

either periodically or when a certain type of event occurs. For example, during an intrusion

alarm, a camera can be preset to display the high-value assets in the surveillance area or to focus

on the access point where the alarm was triggered.

Privacy Masking–A camera with privacy masking capability can selectively block portions of

the video image for the purpose of protecting privacy. For example, PTZ cameras may be used

to monitor a parking lot adjacent to an apartment building with the images of the windows in the

building masked. This is a feature of the system configuration (software or hardware) and can be

complex and costly.

Slip Ring–A slip ring is an electrical connection that allows a PTZ camera to turn without

twisting the signal/control cable. Slip rings can use light beams to optically transmit the image,

or use a sliding brush contact on a base ring to create an electrical path. Slip rings tend to be

sensitive to contamination and temperature changes.

Motion Detection–Cameras can be equipped with built-in motion detection features, which can

be programmed to trigger an alarm if motion occurs within the FOV. The alarm can be

programmed to trigger recording, alert an operator, or both. Motion detection features can also

result in nuisance alarms if the environment has natural movement.

Backlight Compensation (BLC)–Some cameras have built-in BLC settings. BLC can

compensate for the high contrast of images with a bright background and enhance the image

detail accordingly. For example, BLC allows security personnel to see details of a person

moving in front of a brightly lit window.

Digital Noise Reduction (DNR)–This feature is common for cameras intended to capture

images in low-light or dark environments. DNR removes the noise (grainy appearance displayed

as spots known as “raster”) from the video image. This makes the image clearer, brighter, and

easier to interpret. Less digital noise can also reduce storage space requirements since there is

less extraneous information in the video.

Mobile Compatibility–This application enables remote viewing of video on mobile devices

such as smartphones, tablets, and laptops. Some remote viewing methods require special camera

software or hardware while other methods and applications can be configured to connect directly

with a camera and do not require a personal computer (PC).

3.1.9 Types of Image Sensors

CCTV cameras commonly use charge-coupled device (CCD) or complementary metal oxide

semiconductor (CMOS) image sensor technology. The smallest part of an image produced on a

solid-state chip is the picture element, or pixel. Regardless of the sensor type, pixels are

engineered in number, size, and filtration to provide different resolutions, light sensitivity, and

spectral responses.

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3.1.9.1 Charge-Coupled Device Sensors

Cameras that use CCD image sensors entered the CCTV industry in the mid-1980s and now

dominate the market for daylight and low-light, or NIR cameras. CCD technology has many

advantages over the tubes used in the earliest video cameras. CCD image sensors are smaller,

generate less heat, and their captured images are less susceptible to “blooming.” Blooming

occurs when the image sensor is overwhelmed by a high-intensity light source in the FOV and

eliminates details in other parts of the image. The life expectancy of a CCD camera ranges from

5 to 25 years.

CCDs consist of a three-dimensional array of pixels, each of which generates an electrical signal

proportional to the quantity of light it receives. This analog electrical signal is transferred to

another chip where it is converted to digital information. This digital information is processed

within the camera and then transmitted to other components of the CCTV system. Some

cameras convert the processed signal to analog video prior to transmission.

The surface of the type of CCD used in CCTV cameras resembles an aerial view of a very

orderly city. Each of the rooftops represents a light-sensitive element, while the streets represent

the electronic timing and control circuits. The proportion of the rooftops (sensor elements) to the

streets (circuits) determines the sensitivity to light and the resolution of the CCD. A greater area

devoted to sensor elements results in a camera with high sensitivity and finer resolution. Smaller

proportions result in lower sensitivity and a more coarse resolution. In addition, some

manufacturers offer CCDs with a lens capability for sensor elements to gather more light and

increase sensitivity.

Although CCDs are sensitive to visible light, they are also sensitive to NIR light. A sensor’s

spectral response is a function of the chemistry of some components and can be further

manipulated with filtering technologies. Filters designed to reduce or eliminate IR light, known

as “infrared-cut filters,” can be used in front of the sensors to improve a color camera’s image

(see Section 3.6.2.8 for a more detailed discussion on filters). Monochrome cameras do not have

such filters because they are intended for use near the IR spectrum. During the day,

monochrome cameras form an image using both visible and NIR light; therefore, the daytime

image may lack some clarity compared to nighttime images.

In order to increase the resolution, some cameras use three CCDs. In this configuration, a prism

splits the white light passing through the lens into red, green, and blue. Then, three monochrome

CCDs, each filtered to receive one color, calculate and combine the vector output to create a

high-resolution image. The same principles can be applied to cameras utilizing three CMOS

sensors.

3.1.9.2 CMOS Sensors

Applications requiring high-quality images tend to rely on CCD sensors, but CMOS sensors are

commonly used in applications such as network cameras, PC peripherals, and smartphones. This

is a result of CMOS sensors using less power than CCDs and being less expensive to

manufacture.

Unlike CCD sensors, CMOS sensors address each pixel individually. They process the charge

from each pixel on the sensor and transmit a digital bit of information. This technique reduces

CCTV Technology Handbook

the need for additional processing along the transmission pathway. CMOS sensors use less

power than CCDs because a larger area of the chip is devoted to processing circuits.

3.2 Lenses

The lens on a CCTV camera is the first element in the imaging

chain, which consists of the lens, camera, transmission system,

image management and analysis software, and monitor. The

lens focuses light or IR energy onto the imaging sensor. A

lens’s role is to deliver an undistorted, evenly focused,

accurate image to the imaging sensor. Systems that require

superior quality images start with lenses engineered to produce

a high-quality image for the imaging sensor. Other

components of the imaging chain cannot compensate for an

inferior lens.

Figure 3-4. Representative

CCTV Lens

Variables to consider when selecting a lens include the distance required to clearly focus on

objects, FOV, size of the camera’s image sensor, and lighting conditions. Lenses are identified

by their focal length, usually stated in millimeters; largest aperture, usually stated as an

f-number; and the size of the image sensor for which it was designed.

3.2.1 Types of Lenses

Lenses are available in three basic types: fixed focal length, varifocal (variable focal length), and

zoom. The focal length of a lens is the distance between the optical center of the lens and the

image plane. The lens focal length and the image sensor size determine the camera’s FOV.

3.2.1.1 Fixed Focal Length Lenses

Fixed focal length lenses are built with one set, unchangeable, focal length. Such lenses are

useful in situations where the camera remains in a fixed position and the requirements to observe

an area do not change.

3.2.1.2 Varifocal Lenses

The focal length of varifocal lenses can be changed within a specific range; however, each

change must be accomplished by hand at the camera. In addition, each time the focal length is

changed, the iris and focus may also need adjustment. Varifocal lenses offer the flexibility of

varying the scene content and are relatively inexpensive when compared to conventional zoom

lenses. Once the focal length and iris are set, the camera will maintain the FOV. Varifocal

lenses are identified by the focal length range, aperture range, and size of the image sensor the

lens is designed for.

3.2.1.3 Zoom Lenses

Unlike the varifocal lens, the zoom lens is designed to maintain the focus setting throughout the

focal length range. Zoom lenses in the CCTV industry are often built with integral motors to

enable changing the focal length from a remote location. They are used on cameras that monitor

different parts of a scene or can pan and tilt to monitor different locations. Zoom lenses are

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identified by their focal length range, aperture range, and the size of the imaging sensor the lens

is designed for.

3.2.1.4 Optical Versus Digital Zoom Ranges

The focal length ranges for varifocal and zoom lenses denote optical focal length ranges, which

are a function of the components of the lens. The zoom range is referred to both as a specific

range of focal lengths, such as 6 to 24 mm, and as a zoom factor, such as a 4x (four times)

multiplier. For the aforementioned focal length range of 6 to 24 mm, the zoom factor is

4x (6 x 4 = 24). It should be noted that zoom factor is not an indication of image magnification;

zoom factor is only indicative of the focal length range. Image magnification is a function of the

image sensor size and the lens focal length. Zoom lenses are often chosen so that security

personnel can use the longer focal lengths to zoom in and enlarge a specific potion of the image

to see more detail or make identification.

A digital or electronic zoom refers to the capability of the camera, or the CCTV system’s

processing software, to select and enlarge portions of the full image. In this case, only the

selected pixels are magnified. Unlike optical zoom, digital zoom does not enhance the detail of

an image, it reduces it. Digital zoom ranges are often denoted by magnification factors of

2x, 6x, etc.

3.2.2 Features of Lenses

A lens has certain components and characteristics that further determine its capabilities. These

include the focal length, type of aperture and focus control, wavelength of light or energy the

lens is optimized to transmit, and image sensor size the lens is designed for. Additionally, a

camera’s resolution and the impact of noise on the image being captured are critical to the

overall performance of a CCTV system.

3.2.2.1 Focal Length and Imager Format

The focal length and size of the image sensor determine the angle from which the lens accepts

light to focus on the image sensor. Different lenses of the same focal length are designed to

create a focused image on sensors of different sizes. For example, surveillance cameras are built

with image sensor formats of ¼, ⅓, ½, ⅔, or 1 inch. These measures refer to the approximate

diagonal measurement of the image sensor. Image sensor formats are denoted in inches, while

lens focal lengths are measured in millimeters.

A lens should be selected to match the format of the image sensor so that the image formed on

the sensor utilizes most of the available pixels. Lenses are generally marketed for cameras with

specific sizes of image sensors. The camera’s FOV is a function of the lens’s focal length and

the size of the image sensor.

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Table 3-1 shows the standard focal length lenses that correspond with several camera image

sensor formats.

Table 3-1. Standard Lenses for Image Sensor Size

Sensor Size

Standard Lens Size

⅔ inch 16 millimeter

½ inch 12 millimeter

⅓ inch 8 millimeter

Any lens with a focal length greater than the standard lens is a telephoto lens while a lens with a

focal length less than the standard lens is a wide-angle lens. Lenses with the same focal length

on a small-format camera will produce a telephoto-like image, but produce a wider image on a

large-format camera. A 12-millimeter lens can be designed for the following:

• ½-inch image format camera and will produce a standard image;

• ⅓-inch image format camera and will produce a telephoto-like image; and

• ⅔-inch image format camera and will produce a wide-angle image.

A lens built for large-format cameras may be usable on some small-format cameras; however,

the reverse is not true as corners and edges of the image will appear darker. For example, a lens

designed for a ½-inch sensor can work on a camera with a ⅓-inch sensor, but not the reverse. It

is best to use a lens designed for the size of the image sensor in the camera.

3.2.2.2 Field of View

The image sensor size and the focal length can be used

to determine the FOV. As shown in Figure 3-5, the

FOV is the area seen by the camera and lens. This area

is commonly calculated by a tool known as a lens

calculator.

CCTV Camera

Lens

D = Distance from scene to

lens

Camera FOV

Scene

Horizontal Width

Vertical Height

Figure 3-5. Calculating FOV

Table 3-2 shows how to calculate the horizontal width

and vertical height of the FOV. The FOV is calculated

using the imager format information for the camera

imager size, along with the distance to the object of

interest and the lens focal length.

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Table 3-2. Calculating the Horizontal and Vertical FOV

Imager Size

⅓ inch ½ inch ⅔ inch

Horizontal

Format

4.4 millimeters 6.4 millimeters 8.8 millimeters

Vertical Format

3.3 millimeters 4.8 millimeters 6.6 millimeters

Horizontal Width Calculation: (Horizontal Format x Distance)/Focal Length

Vertical Height Calculation: (Vertical Format x Distance)/Focal Length

Example: Using a distance of 79 feet from a camera on a building overlooking

a street, select a ⅓-inch format (imager size) camera with a 5-millimeter lens.

Horizontal width = (4.4 mm x 79 ft)/5mm = 70 ft

Vertical height = (3.3 mm x 79 ft)/5mm = 52 ft

The camera has a coverage area of 70 feet x 52 feet at a distance of 79 feet.

A common tool in the CCTV industry is the handheld, wheel-style lens calculator. It is an easy

and convenient method for determining dimensions of a scene. Wheel-style lens calculators are

widely available from CCTV vendors, generally at no cost. In addition, there are many online

lens calculators, as well as software lens calculators. They range from very simple calculators

that serve the same function as the handheld calculator to more sophisticated products that

provide additional illustrations and simulated camera views.

3.2.2.3 Iris and Aperture

The aperture is the opening in the lens which allows light to flow through the lens. Lenses with

adjustable aperture settings have a multi-leaved device, called an iris diaphragm, or iris, inside

the lens. The iris diameter changes with the aperture setting. The iris diameter regulates the

quantity of light flowing through the lens and subsequently onto the image sensor.

The iris ensures the optimum amount of light reaches the image sensor through the aperture,

providing the best image possible. This is critical to optimal image viewing. If too much light

hits the image sensor, the image will appear washed out. Too little light will result in a dark

image in which only the brightest objects in the FOV are visible.

The number that indicates a lens’s aperture setting is the ratio of the lens’s focal length to the

diameter of the aperture. This is referred to as an f-number and is calculated as:

f–number =

focal length

effective aperture

For instance, an f-number of f/2 indicates that the lens’s focal length is twice (2x) the diameter of

the aperture opening.

An important feature that differentiates lenses is whether the iris is fixed or is variable with

manual or automatic adjustments. Fixed aperture lenses may be useful in situations where the

lighting is constant. Lenses with manually adjustable apertures are primarily useful in static

viewing situations with controlled lighting. Lenses with manual adjustments cost less than

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lenses with automatic adjustments, but require a technician to change the setting. There are also

motorized lenses that allow the operator to remotely change the iris setting, focus, and zoom.

Lenses with automatic adjustable apertures are called auto-iris lenses. These lenses have a

solenoid on them that is controlled by a video signal or a direct current signal from the camera.

They are effective in outdoor environments or locations featuring extreme lighting changes.

A large aperture is an indication of the lens’s ability to transmit light in dim conditions and is

commonly expressed as an f-stop. The smaller the f-stop number, the wider the aperture.

Common f-stop values for manual lenses include 1.4, 2, 2.8, 4, 5.6, 8, 11, 16, and 22. A setting

of f/4 lets twice the light pass through the aperture as compared to a setting of f/5.6. Lenses with

large apertures, such as f/1.0, f/1.2, and f/1.4, are often referred to as “fast” lenses as they allow

more light to reach the sensor than lenses with a higher f-stop numbers, such as f/8.0 or f/11.

Lenses with higher f-stop numbers are often described as “slow.”

The aperture settings also affect the depth of field, which is the area in front of and behind an

object that appears to be in focus. Higher f-stop numbers will provide greater depths of field.

3.2.2.4 Back Focus

To be useful, the image transmitted through a lens must

be focused properly on the camera’s image sensor. This

camera adjustment is called back focusing. Cameras

differ in their method to vary the distance between the

imager surface and the lens’s mounting surface. Most

cameras have a method of moving the image sensor

forward and backward. Some have a wheel that is

rotated to move the image sensor; others have a screw

that moves an internal mechanism. Some lenses

incorporate a back focus adjustment as well. Back focus

is primarily an issue with zoom lenses.

Figure 3-6. Focus Chart Example

A zoom lens is properly back focused when the image of

a fixed object remains sharp throughout the entire zoom

range. The focus ring on the lens should not have to be

touched during this zoom operation.

To properly back focus a zoom or fixed lens, the lens aperture is set at the largest opening and

for a zoom lens the focal length is adjusted to the longest setting. In order to achieve the largest

lens aperture, use dim lighting or hold a gray neutral density filter in front of the lens to reduce

the amount of light and force the aperture to fully open. An experienced technician can often

focus the camera using a handheld monitor while viewing a detailed fixed object in the scene.

For example, technicians may place a focus chart within the scene and focus the camera until the

Moiré effect, or the moving blur in the center, is minimized.

3.2.2.5 Image Quality and CCTV Lenses

A number of factors affect how light moves through the lens and forms an image on the sensor,

one of these factors is distortion. There are two main types of distortion associated with image

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quality: barrel and pincushion. Barrel lens distortion is related to wide-angle lenses and, in

particular, a wide-angle lens that zooms. This effect causes the edges of images to appear

curved, as though they are wrapped around a curved surface. An example of barrel distortion is

provided in Figure 3-7.

Pincushion distortion is an effect most often associated with zoom telephotos that causes images

to appear pinched in the center. This distortion increases with the distance the object is from the

optical axis of the lens. Pincushion distortion is the opposite effect to barrel lens distortion.

Distortion affects the image of all objects in the FOV and the apparent relationships among

objects in space. Low distortion is important to preserve correct impressions of space and

objects. High-quality CCTV lenses have low distortion values, although distortion is not the

only criterion of quality.

Barrel Distortion No Distortion

Figure 3-7. Distortion Comparison

3.2.2.6 Resolution

The resolution of a camera is an indicator of its ability to resolve detail in an image. The

horizontal resolution of a camera can be measured using a resolution chart, as shown in

Figure 3-8. The resolution chart is composed of several, nearly parallel, lines that taper inward

so lines are smaller and spaced closer together toward the bottom of the chart. As the camera

scans from top to bottom, the point where the lines become indistinguishable establishes the

horizontal resolution, which is indicated on the scale of the chart. The vertical resolution is

limited to the number of scan lines that form the TV image and are typically not considered

because they exceed the capability of the human eye.

Figure 3-8. Approximately 500 Lines of Horizontal Resolution

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3.2.2.7 Signal-to-Noise Ratio

All circuits produce some degree of electronic noise. The amount of noise in a circuit, referred

to as the signal-to-noise ratio (SNR), is especially important whenever a signal requires

amplification or processing because amplifiers and processing components can magnify the

existing errors in the signal as well as introduce new errors. Noise in a video signal is viewed as

graininess or snow on the screen. Video noise often becomes apparent when a camera is

operating at the edge of its design parameters; for example, using a daylight color camera at dusk

or in low-light conditions often produces a noisy image.

SNR values are usually given in decibels, with higher values more desirable than lower values.

Noise can also originate outside the camera or system. Once electronic noise is present in a

video system, it is expensive and difficult to remove effectively.

3.2.2.8 Color Corrected and Monochrome Lenses

Lenses should be paired correctly with the camera selected. Color corrected lenses are designed

to focus the various colors of light onto the same image plane and create good images using

color and daylight monochrome cameras. Most lenses sold today are color corrected lenses.

Monochrome lenses are inexpensive and capable of providing an adequate image on inexpensive

monochrome cameras; however, they should not be used on color cameras. High-end

monochrome cameras, which process reflected infrared light, should be used with lenses

designed to perform well in that portion of the spectrum.

3.2.2.9 Lenses with Aspherical Elements

The glass or plastic elements used in a lens design have spherical surfaces. Computerized lens

production technologies have made the manufacture of surfaces easier and cheaper, thereby

providing lens designers greater leeway in correcting the light transmittance through a lens.

Aspherical lenses were created to eliminate spherical aberration. Spherical aberration occurs

when light from the outside of a spherical optical element in the lens converges at a different

point than the light passing through the center of the same optical element. The blurring can be

removed by using a modified curved lens with aspheric elements.

Designers can also create CCTV lenses with wide apertures that still produce useable images at

the full aperture. Lenses with apertures of f/1.0 or faster, may be more feasible with aspherical

versus traditional designs. Zoom lenses with very large focal length ranges are very difficult to

design and engineer for high image quality and thus may incorporate aspherical elements. Also,

aspherical lenses can be designed using fewer elements or smaller lenses while still maintaining

performance similar to lenses with spherical elements.

Lenses with one or more aspherical elements may or may not produce a better image than those

constructed solely of spherical elements. A well-designed, well-built lens with spherical

elements may perform better than a mediocre lens with aspherical elements. The presence of

aspherical elements does not necessarily indicate better performance than a lens with only

spherical elements.

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3.2.2.10 Filters

Filters are used to alter the amount of light or the wavelengths of light reaching the image sensor.

They are often screwed onto the front of a lens, although some are integral parts of the lens

design and rotate into and out of the light path. The most common types of filters used in the

CCTV industry are neutral density (ND), polarizing, and IR-cut filters.

Neutral density (ND) filters are used to reduce the amount of all visible light passing through

the lens when the level of the scene is too high for the camera’s image sensor. ND filters are

available in various densities to tailor the light reduction. ND filters are typically mounted to the

front of a lens.

Polarizing filters orient light in a specific direction in front of the lens. Such filters are

specifically designed to reduce or eliminate reflected light and glare from shiny surfaces, such as

water or glass. Polarizing filters can be mounted on the front of a lens and then rotated to filter

out the undesired light to increase the contrast of the image.

IR-cut filters are used to filter or block most of the NIR light energy that would otherwise reach

the image sensor. Most image sensors have significant sensitivity to NIR light. Without the

filter, the IR light from many daytime sources, including the sun, would cause the image sensor

to produce an image with unnatural, unpredictable colors and poor contrast. In color day/night

cameras, the IR-cut filters are mounted in a rotating filter ring inside the camera to allow the NIR

light to reach the image sensor when needed.

3.3 Housing and Mounts

Part of designing and installing an effective CCTV system includes selection of the camera

housings and mounts. Selecting CCTV housing and mounting hardware is directly related to the

operational system requirements, which are developed during the design and procurement phases

of a CCTV installation project. In any application, the housing and mounting hardware is

selected on the basis of several criteria:

• Environmental conditions, which include operating temperatures and weather

conditions, such as humidity and corrosion;

• Architectural considerations, which are important to the aesthetics of the hardware and

can affect the architectural design or change the value of the property; and

• Installation and other special considerations that match the installed materials to the

system’s intended use and planned maintenance.

The following hardware and mounting options are briefly described for comparison with system

requirements.

3.3.1 Camera Housing

Fixed or PTZ cameras may require special housings or enclosures to ensure cameras are

protected from elements such as extreme weather conditions and vandalism. Camera housings

must be well-suited to the type of equipment installed. The housing will need to complement the

CCTV system design and must not interfere with the desired FOV. System requirements, such

as resistance to environmental conditions, tampering, and direct assaults, can dictate the

CCTV Technology Handbook

composition and style of the camera housing. The housings listed in this section provide

enclosure protection capabilities for specialized applications.

Dome Enclosures–Indoor and outdoor domes are enclosures that protect CCTV equipment,

often PTZ cameras, from the elements and provide discrete video surveillance by helping to

conceal the direction the camera is facing. Domes can come with built-in heaters and fans as

well as vandal-resistant hardened shells. They are usually spherical in shape to minimize wind

load and vibration. Various styles and configurations are available. The optical dome must be

able to withstand temperature extremes and not become brittle or cloudy with exposure to solar

and ultraviolet radiation. Materials that lose transparency with age in sunlight are unsuitable for

outdoor camera use.

Sealed Housings–Special housings are available for cameras that must

be placed in a hostile environment, or in areas where electrical

components must be sealed to prevent a possible explosion. In these

situations, sealed and/or pressurized camera housings are available,

similar to that shown in Figure 3-9. A sealed housing uses gaskets to

prevent contamination from the outside environment. Pressurized

housings employ chemically inert nitrogen gas to replace the air inside

the housing.

Figure 3-9. Sealed

Camera Housing

Impact-Resistant Housings–Impact-resistant, or anti-vandal,

housings are often used in high crime areas or as components of

military sensor systems. Impact-resistant camera housing bodies,

like the example shown in Figure 3-10, are typically heavy-gauge

steel, and the optical surfaces are thick acrylic or polycarbonate

plastic. Some versions have a wire cage over the acrylic dome to

provide greater protection. Observation is not hindered because

the minimum focusing distance is several feet outside the wire

cage.

Figure 3-10.

Impact-Resistant Housing

Tamper-Resistant Housings–Tamper-resistant housings are

hardened protective housings similar to impact-resistant

housings, with additional protection against the use of tools to

vandalize the camera. A tamper-resistant housing is lockable

and designed to withstand cutting, hammering, or prying.

Figure 3-11.

Tamper-Resistant Housing

Bullet-Resistant Housings–Bullet-resistant housings are made of

impact-resistant materials. The window consists of at least one

thick layer of a polycarbonate material.

Figure 3-12.

Bullet-Resistant Housing

3.3.2 Housing Features

Camera housings offer an array of features intended to extend the life as well as ensure the

operational effectiveness of a CCTV camera. Several of these features are described below.

Sun Shields–Exposure to high temperatures may adversely affect the life of the camera. Sun

shields may be used to protect camera housings from direct sunlight, reducing the heat load on

the camera and lens components.

CCTV Technology Handbook

Wipers–Some camera housings employ a wiper, similar to a vehicle windshield wiper, to keep

the optical window of the housing clean. However, many experts dispute the effectiveness of

wipers and recommend simply waxing the optical window periodically. The use of a wiper can

cause debris to erode the optical surface. Wipers also add to the maintenance requirements.

Rubber wiper blades must be replaced periodically, and washer fluid reservoirs must be kept

filled. Some systems use a durable film stretched over the optical surface of the housing. The

film can be advanced from a cartridge to provide a clean optical path.

Heaters and Ventilators–Temperature differences between the interior and exterior of the

camera housing may cause fogging, moisture problems, and icing. Therefore, certain camera

housings may require additional hardware or capabilities to ensure the camera can operate under

extreme conditions. Heaters and ventilators are often used to address environmental issues with

cameras, although the need for additional electrical power increases the operational costs.

Regular cleaning and maintenance can prevent problems with heated or ventilated camera

housings.

3.3.3 Indoor Camera Mounts

The wide variety of CCTV mounting hardware and support equipment enables a security

professional to tailor equipment capabilities to system performance requirements. Hardware

options may become limited with an increase in specific requirements.

A camera can be mounted to a physical structure such as a wall or ceiling but may require

different hardware for each application. Cameras come in many shapes and sizes and the

mounting method can vary depending on the application and performance requirements. For

example, a lipstick camera, often used for covert surveillance, can be placed in objects such as

toys, clocks, or lights. In contrast, a nonfunctioning camera, often referred to as a “drone” or

“dummy,” is simply mounted in a conspicuous location to deter unwanted activity.

Wall Mounts–Wall mounts use a bracket to support the camera similar to a shelf’s bracket. This

mount often provides a method for adjusting the camera’s view or aim.

Pendant Mounts–Pendant mounts can be used to suspend the camera or equipment from a

ceiling.

Corner Mounts–Corner mounts are used to attach a camera at a location where two walls meet

at a right angle. There are two types of corner mounts: inner and outer. Corner mounts are often

located near the ceiling to provide the best FOV.

Indoor Dome Camera Mounts–Dome mounts are sometimes mounted in highly visible areas.

Domes can be partially recessed into a ceiling or mounted flush to a surface. Additionally, a

dome unit can provide a platform for a PTZ camera or multiple fixed camera units. Finally,

dome units should be located and installed with care to account for potential vibrations from

nearby air conditioning and other electromechanical equipment.

3.3.4 Outdoor Camera Mounts

A variety of hardware is available to support and protect sensitive CCTV equipment from

weather and the elements. Many of the same indoor mounting configurations are used for

outdoor applications. Special mounting hardware is often required to match the styles and

aesthetics of the exterior structures’ existing trim elements. The mount/bracket should

CCTV Technology Handbook

accommodate the weight of the camera and housing. If using the camera outside, plastic fixtures

should be avoided because of their tendency to deteriorate and become brittle when exposed to

sunlight. In addition, brackets should be selected that allow for easy repositioning either with

knobs or adjustable arms. This will allow for the flexibility to position and adjust the camera to

improve the FOV. Two outdoor mounting options are detailed in this section.

Pole Mounts–Pole mounts can be used to raise the

elevation of cameras and provide an unobstructed FOV.

Often, the stability of the camera on a pole mount is

sacrificed for height. Wind-induced movement of the

mount may become more noticeable as the camera’s

height increases. Poles should be heavy duty, galvanized

metal and must be completely stable. Pole mounts

typically have stainless steel spring clamps for fastening

to a variety of poles. Placement of the camera needs to

be high enough to prevent tampering, while positioned

appropriately for the intended FOV.

Figure 3-13. Camera on Pan-Tilt

Head with a Pole Mount

Corner Mounts–Corner mounts can be used for fixed or PTZ cameras, but are particularly

helpful for PTZ cameras that need a large viewing angle as they pan through an area. Whenever

mounts are located on or near the top of a building, the presence of adjacent air conditioning or

other vibrating equipment should be noted as a potential source of blurring. Corner mounting

brackets not only need to be secure and provide support for the camera, they must also comply

with building codes.

3.4 Video Monitors

The function of monitors is to display video images for viewing. The selection of monitors is as

important to the quality of the image as the selection of cameras, lenses, and other components in

the imaging chain. The video monitor market offers a number of choices, such as liquid crystal

displays (LCDs) and LED displays, various sizes, and other features. The requirements of the

system will determine the type of monitor for each application. This section details some of the

many features and considerations for monitor selection.

3.4.1 Pixels

The display resolution of a monitor is expressed by the number of pixels that can be displayed.

To ensure the highest quality image, a monitor should be able to show at least as many pixels of

information as the cameras are capable of imaging. Image quality depends on specifications and

adjustments, usually described as width by height using the number of pixels. For example, an

800 x 600 pixel setting on a 17- to 19-inch monitor will provide a mid-range level of video

quality. A 16:9 aspect ratio (width of 16 units and height of 9) has become a standard high

definition television (HDTV) format for displaying wide screen images on televisions and

computer monitors. CCTV systems using digital or IP network components exclusively may

benefit from 16:9 monitors.

3.4.2 Size

Size is an important consideration when selecting a monitor and is always expressed as a

diagonal measurement. Typically, it is difficult to focus a camera using a monitor with a screen

CCTV Technology Handbook

smaller than 9 inches. A 9-inch monitor may be sufficient if the operator is sitting directly in

front of it; however, a 15-inch monitor is the smallest that should be used if multiple images will

be shown on it.

3.4.3 Monitors

This section describes various types of monitors that are available on the market to meet an

organization’s CCTV needs. Summaries of the advantages and disadvantages of each monitor

type can be found in Table 3-3. Table 3-4 provides an overview of video signal display types

used in CCTV systems.

Televisions–HDTVs can be used to view video in certain circumstances such as viewing video

for investigation purposes from a secured office. Televisions can also offer a cost-effective

alternative for dual purpose monitoring of both internal CCTV feeds and network broadcasts.

However, televisions do not have the same durability as monitors; therefore, it is not an

advisable choice for 24-hour monitoring requirements.

PC Monitors–DVRs can be connected to a PC monitor. Inputs and outputs between these

devices need to be matched using standard connectors, adapters, or converters.

Monochrome Monitors–Due to the differences in technologies, monochrome monitors have a

greater potential to display detail than color monitors. Although the difference in resolution of

color and monochrome monitors is narrowing, the potential loss of visual detail with a color

monitor must be weighed against the cost and benefits of its display. Either type of monitor can

display both monochrome and color video signals.

CCTV Monitors–Monitors designed for CCTV systems are preferred if the system will include

multiple monitors and cameras, or if the monitor is always on. Monitor technologies include

cathode ray tube (CRT), LCD, organic light-emitting diode (OLED), and plasma.

CRT Monitors–The CRT analog monitor is a legacy CCTV monitoring

technology. CRT monitors are available in a variety of sizes. CRT

monitors should include electromagnetic interference (EMI) protection.

EMI can distort the path of the electron beams and reduce the quality of

the image. Since CRT monitors are bulky, they are no longer used in

handheld viewing devices and are seldom used in other configurations of

portable equipment. Figure 3-14.

CRT Monitor

LCD Monitors–LCD monitors are available in many shapes, sizes, and

resolutions. They provide a sharper, brighter picture than CRT monitors because they can

process CCTV signals at a higher resolution. LCD monitors are much thinner front-to-back than

CRT monitors of similar screen size so they take up less space and they generate less heat.

Many are small and compact enough to be portable. They are also available in large sizes for

multiple camera viewing. An important advantage of LCD monitors over CRT monitors is that

LCD monitors do not suffer from magnetic interference. LCD monitors are being incorporated

into many monitoring facilities in government, industrial, and corporate installations and provide

more flexible viewing options than can be achieved by using banks of CRT monitors.

OLED Monitors–LED/OLED monitors use OLEDs, which emit light directly without the need

for a backlight. This means that each diode can be turned on and off depending on what needs to

be displayed on the monitor screen, unlike LCD displays, which require the backlight source to

CCTV Technology Handbook

be covered to produce blacks. The OLED implementation results in better contrast as well as

reduced power consumption compared to LCD monitors. However, OLED display technology is

more expensive, more difficult to produce, and has a shorter lifetime than LCD monitors.

Plasma Monitors–Plasma monitors are much like LCD monitors in that they are flat panels and

individually control every pixel. A plasma display has a specific gas inside every pixel. The

pixel elements illuminate in response to received electrical signals. Plasma monitors are

available in many different sizes, although most are manufactured in a wide-screen 16:9 aspect

ratio. The main advantage of plasma over LCD monitors is the greater viewing capability from

an off-axis angle. Plasma displays are rapidly becoming less popular in CCTV applications due

to improvements in LCD display capabilities.

Table 3-3. CCTV Monitor Technology Comparisons

Type Pros Cons*

CRT

• Good overall picture quality

• Robust technology

• Low-cost option that is compatible with

most existing CCTV equipment

• High power consumption

• High heat generation

• High space requirements

• Manufacturers have largely

discontinued

• Burn-in tendency (when consistent

image is permanently etched onto

screen)

LCD

• Compact and relatively light

• Low power consumption and

electromagnetic radiation

• Wide range of screen sizes available

• No flicker

• Less burn-in. Long life expectancy (up

to 50,000 hours)

• Limitations reproducing true black

colors

• Restricted viewing angle

• Low image contrast

• Time lag of pixels can lead to

“smearing” effect

OLED

• Thinner, lightweight, low-power

consumption, and better dynamic

contrast ratio

• Brighter display and wide color range

• More expensive than other monitor

technologies

• Shorter lifespan

Plasma

• Wider viewing angles than LCD

• Higher black levels

• Higher contrast ratio (the difference

between the brightest and the darkest

part of the image)

• Fragile

• High power consumption

• High heat generation

• Susceptible to burn-in

*Many of the disadvantages listed are being addressed by the industry in newer products.

CCTV Technology Handbook

Table 3-4. Video Transmission Signal Display Types

Video

Transmission

Signal

Analog Digital Digital Digital Digital

Signal Type NTSC

Standard

Definition

Standard

Definition

High

Definition

High

Definition

Video Quality

Standard

Good Pictur

e Better Picture

Best Possible

Picture

Best Possible

Picture

Aspect Ratio 4:3 4:3 4:3 or 16:9 16:

9 16:9

Maximum

Resolution

(Dig

ital Pixels)

480i

(480x640)

480p

(480x704)

720p

(720x1080)

1080i/1080p

(1080x1920)

Notes:

NTSC–National Television Standards Committee

Interlaced Picture (i)–each frame of video is sent or displayed in two fields, all odd lines are shown

first then all even lines, to create a single picture frame. Video consists of an image being created

and displayed 24, 30, or 60 times a second.

Progressive Scan (p)–non-interlaced, scanning all the horizontal lines in one pass to create a single

picture frame. Video consists of an image being created and displayed 24, 30, or 60 times a second.

3.4.4 Video Walls

Monitoring facilities may be designed with a wall of screens placed in close proximity to each

other to display video, maps, facility diagrams, alarm points, access control, event logs, third

party applications, and Internet websites. If the monitoring center will be used for other

purposes such as an emergency operations center or for training, presentations, or video

conferencing, it is important to make sure all requirements for use are clearly understood and

identified early in the selection process. Video walls may use rear-projection monitors, thin film

transistor (TFT)-LCD monitors, front projection LED tiles, or HD LCD displays. Video walls

are controlled by a video wall processor, a type of video switcher, which accepts multiple inputs

and processes those inputs for display on multiple monitors simultaneously.

Rear Projection Monitors–Two types of display technologies, CRT and micro-display, are used

in rear-projection monitors: Micro-displays are segmented into digital light processors (DLPs),

liquid crystal on silicon (LCoS), and LCD-driven displays. Rear-projection units can accept both

analog and digital inputs with different image sizes. Projection technology requires lamps to

create images and those lamps will burn out over time. Also, the lamps create heat and need to

be cooled by fans, which require filtered air. For these reasons, it is important to factor in the

maintenance and replacement costs for bulbs and filters. A comparison of monitor types is

shown in Table 3-5.

CCTV Technology Handbook

Table 3-5. Rear-Projection Monitor Comparisons

Type Pros Cons

CRT

• Good level of performance with black

colors

• Greater space requirements

• Require periodic maintenance and

adjustments

• Narrow viewing angle

• Dim picture in bright settings

DLP

• True black colors with sharp picture

• Can receive HDTV signals

• Thinner and lighter than CRTs

• Do not require periodic adjustments

• Require periodic lamp replacement

• More susceptible to low-level noise

resulting in a display issue known as

dancing pixels

• High contrast video can also result

in a rainbow effect being displayed

LCD

• Slightly better color reproduction than

DLPs

• Do not require periodic adjustments

• Resolution is as good as or slightly better

than DLPs

• Lower level of performance with

black colors (improving with new

products)

• Require periodic lamp replacement

LCoS

• Higher resolution than other

rear-projection units

• Some manufacturers have discontinued

production

• Color and black-and-white

reproduction need improvement

• Require periodic lamp replacement

• Expensive technology

TFT-LCD Monitors–These flat video screens are considered superior to the classic LCD

monitors. Their color quality, fast response time, and high resolution contribute to high quality

video imaging. TFT-LCD walls can be used as one large screen or divided into smaller screen

combinations to display different images simultaneously.

Front Projection Monitors: LED Tiles–Newer technology options include LED tiles to

produce a control room display as shown in Figure 3-15. LED tiles offer minimal gaps between

panels and help manage video images that span several screens with displays that offer fine

details. Options are available for tiles with or without borders, depending on viewing needs.

LED components have an extended life expectancy rated up to 65,000 hours at half brightness,

improving the replacement frequency to 7 years or more. Generally speaking, LED technology

is lighter, sharper, brighter, more energy-efficient, and less expensive to manufacture than TFT

monitors. An integrated LED tile wall allows for greater flexibility by enabling images from a

single source to be wrapped across multiple screens or to display separate image sources on each

tile. LED tile monitors are currently an expensive option but usually require less maintenance

than earlier types of monitors.

CCTV Technology Handbook

Figure 3-15. LED Tiles

HD LCD Displays–Multiple displays can be created by grouping and configuring clusters of

LCD monitors on a wall like tiles. In the past, the most prevalent problem with HD LCD

displays was related to burn-in. The current technology uses a method in which the image is

moved so slightly that it is imperceptible to the human eye and prevents burn-in.

3.5 Switchers and Multiplexers

In CCTV systems that have more cameras than monitors and recording devices, switchers and

multiplexers are used to route the video signal. Switchers are simpler in concept than

multiplexers. They can be set manually or automatically to send analog or digital video to a

monitor or a recorder. Some switchers can send frames or fields from several cameras to a

recorder in a sequential manner, recording a frame or field from each camera in sequence.

Multiplexers, invented in the 1980s, have capabilities not available in switchers. Multiplexers

receive the analog video from several cameras and digitize the signal. Multiplexers can be

programmed to prioritize the video from the different cameras according to rules. Cameras

covering alarmed areas in an integrated security system may be prioritized so that their images

are shown on a monitor and all frames recorded. Many multiplexers have imbedded motion

detection and analysis software to support the recording or displaying of an image only when the

software detects movement or some other phenomenon.

Many multiplexers can be used in networks controlled by computer systems. This flexibility,

when combined with digital storage media instead of tape storage systems, blurs the distinction

between multiplexers and other components like digital video recorders (DVRs) and network

video recorders (NVRs). DVRs and NVRs not only perform the functions of multiplexers, but

also include integral hard drive storage so that video is recorded as compressed digital data.

Section 3.6 provides additional information on DVRs and NVRs.

Fully digital video systems, using network cameras, do not use switchers or multiplexers. The

cameras send compressed digital video data directly to DVRs, or to monitors, over an Ethernet or

CCTV Technology Handbook

other electronic data network. Digital imaging and digital storage devices are becoming

standard, but switchers and multiplexers offer a low cost, easy-to-use alternative.

The primary advantage of using switchers and multiplexers in analog CCTV systems is the

ability to route the video signal to multiple output devices. Section 4 addresses transmission and

storage of video using IP networks. This section on switchers and multiplexers provides

information about more traditional CCTV systems, which may use analog or digital components.

3.5.1 Switchers

Switchers are simpler in concept than multiplexers. They can be set manually or automatically

to send analog video or a TV signal to a monitor or a recorder. Some switchers can send images

from several cameras to a recorder in a sequential manner, recording an image from each camera

in sequence.

Selecting the proper switcher largely depends on the number of cameras and monitors used and

how the monitors will display the video. The simplest and most common devices used for small

CCTV systems are the manual and sequential switcher. Most switchers provide a means to

expand the CCTV system as new requirements are identified.

Figure 3-16.

Microprocessor-Based

Switcher

As CCTV systems are built with greater n

umbers of came

ras and

monitors, switchers have become more powerful and versatile.

Microprocessor-based switchers have a host of features such as:

• Camera and lens control;

• On-screen text;

• Password protection for programming;

• Partitioning of video for selected users;

• Interface capabilities with additional alarm and relay

panels;

• Remote viewing and control over IP networks;

• Macro programming and event timers;

• Integrated color bar generators for setting up monitors; and

• Networking for several switchers.

CCTV systems with large numbers of components need

microprocessor-based switchers that can handle large

numbers of video inputs and outputs. These are referred

to as matrix switchers.

Matrix switchers offer versatility and some can handle

over 4,000 cameras and 500 monitors. These switchers

have the ability to control cameras, preset positions, or

pan in the event of an alarm. Software programs have

been developed to handle all types of camera, monitor,

and recording situations. For example, user profiles and

priorities can be created for as many as 100 operators

and security personnel.

Figure 3-17. Monitoring Station

with Matrix Switcher

Matrix switchers can often be preprogrammed at the facto

ry to suit a client’s specifications,

which will save considerable installation time. The ability to upgrade software and the

CCTV Technology Handbook

availability of built-in diagnostics for the hardware are also important features in selecting

equipment.

3.5.2 Multiplexers

Multiplexing began the transition from analog to digital video;

these devices receive an analog video signal and then digitize it.

Unlike switchers, which do not digitize the video signal,

multiplexers often have imbedded software that can perform

analytical tasks on the video signal, such as video motion

detection. Before transmitting video data to other components, a

multiplexer may convert the signal back to analog for display or

recording.

Figure 3-18. Multiplexers

Multiplexers are designed to record frames, images, or fields. Security personnel can program

multiplexers to prioritize the video from the different cameras according to rules. Cameras

covering alarmed areas in an integrated security system may be prioritized so that their images

are shown on a monitor and all images are recorded. Some multiplexers have imbedded motion

detection and analysis software to record or display the image only when the software detects

movement or some other phenomenon.

A number of multiplexers can be used in networks controlled by computers and servers. This

flexibility, when combined with digital storage media, blurs the distinction between multiplexers

and DVRs. DVRs not only perform the functions of multiplexers, but also include integral hard

drive storage so that prioritized video is recorded as compressed digital data.

3.5.3 Multiplexer Networks

Multiplexers can be linked together using a multiplexer server to create systems capable of

handling greater numbers of video input sources and outputs to monitors and recorders. Linking

multiplexers enables the operation of a complete system with several video monitors. These

networks can be programmed to perform complex sequencing.

The ability to network multiplexers brings the capability closer to that of the DVR by combining

a multiplexer server with multiplexers and adding a hard drive. It is prudent to carefully

consider the cost of multiplexers and associated components before discounting the purchase of a

DVR.

3.6 Video Recorders

Recording capability is essential for assessment, investigation, and evidence collection. Video

recording has transformed from tape-based systems to digital hard drive systems. While some

systems still use tape, the popularity of digital video has driven the demand for recorders with

hard drive storage. Traditional analog CCTV systems in which video is recorded to video

cassette recorders (VCR) are rare in today’s environment and have rapidly been taken over by

DVRs and NVRs on IP networks. Many types of recorders are being used today, but this section

will focus on digital recording equipment as well as removable media and some emerging

technologies.

CCTV Technology Handbook

3.6.1 Digital Video Recorders

A CCTV system may send digital or analog video to the recording system. A DVR receiving

analog video takes two fields of the analog signal and builds one image, which is then digitized

and compressed. If the video going to the DVR is digital, it is normally compressed to save

storage space. Various data compression methods can be used that offer varying degrees of

performance, quality, and storage economy.

DVRs can include a variety of features and capabilities such as:

• On-board software, such as video analytics;

• Image protection/authentication techniques;

• Ports for additional recording capabilities;

• Internal hard drive for video storage;

• Ability to easily search for and locate events;

• Ability to record one or more camera inputs while performing video analytics;

• Removable hard drive for archiving purposes; and

• Ability to transfer data to expandable storage systems called Redundant Array of

Independent Disks (RAID) to free up recording space.

DVRs may be classified as simplex, duplex, or triplex. Simplex DVRs cannot record while

searching and viewing recorded images. Duplex systems can record while searching. Triplex

DVR systems allow the operator to view recorded and live video while recording continues.

Recording Capacity–Many components of a CCTV system need to be integrated and

configured according to other device settings. For example, the method in which the system’s

cameras capture images will influence the amount of data the DVR needs to record and retain.

Two important determinations include the frame/image size and the frames/images per second.

Frame/Image Size–This value is the average size of each image as recorded. The actual figure

will be a function of the image resolution (in pixels or TV lines) and the amount and type of

compression applied to the image or video sequence.

Frames/Images Per Second (fps and ips)–The number of frames/images recorded each second

by a camera has a significant impact on the amount of data being generated. The preferred frame

rate should be determined in the design phase. The fps or ips value can be dynamic if a camera

is triggered by external alarms or motion detection. Some systems may be configured to record

only when activity is detected. Other systems may provide continuous recording at a low image

rate (e.g., 1 ips) until activity is detected. The system then records at a higher image rate

(e.g., 12 ips) for a specified period of time.

Recording Strategies–Organizations may find it beneficial to customize the recording settings

for various cameras. For example, the recording rates set for primary cameras (i.e., those that are

viewed most frequently) may be set at a higher rate to allow quality viewing of movement. In

contrast, the default setting for secondary cameras (i.e., those that are focused on less critical

areas) could be set at a lower rate.

CCTV Technology Handbook

3.6.2 Data Compression Methods

The type of compression selected dictates the quality and amount of video data that can be stored

on a DVR. Therefore, it is important to understand the differences in compression technologies.

The compression aggressiveness affects how much video data can be stored on a hard drive

recorder and the quality of the images during playback. If the compression is too aggressive and

too many pixels are removed, faces or objects may not be recognizable.

The following example illustrates the amount of video data that accumulates over time and why

compression techniques are important. A DVR will require the following storage capacity for 2

hours of uncompressed data (1 megabyte [MB] of data per image).

1 MB of data x 30 images per second

x 60 seconds

x 60 minutes

x 2 hours

=216,000 MB or 216 gigabytes (GBs)

This data storage requirement can quickly overwhelm the hard drive space of a DVR, especially

when multiple cameras are being used. The number of images per second can be reduced to

allow a smaller storage requirement, but the example above provides a good illustration of why

compression techniques are needed.

Most organizations’ DVRs serve a dual purpose: 1) high quality video recording and 2) live

surveillance viewing as transmitted through the Internet or other data distribution means. This

creates a dilemma in which high quality recording requires high data rates, which in turn can be

problematic for efficient and fast transmission of data. If the data is compressed to accommodate

faster transmission, the video quality and resolution will suffer.

Traditional compression technologies include: Joint Photographic Experts Group (JPEG),

JPEG2000, Moving Picture Experts Group (MPEG)-1, MPEG-2, MPEG-4, and Motion Joint

Photographic Experts Group (MJPEG). These traditional video coders compress the incoming

analog video signal (input) and produce a single digital video signal (output). DVRs then use

this single digital output for recording and transmission of video, thus resulting in the trade-off

between data size, resolution, and quality.

Another data compression technology is a multi-rate video coder, or scalable motion adaptive

coder-multi-stream (SMAC-M). SMAC-M is a proprietary video compression technique that

enables multiple data output streams to meet different video recording and viewing needs.

The latest video compression standard, H.264/MPEG-4 Part 10 advanced video coding (AVC), is

currently the most commonly used format. H.264 is best known as the codec standard for

Blu-ray Discs

™

and is widely used by streaming Internet sources such as YouTube

™

, iTunes

Music Store

, Adobe

Flash

Player, and many more. H.264 requires half the bandwidth of

other standards and allows for more effective compression, while also providing better quality,

flexibility, and a variety of features such as multi-picture/inter-picture prediction and variable

block size motion compensation.

Users must tailor the compression method to their needs, the surveillance environment, and

objects being observed. First, the proper compression format should be selected, followed by the

resolution setting. This process should allow system specialists to determine if adequate hard

drive space is available.

CCTV Technology Handbook

3.6.3 Hard Drive Recorders

Standard rack-mount, hard drive recorders are generally mounted in a 19-inch rack system and

may receive a number of analog video inputs: 4-, 8-, 12-, 16-, and 32-input units are typical.

These units can be switched between the NTSC and phase alternating line (PAL) video standards

and have power supplies that accept a 60-Hz or 50-Hz current.

The hard drive capacity is a key specification for systems without a network storage strategy,

since the device hard drive will determine how many days of recording remain before the system

begins recording over the oldest video. The data storage requirements will depend on the type of

cameras connected to the DVR. The resolution, image rate, motion detection features,

complexity of image, and FOV will also affect the unit’s storage availability.

Figure 3-19. Hard Drive

Recorder for 19-inch Rack

Most hard drive recorder models have the following features:

• Multiple hard drives;

• Built-in compact disk rewritable (CD-RW) or digital

versatile disk (DVD) that provides permanent

recording on removable media;

• Alarm inputs to trigger event recording; and

• Multiple analog monitor outputs, usually up to four.

3.6.4 Other Recording Options

Network Video Recorder–NVRs record digital video data transmitted over an IP network from

multiple CCTV digital cameras. NVRs can be configured to record video in a digital format to a

disk drive, portable storage device or a mass storage device. NVRs differ from DVRs as video

input is delivered from an IP network. With an NVR configuration, video is encoded and

processed at the camera and streamed to the NVR for storage or remote viewing. With a DVR

configuration, video is encoded and processed at the DVR.

Hybrid DVR–Hybrid DVRs incorporate functions of both NVRs and DVRs by accepting and

converting video images from analog cameras as well as IP video inputs. Hybrid DVRs often

have IP connectivity supporting remote viewing capabilities to play back recorded video from

across the network. They also allow viewing of live video.

Mobile Recorders–Mobile recorders are replacing mobile VCRs in patrol cars and on

motorcycles. Mobile recorders have all the features available in a conventional DVR and are

less susceptible to dirt. These recorders have become reliable recording platforms due to the

advancements in immunity to vibration and motion. Many mobile recorders provide the ability

to download recorded data to a memory card.

Some mobile recorders have a removable hard drive for data backup. Some also have wireless

inputs and outputs for transmitting the data to a server. Mobile recorders are often coupled with

other devices, such as radar guns, where the radar information is overlaid on the video itself.

3.6.5 Portable Storage Devices

DVRs can accommodate several types of portable storage media. Universal serial bus (USB)

flash drives, memory sticks, and DVD+R dual layer (DL) are detailed below.

CCTV Technology Handbook

USB Flash Drives–USB flash drives allow video to be recorded or transferred. USB flash

drives are available in capacities in excess of 128 GB, have a fast transfer speed, and can be

programmed with password protection.

Memory Sticks–Memory sticks come in a variety of capacities up to 1 terabyte (TB). They

have a fast transfer rate allowing video to be transferred to them quickly.

DVD+R DL–DVD+R DL discs have two storage layers and can hold about 17 GB of data.

There are also other DVD media available, including DVD-R, DVD-RW, DVD+R, DVD+RW,

and DVD-RAM. These are lower in cost but hold less data (approximately 4.9GBs).

3.6.6 Video Motion Detection

Motion detection can be built into the DVR software or directly into the camera. Video motion

detection software analyzes video images frame by frame, and when a frame to frame change is

detected, the CCTV system can alert the operator. In some cases motion detection can start DVR

recording. The sensitivity of motion detection can be adjusted to reduce false triggers. The more

sophisticated systems allow the user to define areas where motion can be ignored, such as

movement of a ceiling fan or a tree branch moving in the wind. Other advanced features are

available, such as object left behind and missing object detection. For more information on

video analytics, see Section 6, as well as the Video Analytics Systems Market Survey Report

available in the SAVER section of the DHS S&T website.

TRANSMISSION

The transmission system is an important component of the CCTV imaging chain that sends and

receives video signals between the cameras, the processing system (i.e., DVRs, NVRs, and

multiplexers) and the monitoring system (i.e. the display). Transmitting a strong video signal

with low noise is vital to producing a high-quality image on the monitor. Many problems

associated with the quality of a CCTV system signal are attributable to the transmission system.

Many types of video transmission technologies are available today. High-quality components

are needed to produce a high-quality result. The distance between a camera, monitor, and

storage system is one of the most important criteria for deciding which means of transmission to

use. IP-based systems are quickly gaining popularity as digital formats are becoming more

common within CCTV systems. Other selection factors include installation costs, existing

infrastructure, and availability of power. The options described below are available when

determining the best suited transmission strategy. Any copper conductor (coaxial cable, twisted

pair, etc.) exposed to an outdoor environment is susceptible to noise and lightning strikes.

Lightning protection is an essential added expense and could degrade the video transmission if

improperly installed and maintained.

4.1 Wired Transmission

Wired CCTV systems use cables to connect cameras to other CCTV components. Wired

transmission can provide good quality video images with fewer instances of interference because

cables are shielded. Cameras can be located far away from recording or monitoring equipment.

Three types of wired CCTV systems are commonly used today: coaxial cables, UTP cables, and

fiber optic cables. Transmission over a public telephone network is not advisable for CCTV

CCTV Technology Handbook

transmission due to the cyber security issues related to an open network; however, it is still used

in some CCTV environments.

4.1.1 Coaxial Cable

Coaxial cable is the most common method of transmitting video signals from the camera to the

monitor or other CCTV components. Coaxial cable consists of a single wire surrounded first by

a nonconductive insulating layer (dielectric), then by a braided wire shield, and finally a plastic

or rubber covering. This construction is shown in Figure 4-1. Note that CCTV applications

require cable of the highest quality materials and manufacture. Both the center conductor and

the braided shield must be copper. Aluminum foil-wrap shield, which is used in some consumer

cable applications, does not meet CCTV requirements.

Direct-run distances of up to 2,000 feet can be achieved, depending on the gauge of the cable.

Cable runs across greater distances are possible, although this requires the use of amplifiers

inserted in the line between the camera and monitor.

Poor quality cable can have a negative impact on reliability and image quality. As transmission

through coaxial cable is electrical, it is susceptible to Radio Frequency Interference (RFI) and

EMI. It is possible for unauthorized persons to acquire the video signal either through these

emissions or by directly tapping into the cable.

Care should be taken to properly ground the entire CCTV system when using coaxial cable or

any other form of electrical signal transmission. Improperly grounded devices and cabling can

result in poor quality video, loss of video, or a grainy image.

Figure 4-1. Coaxial Cable Construction

4.1.2 UTP Wire

In some cases, running coaxial from a camera to a monitoring location is not practical and

existing telephone wire can be used. For example, many buildings contain abandoned telephone

lines, known as UTP, which can be used for a video system. This has several advantages: overall

cost savings, low susceptibility to EMI or induction, no ground loop concerns, and ease of use.

Also, telephone wire is smaller and much lighter than coaxial cable. It should be noted that

using abandoned telephone wire beyond a facility’s boundaries may require an approval process

and service agreement with the telephone company.

UTP is comprised of two wires, twisted together. They are most often 22 or 24 American wire

gauge (AWG) in size. When considering twisted pair for video transmission, unshielded twisted

CCTV Technology Handbook

pair should be used to connect only one camera to a monitor or other device. Twisted pair must

be dedicated solely to a particular video camera. While the per foot cost of twisted pair wire is

lower than coaxial cable, signal conversion devices (transmitter and receiver) are required at

either end of the wire run. Twisted pair wire can be used in runs of up to 5,000 feet. By using

repeaters at least every 4,500 feet, twisted pair can be used over greater distances.

UTP, like other electrical transmission mediums, may be susceptible to various forms of

interference and unauthorized acquisition of the signal. Performance is compromised when

wires are routed through a telephone switching station. This type of wire should be used for

continuous point-to-point transmission and routed through “punch down blocks” or splices. The

connections should have solid, zero-resistance connections.

4.1.3 Fiber Optics

Fiber optic cable is lightweight and made up of a single spun glass or plastic fiber or a group of

such fibers encased in a protective covering. It has a broad bandwidth, making it ideal for

carrying video signals. Fiber optic cable can be used in runs up to 6 miles without amplification.

The video signal coming from the camera must first go through a fiber transmitter which

converts electrical signals to light impulses. A fiber receiver at the other end is required for

conversion back into electrical signals.

Fiber optic cable is immune to RFI and EMI. In addition, grounding is not an issue with fiber

optics and the cable is less susceptible, if not immune, to lightning strikes. Furthermore, in

systems designed with top-of-the-line components, fiber optic cable has high cost to performance

ratios. A single strand of single mode fiber can carry 32 channels of analog video. In low-end

systems, the expense of fiber optic cable may not be warranted. Fiber optic cable requires

extremely precise installation as the most minor damage to the cable or sharp bends can cause a

major degradation of the signal.

4.1.4 Telephone Network

Another option for wired transmission of video signals is the telephone network. Although

standard voice grade telephone lines do not have enough capacity to handle real-time full motion

video, they still have value in specialized CCTV applications. However, telephone lines are not

recommended when the security of the video is a concern due to the cyber security

vulnerabilities. An example can be seen in Figure 4-2.

Figure 4-2. Telephone Network Example

CCTV Technology Handbook

Some CCTV systems utilize slow-scan video imaging. Instead of using the standard 30 frames

or images per second, slow scan video selectively skips images. In addition, each image may be

a lower resolution than standard video. Digital compression can improve this transmission

method considerably.

Ongoing improvements to compression technology have made it possible to send video images

more efficiently across the telephone network. Currently, one video image can be transmitted

every 6 to 12 seconds over standard phone lines at 28.8 kilobits per second (Kbps).

Integrated services digital network (ISDN) phone lines have a higher bandwidth because they

combine two 56 Kbps channels for a total transmission speed of 112 Kbps. This high speed data

transfer rate allows one video image to be transmitted in approximately one second.

Other high speed options are available, including T-1 or Fractional T-1 lines. The T-1 family of

technologies allows for multiple 56 Kbps channels to be combined, thereby achieving larger

bandwidths. Very large bandwidth lines, such as T-3 or E-1 lines, may be suitable for very large

CCTV systems.

4.1.5 Category 5 Cable

Networks transmit video over Category 5 cable. The cable consists of four pairs of UTP

24-gauge copper wire with three twists per inch. The high number of twists per inch reduces the

“crosstalk,” or EMI, between signals passing on the strands of the cable. Category 5 cables can

be used to carry frequencies of up to 100 megahertz (MHz) and handle data rates up to 1,000

megabits per second (Mbps). The cables are terminated with an RJ45 connector and must meet

the Electronics Industry Alliance/Technology Industry Association 568 Commercial Building

Telecommunications wiring standard.

4.2 Wireless Transmission

Wireless options for transmitting video can be advantageous due to ease of installation, lack of

cabling requirements, and assured mobility. There are some disadvantages of wireless systems

such as the need for a dedicated frequency to transmit signals, signal interruptions, and signal

interference. There are also increasing concerns over cyber security and the need for information

assurance hardening. Wireless transmission options for CCTV systems are discussed below.

4.2.1 Laser

In some applications, it is impractical to install video transmission cables. If there is a direct

line-of-sight between the transmitting and the receiving locations, laser or IR transmission may

be used.

Applications for laser transmission versus wired transmission offer several advantages. Laser

transmission systems offer the following features:

• Transmission over distances of 20 meters to 2 kilometers in clear weather;

• Data speeds from 25 MB to 1.2 GB;

• Handling of misalignments of 2.4 degrees horizontally and vertically (particularly

useful for tall buildings or towers that sway in the wind);

• Indoor mounting applications that can be placed behind a glass window;

CCTV Technology Handbook

• International Electrotechnical Commission Class 1M safe (can be safely viewed by the

naked eye);

• No ground loop, lightning, or induction issues;

• No license or permit requirements; and

• Difficult to tap into without being detected.

Lasers also have disadvantages. Lasers should not be placed in areas with human activity to

prevent possible retinal injury. In addition, laser transmission is affected by weather, a factor

that influences the feasible distance between the transmitter and the receiver. Line of sight and

alignment of the signal is critical. Recent technological advances have included a narrow beam

and auto tracking capabilities that tolerates fog and snow better than older laser systems. While

there is always the possibility of momentary disruption, retransmission can automatically occur.

4.2.2 Infrared

An alternative to laser transmitters is an IR LED transmitter. IR LED systems may cost less than

laser systems, but they often have shorter transmission distances and lower bandwidth. LED

systems are also more susceptible to reflections when transmitting through glass. IR receivers

should not be oriented so that they face the sun, incandescent light bulbs, or other IR light

sources. When considering an IR LED transmission system, it is important to clearly understand

the application and installation constraints.

4.2.3 Radio Frequency

Radio frequency (RF) is another method of wireless transmission relevant to CCTV surveillance.

RF modulation of video signals is used in cable TV systems with ultra high frequency (UHF) and

very high frequency (VHF) bands. RF encompasses a broad range of frequencies.

Transmissions are typically focused beams, which are most efficient in open-air, line-of-sight

situations. Physical obstructions such as walls or buildings are likely to degrade an RF video

signal.

A typical CCTV RF system may:

• Operate on 2.4 to 5.8 GHz bands;

• Interface with 802.11 access points so that software can be upgraded via a network;

• Require Federal Communications Commission (FCC) licensing;

• Include video compression; and

• Include remote device/sensor control.

RF systems are often used when a cable installation or lease of a high-bandwidth line is

impractical. Limited range is a common misperception regarding RF transmission systems. In

fact, RF CCTV transmission systems can operate over long distances using directional antennas

and repeaters. RF can transmit approximately 2 miles with a flat antenna array or up to 7 miles

with a directional antenna. Different types of antennas can be seen in Figure 4-3.

CCTV Technology Handbook

Flat Antenna

Array

Omni-

Directional

Antenna

Directional

Antenna

Figure 4-3. Types of Antennas for RF Transmission

RF systems have limited bandwidth, so the number of cameras that can be used simultaneously is

small. If several cameras are transmitting at the same time, the signals should be out of phase

with each other, and ideally any additional antennas should be facing 90 degrees away from each

other.

One of the most prevalent RF video systems in the consumer market is the 5.8-GHz camera and

receiver. However, the system is vulnerable to EMI and provides low-resolution images. There

are other RF devices that can be used for specialized applications, but these devices generally

operate on specially assigned frequencies, which require a specific license.

4.2.4 Microwave

Microwave transmission is a wireless, line-of-sight transmission medium with many similarities

to laser and LED systems. Depending on its specific configuration, a microwave system can

transmit video, audio, and data. Some factors to consider when exploring microwave

transmission are:

• Transmissions from 100 feet to 20 miles are possible, and longer distances can be

achieved with microwave repeaters;

• Microwave transmitters may require FCC licensing;

• Microwave transmission tolerates adverse weather and obstructions better than laser

transmission. However, very heavy rainfall and very dense fog can affect microwave

transmissions;

• Microwave systems emit at low energies, which are typically less than 1 milliwatt per

square centimeter (mW/cm²). In comparison the minimum safe radiation exposure

level established by the American National Standards Institute is 10 mW/cm²; and

• Microwave systems typically are more expensive than LED or laser systems.

Microwaves can pass through glass; therefore, mounting a system indoors to maintain an

aesthetically pleasing building exterior may be feasible. The receiver and transmitter require

careful alignment for optimal results. Since the signal can weaken over a long distance, it is

CCTV Technology Handbook

important to consider the distance and performance requirements carefully in the system design.

Shiny surfaces, such as windows or water that are aligned parallel to the beam, may reflect

energy in the outer portions of the beam toward the receiver and degrade the video signal.

Figure 4-4. Typical Microwave Installation

4.3 IP Network Transmission

IP-based systems have emerged as an attractive alternative to other technologies, due in large

part to their ability to achieve high-performance video capabilities at a low cost. The industry

has found ways to implement IP-based systems that use existing cameras, cables, and other

equipment. However, organizations planning and designing new systems should consider

IP-based technology. This section addresses the basic parameters of an IP-based network

system.

4.3.1 Internet Protocol Network System Overview

IP-based CCTV systems are designed to provide the ability to monitor, record, and stream video

over a network to computers or other equipment. The system can use existing local area

networks (LANs), wide area networks (WANs), and/or wireless LANs (WLANs) to save on

installation costs. However, for added security, an organization could install its own private area

network (PAN) cabling and support hardware. Power over Ethernet (PoE) technology is also an

option within an IP-based system to increase savings and reliability. PoE enables various

networked devices to receive power and data through one standard cable, which can be a

significant cost savings when designing CCTV systems.

A simple IP-based CCTV system, such as the one seen in Figure 4-5, consists of a network

camera (although analog cameras can be used with additional equipment), a network switch, and

a PC for viewing, storing, and analyzing data and managing the CCTV system.

Figure 4-5. IP-Based CCTV System

Traditional analog-based CCTV systems require dedicated point-to-point cabling from each

camera to the recording and/or viewing locations. In an IP-based CCTV system, video is

digitized at the camera and can then be transmitted over the IP network to virtually any location

CCTV Technology Handbook

around the world. Most analog systems are traditionally unidirectional, whereas network based

systems are bidirectional, easier to integrate into larger systems, and highly scalable.

Network cameras and other devices can not only send audio/video, but can also send other data

like text or short message service (SMS) messages to users as well as receive audio and data

(which can activate alarms, door entries, and external alarms). In addition, IP-based systems

have the ability to interface and communicate with multiple parallel applications (e.g., motion

detection or license plate readers).

4.3.2 Benefits of IP-Based Systems

Digital systems in general have a variety of advantages over analog systems such as ease of use,

advanced search capabilities, simultaneous record and playback, improved image quality, and

efficient compression and storage options. IP-based systems also provide many benefits that

include:

• Remote accessibility;

• High image quality;

• Future integration with digital technologies;

• Flexibility;

• Scalability; and

• Cost-effective transmission.

4.3.3 IP-Based System Components

The flexibility of IP-based systems is attributed to the variety of configurations and types of

components compatible with IP technology. Since the number of possible custom configurations

is so vast, the following list is just a sample of the type of components compatible with IP-based

systems.

Cameras–Both IP network cameras and analog cameras can be used in an IP-based system.

Video Encoders–When using analog cameras, a video encoder or video server needs to be

connected to the analog cameras to convert the video to a digital format. The encoder then sends

the data over an IP network.

Network Switches–Switches allow CCTV devices to communicate with each other and share

information.

Networks–A network can be small or extensive, wired or wireless or a combination thereof.

The most common approach taken by organizations is to use LANs or WANs. Network

bandwidth capacity can be increased by adding switches and routers. Wireless networks are a

good option when traditional wired networks are too costly or difficult to install.

Power over Ethernet–PoE is an option for using a wired network to distribute both data and

power.

PC with Web Browser–PCs can access live and recorded video over the Internet as needed.

CCTV Technology Handbook

PC with Video Management Software–PCs can record and store video from cameras, as well

as view live and recorded video as needed. Additionally, video management software can

support video being accessed over smartphones or tablets.

Storage Devices–Video transmitted through an IP system can be stored on a server, a network

device such as direct attached storage (DAS), storage area networks (SAN), network attached

storage (NAS), or a PC hard disk. These storage devices are discussed further in Section 5.

Mobile Devices–IP-based systems can be easily configured to facilitate access to video via the

Internet from smartphones, laptops, and other mobile devices.

4.3.4 Cyber Security

The confidentiality, integrity, and availability of data are critical for any organization. CCTV

systems, especially IP-based systems, present a cyber-security risk because their video images

and critical operational surveillance data is transferred and stored on a network. Protecting

information should be a high priority in security planning.

Cyber security is a large and complex issue that extends far beyond the implications of a CCTV

system. However, issues such as hardware and software control measures, network control

measures, and network security should be considered by any agency incorporating an IP-based

CCTV system.

5. VIDEO STORAGE

A CCTV system needs to be designed and configured so that it retains the necessary quantity and

quality of video data. CCTV systems must also be equipped with appropriate export and

archiving capabilities. An organization must clearly determine the purpose of the video that is

being collected and understand how it may be used. Equally important is establishing the image

resolution, image rate, and the number of days of recording that will be stored by the system.

These factors will influence the use, access, recall, and storage requirements of a CCTV system.

5.1 Media Storage

Many organizations use write-once, read-many (WORM) media for long-term storage needs due

to its secure and cost effective features. Current WORM technologies include optical discs such

as CDs and DVDs, while older systems may use magnetic disks or tape. A disadvantage of

using WORM media is that record management can be cumbersome. For example, a CD can be

destroyed, damaged, or easily removed from its environment, which is not the case with data

stored on servers. The storage capacity of WORM media is also a concern. It may take

considerable time to copy all video data required for long-term archiving.

In contrast, a secure server with appropriate disk storage offers a central, searchable repository of

video images, which can be easily accessed, recalled, and viewed by authorized personnel.

Servers also enable data to be migrated automatically and suffer no loss within a RAID system.

RAID storage allows images to be distributed across multiple hard disk drives to protect against

a single point of failure. RAID systems conduct integrity checks and perform repairs from the

parity disk if data integrity has been compromised. WORM devices have minimal to no data

recovery capability if they are damaged.

CCTV Technology Handbook

5.2 Scalable Network Storage

Data storage in CCTV systems is changing rapidly and has been influenced greatly by IP-based

systems requiring efficient and cost effective storage. The market offers various network storage

options for IP-based systems and hybrid systems, which incorporate both analog and IP

technology and communications protocols. Most organizations with a sizeable CCTV system

will require network storage beyond local DVR storage capabilities. Network storage involves a

physical separation of storage media from the end user. For example, storage media located

within a recording device (e.g., a hard drive or DVD) has limited capacity, but network storage is

independent from the recording device and offers greater scalability for the large storage

demands of video images.

5.2.1 Interface Protocols

Connecting servers to storage devices is typically accomplished through use of small computer

systems interface (SCSI) protocol. Within CCTV systems, SCSI is the most dominantly used

storage interface. With the increase in available IP technologies and the need for interoperable

and open architecture, the iSCSI protocol incorporates new capabilities to access voice, video

and data from multiple types of network storage devices and make it available across an IP

network. The “i” in iSCSI stands for Internet and in the simplest terms, iSCSI combines the

SCSI storage capabilities with the transmission control protocol/internet protocol (TCP/IP).

Network storage device options include direct attached storage, storage area network, and

network attached storage. These are discussed below.

5.2.2 Direct Attached Storage

DAS is considered an older technology that was developed as a stand-alone mechanism to

connect hosts to storage devices through a direct, one-to-one SCSI attachment. Adding storage

and servers to a DAS system to meet demands can result in a proliferation of server and storage

islands. In a DAS environment, storage sharing is limited because of its direct affiliation to the

servers. DAS is still used today in CCTV systems, but external storage solutions are usually

better options for CCTV video than fixed DAS storage. As LANs gained popularity, the server

attached storage (SAS) was developed as an alternative to DAS in order to achieve a distributed

approach via a LAN.

5.2.3 Storage Area Network

A SAN consists of communications infrastructure

and management layers that ensure secure and robust

data transfer. Storage appliances within the SAN

contain data blocks. Operators access the data blocks

when needed over the network. A SAN is a

dedicated, high-performance network, typically using

fiber channel technology, as seen in Figure 5-1.

Fiber channel protocol and interconnect technology

provide high performance transfers of block data.

SANs are generally used to connect numerous

storage devices such as DVRs and NVRs to one or

more centralized, shared storage systems. An

Figure 5-1. Storage Area Network

CCTV Technology Handbook

increasing number of CCTV components are being designed to connect directly to SANs via

iSCSI.

5.2.4 Network Attached Storage

NAS systems record and access data in file format

and consist of an engine that retrieves files from

one or more storage devices. With NAS

technology, servers maintain file systems on their

local storage, and clients can access files at servers

over a network via LAN or WAN technology,

typically using Ethernet. NAS protocol is

typically TCP/IP based, like the example shown in

Figure 5-2. NAS is considerably less expensive

than DAS and SAN; however, many

considerations for the entire CCTV system will

need to be evaluated to ensure NAS is compatible

with other system components.

Figure 5-2. Network Attached Storage

VIDEO ANALYTICS

Video analytics software is often referred to as automated video surveillance, intelligent video,

smart video, or video motion detection. The capabilities of video analytics are very beneficial

within a CCTV system. Video analytics uses computer algorithms to monitor real-time video

captured by CCTV cameras to enhance security surveillance of people, vehicles, objects, and

their associated behaviors within a camera’s view. Video analytics can help organizations

become more efficient by automating part of the monitoring process and averting the

time-consuming and tedious process of reviewing extensive quantities of stored video.

Video analytics systems can be used to identify suspicious activity in airports, train stations,

seaports, and any other high traffic areas. A common application of video analytics is constant

monitoring of surveillance video to provide an alert to security officers on events, such as an

unauthorized intrusion in progress or a suspicious individual loitering in the parking lot. Some

video analytics systems include license plate recognition (LPR), which provides law enforcement

and security personnel with an automated tool to identify vehicles from the information on their

license plates. Analytics applications also include traffic and tollbooth monitoring, facility and

border surveillance, building and parking lot security, and identifying vehicles of interest.

Additional information on video analytics is included in the Video Analytics Systems Market

Survey Report available in the SAVER section of the DHS S&T website.

SYSTEM INTEGRATION

The complexity and sheer number of components, software applications, inputs, outputs,

transmission infrastructure, processing and storage devices, and customized settings of CCTV

systems provide a wide range of possible configurations to meet an organization’s requirements.

Integrating CCTV components requires thoughtful planning when new elements are brought

online to achieve new capabilities or improve performance.

CCTV Technology Handbook

Organizations benefit from system integration by removing stove-piped systems and their

associated operations and maintenance costs. Integration will also improve data communications

among complementary systems as well as efficiency. The training requirements alone to ensure

operators understand all the features and functions of non-interoperable systems would be

overwhelming. Alternatively, greater uniformity and interoperability among devices and

communications architecture improves an organization’s ability to maintain a CCTV system.

Organizations focused on implementing integrated solutions will likely have fewer instances of

compatibility issues and system failures.

7.1 Systems Approach

Organizations should strive to have all security systems and their subsystems linked together to

ensure the system’s components work together as a whole. Achieving systems integration is

both a conceptual and a logistical challenge. Figure 7-1 illustrates the many different layers

involved in an integrated security system.

Figure 7-1. Integrated Security System

7.2 Integrating CCTV Components

Newly designed CCTV systems have an advantage over existing systems because they can be

designed from start to finish with current technology components from manufacturers that are

easy to integrate. When selecting CCTV devices, organizations should consider future needs and

requirements, such as the potential for expansion, scalability, integration, and upgrading.

CCTV Technology Handbook

Some additional technology considerations include:

• Ability to use a consistent hardware platform throughout the enterprise;

• Off the shelf software and equipment, not proprietary;

• Compatibility for data collection and storage;

• Advanced software graphical user interfaces (GUIs) to integrate controls and displays;

• Ability to create single security user profiles used by multiple security applications;

and

• Vendor support to facilitate, test, and commission system integration.

7.3 Other Considerations

An organization should consider system integration during the project planning and design

phase. This applies to various types of projects that may impact the CCTV system including:

• New CCTV systems;

• Acquisition or expansion of existing structures into an existing CCTV system;

• Newly designed and built structures;

• Upgrades to associated parallel systems;

• Adding new technologies into an existing CCTV system; and

• Expansion of cameras (renaming cameras across stove-piped platforms could be a

problem).

Organizations should ensure that any new projects have a commissioning process to ensure

proper integration of CCTV components and enterprise system integration.

Visual tools, such as camera feeds, maps, facility blueprints, and alarm logs, available in a

monitoring facility are valuable in assessing and determining the best response or course of

action. Monitoring facilities can range from a small room with a single operator to a robust

emergency operations center with many pods of workstations, interdisciplinary operational and

planning experts, computers, printers, phones, and a video wall. Considerations for the overall

monitoring facility are described below.

Room Configuration–Size, lighting, climate control, and several other factors are key elements

in the overall effectiveness of the personnel monitoring a CCTV system, as well as the longevity

and function of the equipment. The size of a well-designed monitoring facility is a function of

the number of monitors, screen sizes, personnel workstations, and other factors. It is common

for a traditional monitoring room to have a bank of 20 or more monitors. New techniques in

digital video analysis are helping to reduce the need for a large numbers of monitors, but some

basic rules still apply to positioning a user at a predetermined distance from the monitors. Large

flat screens placed on walls offer more possibilities in facility design.

Lighting–The location, type, and intensity of lighting in a CCTV monitoring facility are very

important. Light sources should be placed to minimize reflections of direct light from the

monitor screens. Lighting should be indirect and either bounced off white walls or ceilings, or

placed behind the monitors. Fluorescent lights should not be used because of their 60-Hz flicker

CCTV Technology Handbook

and the possibility of EMI with the video system. The brightness of room lighting should be

adjustable to reduce eyestrain, and low enough that personnel can see the detail in the monitor

images. Lower room lighting allows monitors to be set for lower brightness and contrast, which

prolongs the life of certain monitors. Electronic handheld test pattern generators are used to

achieve a good balance between room lighting intensity and the brightness and contrast settings

on the monitors. Another environmental issue is flickering images, which are a problem

especially noticeable in an operator’s peripheral vision. Some manufacturers control flicker by

increasing the scan rates.

Climate–Monitors and other components of CCTV systems generate heat. Space should be

allocated around each piece of equipment for ventilation. The central monitoring facility needs

an adequate air conditioning system to ventilate and cool equipment and provide for the comfort

of personnel. Since monitor screens carry static electrical charges which attract dust, ventilation

systems for the room should be filtered. To protect equipment from the particles and oils in

tobacco smoke, smoking should be prohibited. Proper temperature control and ventilation can

significantly improve the longevity of many CCTV components.

Ergonomics–Good ergonomic design in a monitoring facility is essential for the well-being and

effectiveness of personnel. Building a monitoring center in an existing space designed originally

for other purposes can lead to compromises in ergonomics. Comfortable and adjustable chairs,

workstations with variable heights, live plants, bottled or filtered water, and consoles that are

easy to navigate enhance the alertness of the operator and reduce fatigue. Monitors, keyboards,

and other components should be placed at correct heights and angles to optimize personnel

performance and reduce repetitive stress injuries.

Staffing–A significant consideration when planning for the staffing of a CCTV system is the

number of monitors an operator can view and comprehend simultaneously for a specified period

of time. More than one operator may be necessary for effective coverage in facilities with a

large number of monitors.

EMERGING TECHNOLOGY

The CCTV industry is part of an ever-changing IT environment. New capabilities in any one of

the digital components, Internet, or telecommunications industries will eventually be applicable

to CCTV systems. Entities investing in new CCTV systems or upgrades are incorporating these

new technologies as they become available. While it is unclear how new IT developments will

be addressed by the security surveillance industry in the future, the popularity of IP-based CCTV

systems in recent years illustrates how the market may respond to similar innovations. This

section explores how CCTV systems may be influenced by new developments and evolving

expectations from users to improve existing equipment and software. It also discusses several

emerging IT trends that could factor into future CCTV products and platform integration

capabilities.

8.1 Digital Technologies

Newer CCTV systems are being built entirely with digital components, from the cameras to the

recording devices, and no longer require conversion back and forth between analog and digital

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video signals. Computers and digital recording devices are replacing tape-based storage systems,

multiplexers, and switching systems.

Since any kind of information can be digitized, CCTV systems can integrate with almost any

other information handling system. They can be programmed to process, analyze, display, and

store data from other media and from other surveillance sensors. CCTV can be blended into a

facility’s intrusion detection, access control, and alarm systems so that information from all

devices is displayed to security personnel on the same displays, images, and maps. As a result,

security monitoring personnel have access to multimedia presentations that merge video with

radar, laser radar, sonar, intrusion detection alarms, satellite mapping, and imaging to create

integrated visual situation images.

8.2 Improvements to Existing Technology

Many existing CCTV systems can be updated with current technology that incorporates new

features to meet evolving consumer needs and expectations. Cameras will be made smaller and

lighter and will consume less power. CCTV components are being designed to handle increased

data and file sizes. Video compression algorithms are becoming more efficient, and network

traffic management solutions are improving capabilities to store, retain, archive, and recall video

as needed. Vendors may also focus on their product’s capabilities to effectively integrate CCTV

system hardware and software.

8.3 Major IT Trends

The major trends in CCTV systems are primarily related to developments in the information

industry and the need for products and components to adopt new technology environments and

capabilities. As new innovations related to digital formats and business-based IT solutions are

realized, the CCTV industry will see a significant number of new capabilities. While some new

technologies will involve hardware, the majority of emerging technologies will likely be focused

on the interpretation of video through software, data storage management, and system

integration.

9. VENDOR SELECTION CONSIDERATIONS

Selecting CCTV system vendors can be a challenge. Professional industry support is available

from a host of companies, some of which offer a full suite of services and products. Others may

offer more specialized services as designers, manufacturers, suppliers or authorized equipment

dealers, installers, or integrators. The CCTV market evolves continuously with many vendors

both entering and exiting the marketplace. Organizations may have internal expertise that can

fill certain roles, but any new, expanded, or upgraded CCTV system will require engagement

with some form of professional industry support.

9.1 Selection Criteria

Experienced vendors may provide invaluable expertise to organizations seeking upgrades of

older technology CCTV systems. However, some new vendors may have more specialized

expertise in a particular emerging technology. Determining the most important criteria prior to

selection is a fundamental step in finding the best suited vendor. Criteria can include the

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vendor’s previous experience and past performance with CCTV products/services, their level of

sophistication with integration of CCTV components, technical support offered, and total cost.

9.2 Vendor Resources

Selecting a well-qualified and experienced vendor with the capabilities to meet desired

qualifications will help increase the quality and performance of the overall CCTV system. The

following organizations’ websites provide information on CCTV system vendors, their related

areas of expertise, and contact information:

• ASIS International;

• Security Industry Association;

• Security Magazine; and

• SANS Institute.

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APPENDIX A. GLOSSARY

The following represent terminology commonly used and/or associated with CCTV systems.

Not all terms have been used in this handbook.

Angle of View–The angular measure of a lens’ field of view (FOV) on the diagonal of the

image, expressed in degrees or radians. Vertical and horizontal angles of view are also

sometimes stated.

Aperture–The opening, located within the optical path between the front of the lens and the

focal plane, that allows light to pass. The size of the aperture determines the depth of field and

the time required to adequately expose an image. The size of the aperture is controlled using a

multi-leaved adjustable device called a diaphragm or iris.

Aspect Ratio–A numerical expression for the ratio of the image height to the image width

represented as a ratio, such as 4:3, or a number, such as 1.33.

Aspherical Lens–A lens with a surface geometry that is not derived from a portion of a spherical

surface. Aspherical surfaces are much more complex to calculate and manufacture than

spherical surfaces. Using aspheres allows lens designers many more options to design lenses

than spherical designs alone.

Automated Video Surveillance (AVS)–See Video Analytics.

Backlight Compensation (BLC)–A video contrast control that corrects the exposure of persons

or objects in front of a bright light source.

Bandwidth–A measure of the capacity of a communications channel. The higher a channel's

bandwidth, the more information it can carry.

Blooming–The defocusing effect that occurs around bright areas in an image, where the intensity

of the incoming light has exceeded the imager’s ability to produce a usable image.

Camera Fusion–An emerging technology that allows a single video image to be created from

separate video signals. Camera Fusion can integrate video signals from image sensor, intensifier,

and thermal imager technologies into a single output, selecting each pixel to provide the best

contrast in the final image.

Cathode Ray Tube (CRT)–The term used to denote a video terminal or television set that

operates using a “picture tube.”

CCTV Camera–A video camera employed in a CCTV system.

Character Generator–An electronic device that can insert text into an image. Character

generators can be used to watermark an image or apply a date/time stamp to a recording.

Charge-Coupled Device (CCD)–A type of image sensor, an array of photocell semiconductors,

used to create a digital image. CCDs are used in cameras, document and image scanners, and

other devices.

Compressor/Decompressor (CODEC)–A CODEC is a set of algorithms for compressing and

decompressing large files, such as a video file.

Color Resolution Chart–A test chart used to determine the resolution of a camera or lens in

terms of color response.

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Complementary Metal Oxide Semiconductor (CMOS)–A type of image sensor used in a

camera to detect light and create a video image. CMOS sensors require less electrical current

than CCD image sensors, and are often found in applications requiring portability or small size.

Common Intermediate Format (CIF)–A standard that defines the sizes (width and height in

pixels) of full and reduced-size images. A full CIF image is 352 x 288 pixels per image. QCIF

(176 x 144) contains one quarter of the information of a full CIF. QQCIF (88 x 72) is a quarter

of a quarter CIF and are often referred to as thumbnails, and contain 1/16 the information of a

full CIF image.

Compression–Algorithms used to compress digital image files to conserve bandwidth and video

storage capacity. Moving Picture Experts Group (MPEG) and Motion Joint Photographic

Experts Group (MJPEG) are examples of video compression formats.

Consumer Camcorder–A small, handheld, electronic video camera, combined with a video

recorder, intended for home use.

Convex Parabolic Mirror–A bowl-shaped mirror, which creates a panoramic image that can be

recorded by a camera focused on the mirror.

C-Mount (cine-mount)–One of two predominant video camera lens mounting methods.

C-mount lenses have a 1-inch mount diameter with a thread pitch of 32 threads per inch and

focus 17.5 millimeters behind the rear lens element. A C-mount lens can be used on a CS-mount

camera (see CS-Mount) by placing a 5 millimeter spacer ring between the lens and the camera.

CS-Mount (cine-short-mount)–One of two predominant video camera lens mounting methods.

CS-mount lenses have a 1-inch mount diameter with a thread pitch of 32 threads per inch and

focus 12.5 mm behind the rear lens element.

Date/Time Stamp–The capability to insert the current date and time into an image during

recording.

Day/Night Camera–A camera that provides color images in daylight conditions and black and

white images in low-light conditions. When the ambient light falls below a certain level, an

internal mechanism automatically removes the infrared (IR)-cut filter from the optical path and

the camera switches to black and white mode.

Depth of Field–The front-to-back distance along a camera’s axis of view where the image

appears to be in focus. Depth of field is a function of the size of the imaging device, lens focal

length, and lens aperture setting.

Digital Camera–A device that records a digital image or stream of images in a digital format.

Digital Imager–A fundamental component of every digital camera. The imager records the

view received from the camera lens, also called a sensor.

Digital Signal Processing (DSP)–The set of algorithms or rules used to generate visual images

from digital information. DSP can be implemented as software, firmware, or hardware.

Digital Video Recorder (DVR)–An electronic device that records video images and stores them

to a computer storage device, such as a hard drive.

Direct Attached Storage (DAS)–A video storage technology used to connect hosts to storage

devices via a direct, one-to-one small computer system interface (SCSI) attachment.

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Electron–Electrons are negatively charged subatomic particles, the movement of which is the

basis for electricity.

Electron Guns–CRT devices, such as televisions and computer monitors, function using

electron guns. These guns fire electrons at the interior surface of the face of the CRT, which is

coated with phosphor compounds. The phosphors glow when electrically charged, creating a

visual display.

Electronic Noise–Static in a video system, seen as graininess or snowiness in the image on the

screen.

F-Stop–The ratio of the focal length of the lens to the diameter of the aperture. The smallest

number represents the widest aperture. The aperture size and the shutter speed determine the

amount of light reaching an image sensor.

Fiber Channel (FC)–A high-speed network protocol and interconnect technology that provides

high performance transfers of block data between networked storage devices.

Field of View (FOV)–The size of the area that can be seen while looking through an optical

device. This area can be calculated using a lens calculator.

Fisheye Camera–A camera that employs an ultra-wide-angle lens that has an angle of view that

may exceed 180 degrees and has considerable barrel distortion.

Focal Length–The distance between the optical center of the lens and the plane behind the lens

where the image is formed. For a particular size of imaging device, the focal length determines

the angle from which the lens accepts light or the angle of view.

Focus–The process of adjusting the distance between the lens and the focal plane so that objects

of interest appear crisp and sharp in the final image.

High Definition Television (HDTV)–An improved television system that provides

approximately twice the vertical and horizontal resolution of previous television standards.

Horizontal Resolution–The number of alternating pairs of vertical black and white lines that

can be recorded by a camera and/or reproduced by a television or monitor.

Hybrid DVR–A video recording device that incorporate functions of both network video

recorders (NVRs) and DVRs by accepting and converting video images from analog cameras as

well as IP video inputs.

Image–A two-dimensional representation of a FOV.

Intelligent Backlight Compensation–A set of rules for changing the intensity of the pixels in an

image to improve the perception of details and contrast. These rules are employed when the

ambient light interferes with the details in the captured image.

Intelligent Video–See Video Analytics.

Intensifier–An electronic device that amplifies the effects of limited numbers of photons (low

levels of visible light) in a near-dark FOV. Intensifiers are used to provide images under low

levels of illumination from the stars, moon, or other light sources.

Interlaced Picture–Scanning two sub-pictures (horizontal lines) to make up one picture frame.

Many television systems only transmit one half of an image with each pulse of analog signal.

The horizontal lines of the image are divided into even and odd sets, and the video signals

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alternate sending the sets of horizontal lines to the television or CCTV monitor. Systems using

interlaced video signals require two pulses of video signal to make one complete image.

Infrared (IR)–The region of the electromagnetic spectrum that lies slightly past barely visible

red light. The IR band starts at wavelengths greater than 750 nanometers, and extends to about

1,200 nanometers. There is no universal agreement on the boundaries of the IR band.

Infrared-Cut Filter–A filter used with an IR sensitive camera to improve performance during

daylight operation. Such filters are often found on day/night cameras.

Infrared Illuminator–A light source that produces IR (invisible or barely visible) wavelengths

of light. IR illuminators are used as spotlights or floodlights for cameras sensitive to reflected IR

light.

Iris–The iris is the physical mechanism that can be opened or closed to change the size of the

aperture.

Internet Small Computer System Interface (iSCSI)–An Internet protocol (IP)-based

networking standard used for linking voice, video, and data from multiple types of network

storage devices.

Joint Photographic Experts Group (JPEG)–A standard for photographic image compression.

JPEG is a lossy compression method, which discards data from an image and interpolates the

surrounding area.

Kilobyte (KB)–Each KB is composed of 1,024 bytes, and each byte is composed of an 8-digit

binary number.

Lens–An optical device that bends or refracts rays of light to produce an image.

Light–The portion of the electromagnetic spectrum that is visible to the human eye.

Light Sensor–A device used to detect either the presence or absence of light or to measure the

intensity of light present in an environment.

Lipstick Camera–A small, self-contained electronic camera often used for covert surveillance.

Local Area Network (LAN)–A network configuration used to connect computers and

peripheral devices in close proximity to one another in order to share resources, such as files,

applications, and printers.

Lux–The basic unit of illumination, equal to 1 lumen per square meter, or 1/10 of 1 foot-candle.

Megabyte (MB)–1 MB is composed of 1,024 KB. See Kilobyte.

Monitor Station–A workstation designed for the presentation of visual information.

Microbolometer–A type of sensor for the detection of long-wavelength IR energy, which

radiates from all objects as a function of their respective temperatures. Microbolometers are one

type of sensor used in thermal cameras and heat sensing devices.

Monochrome CCD Sensor–A CCD sensor that does not record color information.

Monochrome CCDs are used in monochrome CCTV cameras, particularly ones used in low-light

applications to detect reflected IR energy.

Motion Detection–See Video Analytics.

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Moving Picture Expert Group (MPEG), Motion Joint Photographic Experts Group

(MJPEG)–Digital formats for streams of images that record motion.

Network Attached Storage (NAS)–A network storage technology used to record and access

data in file format from one or more data storage devices.

Network Video Recorder (NVR)–A software application that records video transmitted over an

IP network from multiple CCTV digital cameras to a variety of storage devices.

Neutral Density Filters–An optical filter that reduces the total amount of light entering the

camera evenly across all visible light wavelengths. The filter is often used to force open a lens

aperture to minimize the depth of field so that the focus setting of a camera lens can be made in

bright locations.

Oscilloscope–A type of test equipment used to observe electronic signals.

PAL (Phase Alternating Line)–A video signal standard used outside the U.S. The PAL

standard requires 50 Hertz (Hz) electrical power distribution.

Pan-and-Tilt Devices–A movable camera platform that allows the camera to be aimed or

pointed at objects of interest.

Panoramic View–An unbroken view of a wide arc (often 180 degrees or more) of a horizon.

Peltier Cooler–A type of electrically powered heat sink used to cool electronic devices that have

performance degradation when operating at higher temperatures.

Personally Identifiable Information (PII)–Unique personal information that can be used in

conjunction with other resources to identify, locate, or contact a specific individual.

Phosphor Elements–The chemical compounds which line the inner face of a CRT video

display. The phosphor elements glow when struck by the streams of electrons, producing the

picture seen on the CRT.

Photon–In quantum physics theory, a photon is a single discrete unit of light or a packet of light.

Pin-Hole Lens–A small, fixed focal length lens often used in covert camera applications.

Pixel–A picture element, the smallest component of a visual display. The resolution of a video

monitor is proportional to the number of pixels used to generate the display.

Polarizer–A special neutral-gray colored optical filter that can be rotated to selectively pass light

oriented along a very narrow axis relative to the filter. The light originating from outside the

axis is blocked. A polarizer is often used to reduce or eliminate reflections from window glass

and water surfaces.

Pyroelectric Sensor–A type of sensor device for the detection of thermal infrared radiation.

Resolution–The term resolution is used to express the level of detail that can be captured by a

sensor, camera imager, or camera, or displayed by a video monitor. Resolution applies to the

horizontal, vertical, and color characteristics of the details in an image.

Resolution Chart–A printed graphic used as a target image, a resolution chart provides a

demonstrated system performance value, which can be compared with stated parameters to

determine if a system is functioning normally.

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SECAM (Sequential Color and Memory)–A video transmission format used in France and

other nations.

Sensitivity–Relates to the minimum quantity of light required for the camera to produce an

image, as well as to the resolution of the camera imager. Images taken at high resolutions

require more light to produce.

Server Attached Storage (SAS)–A data sharing storage technology that was developed as an

alternative to DAS in order to achieve a distributed approach through the use of a LAN.

Signal to Noise Ratio (SNR)–Expresses a performance characteristic of a camera’s ability to

produce a clean and clear image. SNR values are usually given in decibels (dB), with higher

values more desirable than lower.

Small Computer System Interface (SCSI) Protocol–A set of command, protocol, and interface

standards used for connecting and transferring data between computers and peripheral devices.

Smart Video–See Video Analytics.

Software Algorithms–A problem-solving procedure composed of a series of steps or

instructions. Any useful computer program contains a set of algorithms.

Storage Area Network (SAN)–A data sharing storage technology that consists of

communications infrastructure and management layers.

Thermal Camera–A camera that creates an image from the thermal IR radiation emitted by

objects. The IR energy radiated from objects depends on the objects’ temperatures and is

displayed as different colors or shades of gray.

Third Generation Intensifier–The newer generation of image intensified night vision

technology often found in tactical equipment such as night vision goggles.

Transmission Control Protocol/Internet Protocol (TCP/IP)–An Internet communication

protocol that defines rules for data format, addressing, routing, and transfer so that computers

can communicate with one another.

Vector Output–A method for combining multiple inputs into a single output.

Vectorscope–An oscilloscope used to set up and measure the chrominance portion of a video

signal.

Video Analytics–A technology that uses software to analyze the video image stream. Video

analytics software may provide object detection, recognition, identification, tracking, and

analysis in a variety of surveillance applications.

Video Motion Detection (VMD)–When the current image changes beyond a threshold value,

the system triggers one or more pre-programmed actions and initiates an alarm.

Video Monitor–An electronic device for displaying video output that may be digital or analog.

Watermarking–The process of adding a semi-transparent layer of verbal or visual information

onto an image. Watermarking is often used as part of an authentication process.

White Light–White light is made up of all colors of the visible portion of the electromagnetic

spectrum, from about 500 nanometers to about 700 nanometers.

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Zoom Lens–Zoom lenses are variable focal length lenses that are designed to maintain a focus

setting throughout the zoom range. Many zoom lenses have an integral motor that allows remote

operation of the focal length setting.