Video Surveillance Systems PDF

Chapter 8: Video Surveillance Systems Surveillance Concepts Video Surveillance is often referred to as Closed-Circuit Television (CCTV); however, video surveillance systems are no longer a closed circuit and they do not use televisions for viewing images. For purposes of this book, we will use the...

Chapter 8: Video Surveillance Systems Surveillance Concepts Video Surveillance is often referred to as Closed-Circuit Television (CCTV); however, video surveillance systems are no longer a closed circuit and they do not use televisions for viewing images. For purposes of this book, we will use the term "video surveillance" rather than CCTV; however, it is important to note that these two terms are still used interchangeably within the security industry. The application drives the implementation of video surveillance systems, not the other way around, and all systems should be designed in such a way as to meet the overall physical protection system requirements for risk management and asset protection. The video surveillance system should use a systems approach not components approach during the selection process. Video systems should be designed with future growth in mind and for potential changes in the system requirements. Although all video surveillance systems will become obsolete at some point in time, it does not mean that they will be ineffective for the original application. If a system has become obsolete, but still is functioning effectively, it means that the original application was properly designed. There are three main reasons to use video surveillance systems in security applications; 1) to witness an event or activity, 2) record what has happened for evidence, and 3) assess incidents and activity. Video surveillance systems may also provide a deterrence value in the prevention of crime. Analog video systems are inexpensive and difficult to hack when compared to digital video systems. However, digital systems can be networked and offer increased flexibility over analog systems. In addition, digital cameras may have the ability to save images in the camera should the recording medium fail. The first analog cameras used tubes that were susceptible to burn-in from images. Solid-state cameras replaced the tube type cameras, which provided longer-life and prevented burn-in. Now, analog systems are being converted to digital signals by use of a digital encoder (codec) so they can be connected to the network. Converting an analog signal to digital required four major technology changes: ·Convert analog to digital signals ·Use a TCP/IP network instead of coax to transmit imagery ·Compress image files to fit within a network\'s bandwidth capacity ·Compress image files to fit within limited available storage capacity Functional requirements can also be determined by answering three simple questions: 1.1. What is the purpose of the system? 1.2. What will each camera view? 1.3. What are the requirements for recording-real-time viewing or recorded video? Detection without assessment is not considered detection and, often, video surveillance systems supplement security officers and serve as a cost-effective solution in providing detection, assessment, and surveillance capabilities. Security officers are better at the assessment function than at the detection function. The surveillance system can be integrated with video detection capabilities, such as video motion detection, while incorporating additional dedicated cameras for surveillance, assessment and recording purposes. In high-security applications, the video cameras may be interfaced with intrusion detection devices and access control to provide immediate assessment capabilities when an alarm is triggered. Video surveillance cameras must consider three factors to determine the field of view requirements: ·Target-people, vehicles, objects, packages, weather, traffic, etc. ·Activity -trespassing, robbery, vandalism, assault, or package/object left behind ·Purpose-assessment viewing, video patrols, facial identification, etc. Performing the assessment function using a video surveillance system can help to determine: 1) What is happening, 2) What has already happened, or 3) Whether undesirable activities can be deterred or discouraged. Video surveillance systems often use three levels of assessment, which are: ·Subject Identification. The ability of the system to identify details is critical when using the video footage for criminal investigations. The system should be able to determine the subject beyond a shadow of a doubt. If this cannot be accomplished, then the camera should be relocated to provide the correct angle of view. A steep camera angle makes it more difficult for identification using video imagery. The subject should occupy at least 10 percent of the overall scene width. The average person is 2 feet (0.6 m) wide, which means when recording the scene can be no wider than 20 feet (6 m) wide for subject identification. For example, a person viewing a \$100 bill from 3 feet (0.9m) could identify that it is a \$100 bill. However, if you were to move that \$100bill 30 feet (9 m) away from a person, they would not be able to identify the specific currency amount. ·Action Identification or Classification. The ability to detect the type of person or object and the corresponding activity. For example, a person enters a room and places a piece of mail on a desk; a second person enters the room and now the piece of mai1 is missing, but the first person did not see the second person take the piece of mail. This is where an automated trigger (such as video motion detection or video integration with an intrusion sensor) might be useful in detecting and recording such activity. ·Scene Identification or Detection. Each scene must be able to stand on its own merit. The screen should show the area where the act has occurred. The scene itself should accurately identify what is happening without additional information. The main elements of a video surveillance system are as follows: ·Scene-location or activity to be observed. ·Field of View-the area viewed through the lens of the camera ·Camera - coverts the digital or analog signal to an electronic signal for transmission. The camera includes mounting and the camera housing. The camera should always be chosen before the lens. ·Lens-determine the size of the field of view and the clarity of the image. ·Communication Transmission-how the signal from the camera is transmitted to the equipment for viewing or recording. ·Monitor-displays the images for viewing from a camera or multiple cameras. ·Recording-includes any computer, hard drives, or recording equipment that is used to capture and store imagery from the system\'s cameras. ·Controllers and automation equipment-controls what the cameras view (including Pan/Tilt/Zoom camera functions) and how the video is stored. Since video systems only have three main components-camera, monitor, and cable-the system should be kept in perspective. As stated previously, let the application choose the equipment and not the other way around. It is important to design the system generically keeping an open-minded equipment design. An open-minded equipment design does not always specify the best equipment or latest models of system components. Design the system using the best and most comprehensive option first. Once the final budget is established, you can always remove some elements to keep the cost in line with the budget. The system doesn\'t need to be built all at once. Budgets and projects can be stretched over years, if necessary, but it is important to choose equipment that will most likely be available in the upcoming years and equipment that has a long lifecycle. The implementation of a video surveillance system should be properly defined before requesting pricing. The seven-step process includes: ·Define the system\'s purpose. By defining the system\'s purpose, the type of components will be easier to establish. ·Define each camera\'s purpose. This will help in determining how many cameras are necessary. ·Consider the area to be viewed by each camera. If more area needs coverage, then consider installing additional cameras. ·Choose the type of camera. Make sure it has the appropriate lens and illumination. ·Choose the proper lens for each camera. The lens must match the camera formats. ·Determine the best transmission method to get imagery from the camera to the monitor. ·Determine the control area, triggers, interfaces, and priorities for each camera. It is also critical to choose the proper storage technology and automation requirements. Analog Surveillance There are three main components in an analog video surveillance system: 1) Camera,2) transmission cable, and 3) monitor. Other analog video system components are: ·Lens-must be chosen based on environment conditions and field of view requirements. ·Pan/Tilt/Zoom (PTZ)-offers motorized movement of the camera view and zoom capabilities. ·Controller-to control PTZ cameras or automatic lens. ·Video recorder-tape or digital recording medium used to save images. ·Video switcher-allows for multiple camera displays on one monitor. ·Video transmitter/receiver - allows video signal to be transmitted and received. Coaxial cabling is the most common medium. Listed below are the types of cabling and distances: \- RGU-59 coaxial less than 750ft.(229m) \- RG-6 coaxial-750 ft. (229 m) to 1500 ft.(457m) -RG-11 coaxial-1500 ft. (457 m) to 2500 ft.(762m) \- Fiber optic cabling for anything over 2500 ft.(762m) ·Analog Video Amplifier-allows video signals to be sent over long distances. All analog surveillance cameras employ a 2-to-1 interlace pattern. The monitor first paints the horizontal pattern (odd number sweep lines) and then paints the vertical pattern (even number sweep lines). Although no longer in use today, due to digital video resolution, these analog standards were defined by the NTSC or PAL standards. Below is some basic information on NSTC and PAL: National Television Standards Committee (NTSC)-US/Japan ·60 fields per second (half pictures) ·525 vertical lines ·Employ 2:1 interlace pattern ·Paints odd \# horizontal line of the image ·Re-sweeps with even \# of horizontal lines of the image ·30 complete frames per second ·Replaced by digital video Phase Alternation Line (PAL)-Europe/China ·50 fields per second (half pictures) ·625 vertical lines ·Employ 2:1 interlace pattern ·Paints odd \# horizontal line of the image ·Re-sweeps with even \# of horizontal lines of the image ·25 complete frames per second ·Replaced by digital video Digital Surveillance There are three main components of a digital video surveillance system: 1) Camera,2) digital transmission (CAT 5E or 6E cable) or digital network, and 3) personal computer with viewing software (can also be tablet computer or smartphone). Other digital video system components are: ·Digital electronic scanning software- this allows a fixed megapixel camera to appear as if it is a PTZ device because it allows scanning of the image in a predetermined path (rather than moving the camera). ·Video switcher-usually built into the digital video recorder as a multiplexer. ·Lens-IP camera lens can automate various functions of the lens (auto-iris, zoom, and focus). ·Controller- usually operates with a computer keyboard or mouse by a Graphical User Interface (GUI) ·Digital Video Recorder - digital recording medium used to save digital imagery. ·Video transmitter/receiver-Ethernet, fiber optic, or wireless. ·Video Amplifier-allows video signals to be sent over long distances. The maximum cable length for standard digital cabling (CAT 5E & 6E) is 328 feet (100m). A digital video surveillance system does not use a 2:1 interlace pattern, but rather uses a full grid of small, colored squares known as pixels and measures in frames per second (fps) or images per second (ips) using the Common Intermediate Format (CIF) resolution; see below for some examples: QCIF,176X120 21,120 pixels,CIF,352 X 240 84,480 pixels,4CIF,704 X 480 337,920 pixels,16CIF,1280 X 1024 1.31 megapixels,25 CIF,1700X1200 2.04 megapixels,36 CIF, 2112 X 1440 3.04 megapixels, A 4-megapixel image is equal to a 400 ASA film resolution and a 6-megapixel image equals a 100 ASA film resolution. The resolution of a camera is determined by 1) camera, 2) transmission method, 3) the weakest link on the video system interface, and 4) the reproductive capability of the image storage system. Video Surveillance Cameras When choosing a camera, one should base it upon 1) sensitivity, 2) resolution, and 3) camera features: Sensitivity. Sensitivity is the minimum amount of light needed to produce a quality image. Lighting (sensitivity) is the first consideration when choosing a camera. Cameras come in three sensitivity formats: 1) full light,2) lower-light, and 3) low light. Low light sensitivity requires little to no light Using a lower f-stop lens will allow the most light to enter the camera Use infrared (IR) lighting or thermal technology if visible lighting cannot be used. Resolution. The resolution of the camera (image quality) is the number of pixels or horizontal scans related to picture quality. A few identification views are listed below: General. Clothing and colors indistinguishable, no detail for person-sized target. Five pixels per foot (16 pixels/m). Monitor. Human or traffic flows, no serious level of detail upon blowup. Seven pixels per foot (23 pixels/m). Detect. Humans can be detected but not identified. Eleven pixels per foot (35 pixels/m). Observe. Clothing and colors now distinguishable. Eighteen pixels per foot (58 pixels/m). Recognize. Accurate identification and separation of known individuals. Thirty-five pixels per foot (118 pixels/m). Subject Identification. Identified the person without a shadow of doubt with excellent image blow-up. Forty-six pixels per foot (150pixels/m). In an analog system the subject should equal 10 percent of the overall scene width at the point of recording, with a minimum of 325 horizontal line resolution. License Plate Identification. Excellent detail on image blowup for small object and license plate identification. Seventy pixels per foot (231 pixels/m). Facial Recognition. Extreme detail and element resolution for image blowup. Eighty-eight pixels per foot (289 pixels/m). Camera features. These are the attributes or features needed for the application. Automatic Gain Control (ACG). This circuit is built into the camera to provide additional sensitivity and keep a level video signal as light decreases or in areas with shadows. All exterior cameras should have the ACG feature turned on. ACG degrades the picture quality by a factor of 10 in low-light conditions. Electronic Shuttering. This allows the camera to compensate for light changes without the use of a specialized or manual lens. Note: it is advisable to field test equipment to verify claims by the manufacturer or salesperson. Backlight compensation. This feature provides the ability to view an object despite an extremely bright background. Here are a few ways to meeting various lighting conditions: Auto Iris Lens is an automated lens that adjusts to the average amplitude of the video signal and can adjust to changes in light conditions. Manual Iris Lens allows the video signal to remain constant regardless of varying light conditions and is typically used indoors due to the need for consistent lighting conditions. Masking allows users to divide the video scene (using overlay grids) and then program certain areas of the scene to be ignored. The grids are not visible after the programming process. Electronic Iris de-amplifies bright lighting conditions and amplifies darker scene areas to provide a good image by using true video signal averaging. (For example, someone standing in front of glass doors with a bright background will still be fully visible without any scene washout.) Privacy Blocking/Image Protection provides cameras with the ability to black out a portion of the image scene. This technology is useful in areas which have residential areas adjacent to commercial businesses, or in areas with public settings to prevent the improper use of surveillance cameras to invade personal privacy. Autofocus is the camera\'s ability to focus on a scene automatically. When tracking actions or objects, such as moving vehicles or people, it can automatically focus on the target. Enhanced (Super) Dynamics is a type of analog electronic backlight compensation that uses an onboard processor to double-scan the image scenes to provide a good image despite the differing backgrounds. This is often referred to as multi-scanning. Camera Types Listed below are six types of cameras: ·Analog. These cameras record in monochrome (black and white) or color. Resolutions range from 220 to 580 horizontal lines. Light sensitivity is between.00046 foot-candles (0.005 Lux) to 0.929 foot-candles (10 Lux). Some cameras use an intensifier between the lens and the Charged-Coupled Device (CCD) to amplify the available light by thousands of times. ·Internet Protocol (IP). These digital cameras (both color and black and white) measure resolution in CIF (pixels). For example, 4CIF means that there are twice as many vertical and horizontal pixels to a single image. Some of these cameras are referred to as "edge\" devices because they perform the computing and analytics within the camera (edge device) rather than send the information to the controller to be computed. ·Megapixel Cameras. These cameras can deliver images with more than 1million pixels usually at a minimum resolution of 1280 x 1024 pixels. ·Thermal Cameras. Thermal cameras use temperature signatures of the target to produce images. Cold imagery is shown in shades of blue, whereas hot objects are shown in shades of red. Thermal cameras can be used in applications such as in an ocean harbor to detect ships as far as 5 miles (8 km) away. ·Infrared Cameras. These cameras use infrared light, which is not visible to the human eye, to illuminate the target area. ·Day-Night Cameras. These typically use a removable IR cut filter (during daytime hours the camera records images in color, but at night it removes the IR cut filter to allow IR light into the camera). The images produced at night are black and white. Camera Lens The camera lens is another critical component in a video surveillance system and is the second most important decision, after choosing your camera. There are three major factors in determining the proper lens for a camera. They are: 1) Format size, 2) Distance to Scene, and 3) Focal Length: Format Size. For the best performance, the camera lens format size must match the camera imager. For example, a 1/2-inch camera format should use a 1/2-inch lens format. A smaller lens format will not fit the camera imager and the result will look like \"tunnel vision.\" The format size of the lens must equal or exceed the format of the camera imager. ·The standard lens for a 1-inch camera is a 25 mm lens (image equivalent to the human eye). ·A 1/2-inch lens format would have a standard lens of 12.5 mm. ·A 1/3-inch lens format would have a standard lens of 8mm. Distance from Camera to Scene. The distance from the camera to the scene determines which lens focal length is required. The measurement is taken from the camera lens to the subject area to be viewed. A rotating lens calculator can be used to determine this. Most manufacturers\' websites offer free calculation tools. It is critical that this distance be measured accurately because it may affect the overall performance of the video surveillance system. A manual way to determine the field of view is by using the following example: Camera mounted on building 40 feet high Scene desired is 30 feet from building Use the Pythagorean Theorem: A2+B2=square of the distance between camera to scene 40 ft. x 40 ft.=1600 ft. and 30 ft. x 30 ft.=900 ft. Add 1600 ft.+900 ft.=2500 ft. 2500ft.=502 Camera to Scene Distance is 50 feet. Field of View (Focal Length). The focal length is the most important factor when choosing a lens. The focal length determines the horizontal and vertical angles of the lens (height and width), which is based upon the scene distance from the actual camera lens. The lens focal length is often measured in millimeters (mm). The longer the focal length, the smaller the scene captured. The "f-stop\" number refers to the aperture of the lens. The larger the f-stop number, the less light is being captured by the lens. For low-light conditions a lower f-stop number is desired. Lens options include 1/4-inch, 1/3-inch, 1/2-inch, 2/3-inch, and 1-inch formats. The lens can either have an auto iris that automatically adjusts for light or a manual iris that remains consistent regardless of light conditions. There are several types of lenses: ·Fixed lenses offer fixed focal length (8mm,12.5mm, etc.) ·Varifocal lenses have adjustable focal length within a defined range (8mm to 12.5 mm, etc.). These lenses do not have tracking ability and must be manually refocused each time their range is changed. ·Zooms lenses provide the same views as standard, wide angle, and telephoto all incorporated into one lens. It can be digital or motorized and is typically operated by a person using a controller to adjust the view. These also can be automated to track and adjust the focus of the lens without a human operator. ·Standard lenses are used for average scenes at medium ranges, 15 to 50 ft. (4.5 to 15.25m) ·Wide-angle lenses are used for very wide scenes and short ranges, 0 to 15 ft. (4.5m). ·Telephoto lenses are used for very narrow fields of view, over long distances (over 50 ft./15.25 m). Recording and Image Compression A video surveillance system can provide different types of images and resolutions depending on the type of system. If a video surveillance system is being used to record images, the final resolution of the image may depend on the type of compression (codec) the system uses. If Joint Photographic Expert Group (JPEG)compression is used, the image will be of high quality since the compression ratio is approximately 10:1. The downside with using JPEG compression is that it takes a lot of storage space to record these images and a large amount of bandwidth to transmit the images over a network. The industry has adopted two main forms of compression: ·Moving Picture Expert Group (MPEG-4). Reduces the required storage space by strong compression technology. ·H.264 (also known as MPEG-4 Part 10). This is the most effective and fastest growing compression technology for transmission and storage. Users must have additional processing power to compress and decompress the images. For purposes of using video surveillance imagery in a courtroom for the admission of evidence, there are three aspects you should consider: ·Quality of recordings ·How it was obtained ·Proof of originality (time/date stamp, digital watermarks, etc.) The percentage of the scene occupied by the subject, or even an eyewitness, may also be required if using video in a court of law for evidentiary purposes. The chain of custody of the imagery-how and who handled the video, including storage and transportation-should be documented properly and logged when using video images during a criminal court proceeding. Privacy is a major legal concern for video surveillance systems. Avoid placing surveillance cameras in locker rooms, bathrooms, or other places that employees and visitor have a reasonable expectation of privacy. Audio may or may not be legally recorded, depending on the jurisdiction or country, so be sure to consult with an attorney before deciding to record audio. Signage may be placed to alert people that an area is under surveillance. These are often placed at entrances to the building to reduce the number of signs required. Dummy (fake) cameras should not be used in security applications. Employees and visitors have an expectation of protection while on premise. Installing a fake or dummy camera may provide people with a false sense of protection-such as thinking that onsite security is witnessing an attack and will come to the rescue. Types of Video Recorders There are several different types of video recorders that meet a variety of security needs. ·Digital Video Recorders (DVR) (Analog). These capture analog or digital signals on a hard drive, CD, DVD, or other storage medium. Always test image playback because these recorders must compress images for storage, thereby reducing playback quality-combining colors, lowering resolution, etc. ·Network Video Recorders (NVR) (Digital). These can use analog or digital signals but are better than DVRs and are controllable over a network. They can be used in a system with several hundred cameras. ·Server/Cloud Based (Digital). These systems use a sophisticated software application for control, analytics, and the interfacing of systems. They are typically used for large, complex, systems using a high level of compression and complex storage levels on remote servers. Access can be provided on multiple technology platforms; most often access to the system is via a computer, computer tablet, or smartphone device. ·Managed Video. These are third-party viewing and storage services. Video can be stored remotely and retrieved as needed. Often, the third-party services company can perform the retrieval services, or they can provide access to their services via computer or a personal device (smartphone or computer tablet). ·Interactive Services. These are services such as escorting employees to their vehicles, unattended vehicle deliveries, and alarm verification using the video management system. Video Surveillance System Maintenance and Evaluation Maintenance is best performed by a competent on-site staff member with an electronic system troubleshooting background who also understands the components and complexity of the system used in the original system design. Equipment logs should be maintained, and the manufacturer\'s equipment documentation should be kept onsite and in a central storage location. Camera adjustments consume most of the maintenance time-optical focusing of the lens is a major factor during installation of the cameras. Depending on the budget allocations and needs, approximately 5 percent of spare parts are recommended to be kept on hand. It is also important to maintain environmental factors such as trimmed bushes and tree limbs because they may block the cameras field of view. Video System Evaluation and effectiveness is based upon these factors: ·Minimum time between sensor alarm and video display ·Complete video coverage of the detection zone ·Ability to clarify a 1 ft. (0.3 m) target at the far edge of the assessment zone ·Vertical field of view at the far edge of the detection zone (i.e. a person climbing over a standard fence height) ·Continuous operation 24/7/365 ·Minimal sensitivity for each camera to environmental conditions ·Minimal obstruction of the assessment zone (vegetation and trees, fences, boxes, furniture, etc.) ·Camera field of view and video recording integration with intrusion detection (displays alarm source to an operator automatically). Video Surveillance Notes of Interest ·Cold weather below 35 degrees F (1.7 degrees C) may require a heater inside the camera housing. ·Warm weather above 80 degrees F (26.7 degrees C) may require a fan/blower inside the camera housing. ·A camera installed in a sunny area may require a sun shield and/or if installed facing east or west, a sun visor over the lens to cut the glare. ·For proper security viewing a camera should not view more than two objectives (one major and one minor). ·A camera should not auto-pan more than 45 degrees to the left or right from the center of its major focus. ·Camera installation should be evaluated against 1) the manufacturer\'s specifications, 2) compatibility with the design criteria, and 3) consistent performance from camera to camera. ·Camera selection should be primarily based on sensitivity for full video output signal in the lighting environment. ·Smaller camera formats reduce sensitivity and lower resolution, but typically cost less than larger format cameras. ·Mounting a C lens into a CS camera without an adapter ring will crack the CCD (CS cameras moved the CCD 15mm closer to imager). The standard distance between a CS lens and sensor is 12.5mm. ·A CS mounted lens in a C type camera will not be in focus. The standard distance between the sensor and the C lens is 17.526 mm. ·Auto Circuit/Electronic Current (AC/EC) lens produced prior to 2002. ·Direct Circuit/Logic Control (DC/LC) has become the industry standard. Since 2002 cameras only accept the industry standard DC/LC lens. ·Mounting a 4 CIF megapixel lens on a 1.3-megapixel camera would focus the image on 4 pixels, rather than just one pixel. The result is wasted technology, money, and effort. ·When running a camera more than 1,000 feet (304 m) from the controls, a fiber optic cable should be used, regardless of the type of camera being installed. ·Encryption should be used to protect communications from the camera to the controls for both wired and wireless transmissions of imagery. This may adversely affect the speed of image transfer. ·Coaxial cabling (RG-59) uses BNC (British Naval Connectors, also referred to as Bayonet-Neill-Concelman Connectors) to connect the coaxial cable from the camera to the recording medium. ·Twisted-pair cables are typically network cables using CAT-5, 5E,6E, or 7cabling and can be run a maximum distance of 328 feet (100m) before amplification is required. ·Parking facility cameras should be placed with an unhindered view (good lines of sight) to cover as much ground as possible and should be protected by vandal resistant dark polycarbonate domes. ·Low light cameras can be used in applications, but they are expensive and may indicate that the lighting sources in these areas are poor. ·Parking facilities that have video surveillance coverage should be monitored in real-time and digitally recorded for playback and enhancement. Color cameras should be used to identify specific vehicles and clothing. Cameras should also be positioned to capture license plates when vehicles enter or exit the area. Panic buttons should be installed with integrated video surveillance. ·Video surveillance for clear zones should display as much as possible of the clear zone, including the inner and outer fences. \- Require uniform inner and outer fence spacing \- Use minimum width restrictions for clear zone \- Remove vegetation and grading of the ground \- Provide adequate illumination ·Exterior assessment zones should have one fixed camera per zone for assessment purposes. The speed of the camera system should be tested and should be adequate enough to capture the intrusion event-someone running through the zone, a vehicle driving through the zone, etc. ·Video analytics can be 1) preprogrammed, or 2) learning algorithm. ·When using video analytics for integration with seismic-type alarm sensors, the tower height and location should be such that it reduces pole vibrations due to wind. It is also important to reduce pole vibrations when using video surveillance analytics such as video motion detection. ·Intelligent video is a learning algorithm that processes and evaluates the camera image for a period of time, and develops a sense of normal behaviors and environmental conditions such as traffic patterns, weather, evening/daytime, behaviors, speed and direction, normal image patterns, movement of trees and vegetation, etc. ·A test for camera resolution is to use appropriately sized targets for identification in the assessment zone-a triangle, square or circle that is 1foot (0.3 m) in size and painted black on one side and white on the other. These shapes should be placed at the furthest part of the assessment field and the operator should be able to view and recognize each shape. Using 1-foot (0.3m) shapes is supposed to simulate a person crawling. ·Video surveillance monitoring by an operator is most effective during the first 20 minutes of watching a monitor. Operators are typically better at assessment, not the detection function. Use of video analytic and content analysis can assist the operator. ·Distributed intelligent video has the intelligence distributed to the edge devices and resides in the camera or video encoder. Conversely, in a centralized intelligent video system, all of the intelligence resides in the server.