12 – Alarm Assessment

The Twenty-Seventh International Training CoursePage 1

12. A larm Assessment SystemApril 29 – May 18, 2018

Albuquerque, New Mexico, USA

Alarm Assessment

Learn ing Object ives

After completing this module, you should be able to:• Discuss the function of alarm assessment• Define important video camera features• Recognize impact of individual system components• Describe video assessment system design principles that

have been used successfully• Describe design considerations for lighting placement

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Alarm Assessment

IAEA Nuclear Secur i ty Ser ies 13 (NSS-13)

• 4.15. Provision should be made for detecting unauthorized intrusion and for appropriate action by sufficient guards and/or response forces to address a nuclear security event.

• 5.36. A permanently staffed central alarm station should be provided for monitoring and assessment of alarms, initiation of response, and communication with the guards, response forces, and facility management

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Purpose of A larm Assessment System

• Determine cause of each sensor alarm in a timely manner

• Provide information about an intrusion to response force• Complete the detection process

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Note: Detection without Assessment is not Detection

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Types of Assessment

• Personnel Assessment by on-site personnel

• Guards or security officers• Local law enforcement (police)

• Technology Assessment via video display at

Central Alarm Station

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Assessment Des ign

• Must be interactive with sensor design Must cover entire sensor detection volume Should be able to see adversary climbing over fence or sensor at

end of detection zone Place more even sector lengths on a perimeter side, as that

works best for video design• Consider moving a sector boundary

It could improve layout Allow more efficient use of camera towers and infrastructure

• May need interior cameras in entry control portals Identification rather than classification

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Alarm Assessment

Components of Assessment System

• Complete system composed of Lenses, sensors, signal processing, network / bandwidth constraints,

Video Management System, monitors, and human brain• Any of these elements can be a bottleneck in system performance

Imager sensor may not have enough pixels on target at given field of view

Network bandwidth limits may require increasing compression of video stream, which effectively reduces pixels on target

Monitor may have too few pixels to support multiple cameras Human may be tired, distracted, overwhelmed, etc.

• Assessment system only as good as the weakest element7

Camera Trade-Offs

• Video Assessment vs. Surveillance Video assessment is presented after an alarm to allow the

operator to determine the cause of the alarm Surveillance is used to monitor activity and relay the real-time

level of information for the response force• Fixed cameras vs. Pan-Tilt-Zoom Cameras

Fixed cameras - used for video assessment• Are always pointed at the assessment zone• Allow for pre-alarm and post-alarm recordings

PTZ cameras - used for surveillance and have a capability to swivel from one point to the other

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Camera Trade-Offs (cont ’d)

• Color cameras vs. Black-and-white cameras Color enhances daylight scenes Color at night

• Gold-brown images with sodium vapor lamps Standard color camera resolution 18% less than black and white Black-and-white camera images provide higher resolution,

sensitivity, contrast, brightness, and sharper night image

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Camera Def in i t ionsFocal length – Distance from the lens to the camera imager when the lens is focused at infinity

Aperture – Adjustable opening that controls the amount of light to the imager; can be fixed or adjustable (f-stops)

Depth of field – Portion of the image that is in sharp focus; greater at higher f-stops and smaller focal lengths

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Object Distance

Focal Length

F22 F4 F1.4

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Camera Def in i t ions (cont ’d)

Field-of-view: Horizontal and vertical distances visible in the camera image at a linear distance from the camera

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Levels of Resolut ion

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Detection Classification Identification

Determine the presence of an 

object

Determine what an object is

Determine the identity of the 

object

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Monitor V iew of an Assessment Zone

• Each assessment zone (interior or exterior) should be Centered on

the monitor Occupy

approximately 75% of the monitor area

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Far Field

Assessment Zone

Near Field

Geometry of Assessment Zone

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Video Camera Des ign Requirements

• Minimum time between sensor alarm and video display• Complete coverage of intrusion detection zone and

sensors• Classify 30-cm target at far edge of detection zone• Continuous operation 24 hours per day, 7 days a week• Minimal sensitivity to adverse

weather conditions• Cameras tilted down so horizon

not in field-of-view

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V ideo Camera Types and Housings

• Dome cameras• Do not have ability to add sunshield to prevent glare in lenses

• Clamshell housing• May allow fine dust in

• Can destroy auto-iris lenses

• Pressurized housings• Require pressurization with nitrogen gas

• Heaters are recommended to prevent condensation on front glass

• Infrared LED illuminators in camera housings are not adequate for illuminating the PIDAS views

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Video Disp lay and Recording

• Video display for operator at CAS contains what is most important for making correct alarm assessment

• Resolution could be degraded by Monitor resolution Recording method Compression Transmission system

• Time is critical for assessing alarms • Operator should not have to search for recording of

alarm video

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V ideo Considerat ions

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Video Assessment Component

Consideration

Lenses Format (must match camera type), focal length, F‐stop, IR filters, or correction

Camera Light sensitivity, resolution, analog or IP, auto‐Iris or electronic shutter, housing, imager, imager format

Lighting Lamp type, restrike time, luminaire, pole, height

Camera Tower Type, location, height

Signal Transmission Type, bandwidth, network concerns

Video Recorder Network Video Recorder, Digital Video Recorder, storage requirements, frame rate, compression, ease of retrieval and playback, pre‐ and post‐alarm

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Video Transmiss ion

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Transmission Type

Description

Coaxial Cable Requires signal conditioning, surge protection separation from power lines; 

May require amplification for longer distances

Fiber Optic Cable Requires active componentsIs immune to noiseCan transmit over longer distances

Twisted Pair Low bandwidth Resolution may be reduced

Ethernet Cat 5 or Cat 6 limited distances May have network connections outside secure area

Wireless Line of sight required, can be jammed

Alarm Assessment

Impact of Indiv idual System Components

• Linear process – Can be constrained by any individual element

• Camera type, lens, imager detector number of pixels, compression / bandwidth, monitor number of pixels all impact detection, classification, and identification values

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Design Requirements for Camera Towers

• Camera mount and tower stable in wind Even more critical if considering video

motion detection or video analytics• Camera tower does not interfere with

sensor operation • Camera tower does not obscure view of

assessed area• Wooden poles will twist as they dry out

and result in changes to camera aiming

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Camera Tower Des ign Considerat ions

• Camera tower location in PIDAS Consider:

• Sensor defeats• Possible tampering • Blind spots • Network concerns

• Camera height Placement 8 to 10 meters typically prevents

view of horizon Lights 2 to 3 meters higher than cameras

• Camera maintenance

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Layout Des ign

• Skip sectoring – Camera towers located at sector boundaries

• Terrain – Avoid aiming cameras towards sky• Avoid cameras outside of PIDAS

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L ight ing Design Requirements

• Minimum lighting intensity Average minimum is 1 foot-candle (10 lux)

• Uniform illumination Light-to-dark ratio of 6:1 (maximum) Design goal of 4:1 Minimum scene reflectance 30% when dry

• Extent of coverage Minimum of 70% field-of-view

• Camera sensitivity must be adequate to work properly with these light levels

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6:1

24:1

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Light ing Des ign Considerat ions

• Lamp type• Color balance• Restrike time• Efficiency• Response force prefer lights inside PIDAS• Lighting design programs available from

manufacturers

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V ideo Assessment Des ign Pr inc ip les

• Use fixed cameras for assessment• Integrate video assessment with alarm display system• Place one camera per sector• Ensure lights always on (at night) instead of turned on

after alarm• Place lights higher than the cameras• Mount cameras high, looking down• Use skip sectoring

Camera looks at next sector• Do not use wooden poles for camera mounting

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Key Takeaways

• Assessment design Must be interactive with sensor design Consider moving a sector boundary

• Camera design Minimize time between sensor alarm and video display Have complete coverage of intrusion detection zone and sensors

• Camera tower design Ensure towers do not interfere with sensor operation Ensure towers do not obscure view of assessed area

• Lighting design Minimum lighting intensity - 1 foot candle (10 lux) average Camera sensitivity must work properly with different light levels

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