Xtralis ADPRO Presidium, Инструкция по установке и эксплуатации

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Installation and User Manual ADPRO Presidium by Xtralis
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Doc. 12384_05
2.4 Presidium System Concept
This section provides a brief description of how Presidium performs image processing to
determine if an intruder is present in the protected area.
2.4.1 Operational Concept
Presidium analyses video from CCTV cameras to detect movement that is likely to be an
intruder. A number of criteria, used in conjunction with complex image processing routines, are
used to distinguish between an intruder and some other form of movement. The same
techniques are used to reduce other factors such as changes in contrast from shadows cast by
clouds and moving trees.
Presidium monitors contrast changes and rate of contrast change within the defined detection
areas. This information on contrast changes and rates of change is fed into a number of
computational routines that analyse the changes and extract valid targets from the images whilst
rejecting changes from background movement. The detected targets are further analysed to
ensure that they meet criteria based on size and speed. If the criteria is met, an alarm is
generated.
What is actually considered a target will depend on your particular security requirements. In a
high security environment, the maximum horizontal Field of View (FOV) should be less than for
that in a medium security environment.
2.4.2 Basic Parameters
To achieve high detection probability and effective nuisance alarm rejection, the field of view at
the maximum detection distance should be no more than 16.7 times the target size.
For example, to detect a 1.8m high human target, the recommended maximum field of view at
the maximum detection distance is:
FOV = 16.7 x 1.8m = 30m
If a larger field of view is used, then the detection probability is reduced.
In this scenario, increasing Presidium's sensitivity can only partially compensate for the reduced
detection probability and may lead to an increase in the number of false alarms. It is not
recommended.
The maximum horizontal FOV, and the required target size to be detected determines the
required camera and lens configuration.
2.5 System Design
The system design phase consists of three elements:
• Preliminary Information : Gather general site information and discuss the security
requirements with the customer to ensure that the Presidium meets the customer's
requirements.
• Site Survey : Conduct a site survey to determine site requirements such as the positioning
of cameras and other detectors, lighting, and existing and required communications
infrastructure.
• Equipment Selection : Conduct a comprehensive analysis to determine equipment
requirements, such as camera types and lenses, level and type of illumination, and
communications and control room equipment.