Motion Detectors

Motion Detectors

Copyright: © 2014 |Pages: 21
DOI: 10.4018/978-1-4666-4896-8.ch023
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Abstract

The first five sections represent the foundation and offer various intelligent algorithms that are the basics for motion detectors and their realization. There are two classes of security system alarm triggers: physical motion sensor and visual motion sensors. Both analog motion detectors and digital motion detectors belong to the group of visual motion sensors. Digital motion detector systems should differentiate between activities that are acceptable and those that breach security. When security-breaching acts occur, the system should identify the individuals and instruct security personnel what to do. Motion detectors can surveil, detect, and assess, as well as analyze information and distribute information to security personnel. Motion detector systems drastically reduce the load of footage that guards must watch for a long period of time. Automated motion detectors are now a standard for serious medium to large security installations; they are necessary for high detection capabilities. All security systems must have an alarming device to signal the guard of irregular motion in a scene, even systems that have a tiny or huge number of cameras.
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1. Introduction

There are two classes of security system alarm triggers. One class is the physical motion sensor: simple contact switches and pyroelectric infrared PIR sensors. These systems recognize only movement, but are varied in terms of their technologies and operations. The other class is visual motion sensors: human guards count in this category, as well as both analog motion detectors AMVD and digital motion detectors DVMD.

Digital motion detector systems should differentiate between activities that are acceptable and those that breach security. When security-breaching acts occur, the system should identify the individuals and instruct security personnel what to do. In order to accomplish these tasks, a digital motion detectors system utilizes physical monitors or real-time/time-lapse video cassette recorders VCRs and digital video recorders DVRs.

Video security systems are necessarily comprised of these four components:

  • 1.

    Surveillance.

  • 2.

    Detection.

  • 3.

    Assessment.

  • 4.

    Response.

Motion detectors can inform all four of these components, even the response mechanism. They can surveil, detect, and assess, as well as analyze information and distribute information to security personnel (Kruegle, 2007). Additionally, the motion detector encourages security personnel to train and develop their response philosophies.

Automated motion detectors are now a standard for serious medium to large security installations; they are necessary for high detection capabilities.

Innovations in the digital signal processing DSP field have made motion detectors much more available and affordable, and have also improved the quality and capabilities of simple, first generation analog motion detectors.

In short, the advancement of DSP allows for the integration of intelligence into digital motion detector technology. Digital motion detector systems are a combination of motion detection and the visual representation thereof. Motion detector systems equipped with intelligence utilize complex DSP algorithms to make them responses to changes in the scene instead of presenting false alarms. This is a huge improvement upon previous technologies.

For example, digital motion detectors with intelligence can come with a huge amount of presets, such as the overlooking of tree branches, rain, dust, and other environmental factors that would have thrown off previous motion detector systems. Security footage that is deemed useful is often of moving objects, vehicles, and people, or otherwise captures activities with motion. This is the type of information that is eventually shown on a security monitor.

All security systems must have an alarming device to signal the guard of irregular motion in a scene, even systems that have a tiny or huge number of cameras.

Although motion detector systems drastically reduce the load of footage that guards must watch, medium and large security video installations often generate too much video for one security guard to watch for a long period of time.

Video multiplexers address this issue: they decrease the number of physical monitors to which the guard must be paying attention, which increases the guard’s capability to react in real-time. Ultimately it is the motion detector that analyzes the camera footage for alarm-worthy events, which alert the security officer. This technology frees the security guard for other tasks while it monitors the scene at which it points. It alerts the guard of suspicious situations.

These systems work within the camera’s field of view FoV in order to detect abnormalities in the area. This task is performed by analyzing the difference between pixel light levels from one frame to the next; the motion detector system notices significant changes.

Analog motion detector systems, which are simpler and cost less compare larger areas in a frame to the preceding frame. These systems are satisfactory in situations that have consistent lighting and few changes. This type of scene is almost always found indoors.

Analog systems are not recommended for outdoor installations because they are extremely sensitive to changes in light, natural objects passing through the field of view FoV, animals, water movement, and general vibration. Digital motion detectors should be used outdoors instead.

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