MOTION DETECTION

Motion detectors can use a number of kinds of sensors to note changes. They fall into five major sensor types and may be active or passive. Passive Infrared (PIR) are the most common, sensing shifts in infrared energy levels. Photoelectric (PE) are active sensors, as they emit a beam that triggers when interrupted. With a separate receiver/reflector unit, they may monitor the differences between emitted and received light energy. Infrared laser sensors (Laser) are similar, but more powerful, as they emit and monitor precise fields of energy and can be adjusted in width and distance. They also work in the dark and can pick up infrared signals from body heat. Tomographic sensors broadcast radiation across a large area monitor movement. They tend to operate in a mesh of networks and offer the added benefit of detecting through non-organic fixed objects, like windows and walls.

As sensors using only one detection method are prone to error, many motion sensors employ multiple detectors. Doppler /Microwave sensors (Multi-Tech) use reflected energy or sound waves to trigger and tend to work better when coupled with a PIR system.

Object movement detection using cameras can be accomplished through the reading the changes in pixels, in background modeling or using motion vectors. Also known as motion tracking, it may be set for all objects or set to only include people.

Embedded lighting modes allow for 24-hour consistency of response. It is also possible to preset interval settings for time-within-areas, meaning an alarm may only be triggered if a person is loitering as opposed to merely walking by. To minimize false alarms triggered by clouds, trees and shifting from night-to-day, ‘smart detection’ is based on accessing human silhouette databases. Motion tracking offers energy conservation by activating lighting, turning on and off water faucets, hand driers, heating or air conditioning.

Motion Detection may be linked to other access systems and to open and close doors. Adjustable aspects include motion, detection interval, resolution and keyframe only. Features include an alarm manager, one or two audio support, and preset patrol parameters.