Signal analysis is critical for the motion detector, which receives a minimum of information about the object in the protected area due to the 4,5° horizontal field of view. Precise analysis ensures quick response to humans, eliminating reaction on animals and natural interferences.
DualCurtain Outdoor uses ELSA, a three-step software algorithm that analyzes the signals from two narrowly focused PIR sensors of the optical system.
1. Form analysis
The PIR sensors’ signal waveforms must correspond to the way an intruder crosses the protected area. In any direction: perpendicular or along the direction of the detection area. At the same stage, a correction for the signal intensity is made, in order to take into account the distance from the sensors and the dimensions of the object.
2. Patterns comparison
The signal amplitudes are verified against the pattern database. To create it, we analyzed thousands of curtain detector triggerings on people, animals, lights, and other natural interferences in various weather conditions. The signals must match the patterns that are typical for humans.
3. Time verification
When signals from both PIR sensors match the conditions — this is motion, and it is typical for a human — ELSA compares the time intervals when the signals received, determining whether the upper and lower sensors detected motion synchronously.
To reach a verdict whether it’s a threat or false alarm, ELSA needs less than a second.
Efficiency in the near area
DualCurtain Outdoor features a technology to expand the protected area, which is unique among outdoor curtain motion detectors. When Near Area Detection is enabled, the detector’s upper PIR sensor receives an additional narrow viewing sector directed at the angle of 40 degrees down against the main sector. The feature allows both sensors to detect movement when a human crosses the protected perimeter closely to the detector’s body, addressing the problem of the blind spot, which is a typical problem of such detectors.
Near Area Detection is designed to protect windows and other passages that animals have no access to. The proximity of the detection zones’ vectors significantly reduces the efficiency of pet immunity.
Near Area Detection technology is supported by both Dual Curtain Outdoor optical systems