Variable EAS Detection Algorithm for High-Speed Passage
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Solution Overview
Problem
Conventional Electronic Article Surveillance (EAS) systems fail to detect AM markers effectively when individuals pass through the surveillance zone at high speeds, as the detection process requires a fixed time duration that exceeds the time spent by fast-moving individuals, leading to missed detections.
Innovation Solution
A variable EAS detection algorithm is implemented based on the speed of individuals passing through the zone, adjusting the detection criteria to reduce the rigor of the algorithm when high speeds are detected, allowing for quicker alarm generation and improved detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed time duration detection process is used, then detection reliability is improved for slow-moving individuals, but detection capability deteriorates for fast-moving individuals who pass through the zone too quickly
Solution Approach 1:
The patent applies dynamics by transitioning from a static, fixed-time detection process to a dynamic, speed-adaptive detection process. The system continuously monitors the time of flight (TOF) of individuals through the surveillance zone and adjusts the detection algorithm's required signal count accordingly. When faster movement is detected, the system reduces the required number of signals, allowing the detection criteria to adapt in real-time to varying speeds while maintaining reliable detection across different movement scenarios.
2Reliability
If the detection algorithm rigor is increased to reduce false alarms, then false alarm rate is improved, but detection sensitivity deteriorates for fast-moving individuals
Solution Approach 1:
The patent applies parameter changes by modifying the detection algorithm's critical parameters based on measured movement speed. Specifically, the system changes the required signal count threshold dynamically. When individuals move faster than a predetermined speed threshold, the system reduces the required signal count, thereby lowering the detection barrier and maintaining sensitivity. This parameter adjustment allows the system to maintain both low false alarm rates and high detection sensitivity across varying speeds.
3Device complexity
If a fixed detection time duration is used, then system simplicity is maintained, but productivity deteriorates due to missed detections during high-speed passages
Solution Approach 1:
The patent applies feedback by implementing a closed-loop system that continuously monitors the time of flight (TOF) of individuals through the surveillance zone and uses this information to adjust detection parameters in real-time. The system measures actual movement speed and feeds this information back to modify the required signal count threshold. This feedback mechanism allows the system to maintain high detection effectiveness without requiring complex pre-programmed responses for different speed scenarios, preserving relative simplicity while dramatically improving productivity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The variable algorithm enhances the likelihood of detecting EAS tags and reduces false alarms by adapting to varying speeds, effectively addressing the issue of missed detections during high-speed passages and potentially preventing shoplifting.
Implementation Method 1
An exciter coil is used to generate an electromagnetic field within a surveillance zone
Implementation Method 2
a response is detected to the electromagnetic field caused by one or more objects within the surveillance zone
Data Source
Figure 1~2
Figure 3A~3B
Figure 4A~4B
AI summary
In an Electronic Article Surveillance ("EAS") system a response is detected to an electromagnetic field. The response is caused by one or more objects present within the surveillance zone and an alarm condition is then selectively generated in accordance with one or more detection algorithms. A speed of a person traveling through the surveillance zone is measured, and if the speed exceeds a threshold then at least one characteristic of the detection algorithm(s) is varied to decrease a rigor of the detection algorithm.