Motion Detector Hum Noise Classification via Frequency Analysis
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Solution Overview
Problem
Existing motion detection systems, particularly those using Doppler sensors, are vulnerable to false positives due to hum-type noise, requiring separate vibration sensors, increasing complexity and cost, and struggling to differentiate between mechanical and electrical hum noise sources.
Innovation Solution
A motion detection system that integrates hum noise detection directly from the motion sensor's output, using frequency domain analysis to identify noise-caused frequency bins and classify the environment as motion or quiet, eliminating the need for separate vibration sensors and improving sensitivity to distinguish between noise and actual motion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate vibration sensor is added to detect hum noise, then the reliability of motion detection is improved, but the device complexity increases
Solution Approach 1:
The patent extracts the hum noise detection function from a separate vibration sensor and integrates it directly into the motion sensor's signal processing path. By analyzing the frequency spectrum of the motion sensor output directly, the system identifies hum noise characteristics without requiring a dedicated vibration sensor, thus maintaining reliability while reducing complexity
Solution Approach 2:
The patent merges the motion detection and hum noise detection functions into a single integrated system. The motion sensor simultaneously performs both motion detection and hum noise identification through frequency domain analysis, eliminating the need for separate sensors and reducing overall system complexity
2Measurement precision
If the motion sensor sensitivity is increased to detect true motion, then the detection precision is improved, but the number of false positives from hum noise increases
Solution Approach 1:
The patent applies local quality by analyzing specific frequency bands within the motion sensor output. By identifying and isolating the frequency characteristics of hum noise through spectral analysis, the system can locally filter out these harmful frequencies while maintaining sensitivity to true motion signals across other frequency ranges
Solution Approach 2:
The patent converts the harmful hum noise signal into a beneficial filtering mechanism. By analyzing the frequency spectrum of the motion sensor output, the system identifies hum noise patterns and uses them to create exclusion criteria that filter out false positives, turning the noise problem into a solution for improving detection accuracy
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 system effectively reduces false positives by directly detecting hum noise from the motion sensor output, enhancing the detection of true motion while reducing system complexity and cost, and addressing the limitations of existing systems in handling both mechanical and electrical hum noise sources.
Implementation Method 1
The motion sensing unit is a microwave (RF) Doppler sensor that uses the Doppler effect to detect a motion by detecting a wave generated by a wave source
Data Source
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Figure 3c~3d
AI summary
Some embodiments are directed to a motion detector configured to classify an environment as quiet or motion. The motion detector is configured to estimate if the frequency bins in a motion signal correspond to a motion source in the environment or to a noise source in the environment. Some embodiments are directed to a luminaire comprising a motion detector.