Optical Motion Sensor Background Adjustment for False Alarm Filtering
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Solution Overview
Problem
Conventional optical motion sensors are prone to false positives due to abrupt light illumination changes, such as room lights switching on/off or sunlight changes, which can lead to incorrect detection of motion.
Innovation Solution
An optical motion sensor system that includes a sensor circuit with a pixel array and a processing circuit capable of performing a background adjustment operation. The processing circuit calculates short-term and long-term averages of pixel values and generates a preliminary alert signal when the variance between these averages exceeds a threshold, indicating a potential false alarm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional optical motion sensor uses pixel difference threshold for motion detection, then motion detection is achieved, but false positive results occur due to abrupt light illumination changes
Solution Approach 1:
The patent applies preliminary action by performing background adjustment operations before motion detection. The system pre-calculates background images and adjusts them proactively to account for anticipated light changes, rather than reacting after false positives occur. This is achieved through the processing circuit that continuously updates background reference images based on historical data and detected patterns of environmental changes.
Solution Approach 2:
The patent introduces an intermediary mechanism - a background adjustment layer - that mediates between the raw sensor input and the motion detection algorithm. This background adjustment process acts as a buffer that absorbs the impact of abrupt light changes, preventing them from directly triggering false motion detections. The background image serves as an intermediary reference that is dynamically adjusted to match current lighting conditions.
2Reliability
If optical motion sensor adjusts background dynamically to reduce false alarms, then false positive reduction is achieved, but processing complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the pixel array into multiple zones or regions, each with its own background adjustment parameters. Instead of processing the entire image uniformly, the system segments the scene and applies localized background adjustments to different areas. This reduces the overall processing complexity while maintaining effective false alarm reduction in each segment.
Solution Approach 2:
The patent changes parameters dynamically - specifically, it adjusts background reference values and threshold parameters based on detected environmental conditions. The processing circuit modifies detection parameters adaptively rather than using fixed thresholds, which reduces false alarms without requiring proportionally complex hardware. The parameter changes are computed through algorithms that balance accuracy with processing efficiency.
Data Source
AI summary
A method of identifying a false alarm of an optical motion sensor including a plurality of pixel units, includes: receiving pixel values of a testing set of pixel units selected from the plurality of pixel units, and a number of pixels of the testing set is smaller than a number of the plurality of pixel units; and performing a background adjustment operation according to the pixel values of the testing set of pixel units.