Optical Sensor Dynamic Threshold for Ambient Light Noise
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Solution Overview
Problem
Existing optical sensors for detecting objects in surveillance areas suffer from reduced sensitivity due to extraneous light noise, as they are typically set to handle maximum external light exposure, leading to wasted sensitivity in situations with lower light exposure.
Innovation Solution
The method and optical sensor dynamically adjust the evaluation threshold and comparison signal based on the extraneous light component, increasing sensitivity by accounting for external light conditions, allowing the comparison signal to be amplified or the threshold adjusted accordingly, thereby optimizing signal-to-noise ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the evaluation threshold is set to handle maximum external light exposure, then the sensor can operate reliably under high extraneous light conditions, but the sensitivity is reduced and wasted in situations with lower light exposure
Solution Approach 1:
The patent implements dynamic adjustment of the evaluation threshold based on the actual extraneous light component detected by the receiving unit. The control unit continuously monitors the extraneous light level and adapts the threshold accordingly, transitioning from a static threshold set for maximum light conditions to a dynamic threshold that optimizes sensitivity for current lighting conditions while maintaining reliability when extraneous light increases
Solution Approach 2:
The patent changes the evaluation threshold parameter based on the detected extraneous light component. By monitoring the actual light conditions and adjusting the threshold parameter dynamically, the system optimizes its detection sensitivity for varying external light exposure while maintaining reliable operation across different environmental conditions
2Reliability
If a fixed evaluation threshold is used to prevent false positives from extraneous light noise, then false detections are avoided, but the sensitivity is suboptimal in varying light conditions
Solution Approach 1:
The patent implements feedback by having the receiving unit continuously monitor the extraneous light component and feed this information back to the control unit. The control unit then adjusts the evaluation threshold based on this feedback, creating a closed-loop system that adapts to changing light conditions and maintains optimal detection performance while preventing false positives
Solution Approach 2:
The system transitions from a static evaluation threshold to a dynamic one that adapts in real-time based on monitored extraneous light levels. This dynamic adjustment allows the sensor to maintain low false positive rates while optimizing sensitivity for current lighting conditions
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
This approach enhances sensitivity by up to a factor of 10, with significant improvements in signal-to-noise ratio, achieving better performance in varying light conditions without triggering false positives from noise.
Implementation Method 1
a receiving unit for detecting light reflected back from the surveillance area
Data Source
Figure 1~2
Figure 3
AI summary
The invention relates to a method for detecting objects in a monitoring area, in which a transmitting unit emits oscillating light into the monitoring area, in which a receiving unit detects light reflected from the monitoring area, in which at least an oscillating component of a received signal from the receiving unit is amplified for evaluation purposes, and in which a detection signal is emitted when a comparison signal derived from the received signal of the receiving unit is greater than a defined evaluation threshold. The method is characterized in that an ambient light component arriving at the receiving unit is taken into account during the evaluation, that the evaluation threshold is raised with increasing ambient light component, and/or that the comparison signal is increased by a factor that decreases with increasing ambient light component.The invention also relates to an optical sensor for detecting objects in a monitored area.