Vehicular Reflective Optical Sensor Dynamic Threshold
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Solution Overview
Problem
Conventional vehicular foot detection systems face reliability issues due to varying optical environments and brightness, leading to inconsistent light reflection and decreased detection accuracy.
Innovation Solution
A vehicular reflective optical sensor with a control unit that adjusts the detection threshold based on preceding light reflections, incorporating a fixed value and a statistically calculated adjustment value, and performs noise checks to improve detection accuracy and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a fixed detection threshold is used for foot detection, then the device complexity is low, but the detection accuracy deteriorates due to varying optical environments and brightness at different stopped locations
Solution Approach 1:
The detection threshold is transformed from a fixed value to a dynamic value that automatically adapts to changing optical environments. The control unit calculates the detection threshold based on the luminance of the detection region, allowing the threshold to vary with environmental conditions such as brightness and stopped location, thereby maintaining high detection accuracy without requiring manual adjustment
Solution Approach 2:
The system performs self-calibration by automatically measuring the luminance of the detection region and computing the appropriate detection threshold without external intervention. The control unit uses the captured image data to determine the average luminance and sets the threshold accordingly, enabling the system to adapt to different optical environments autonomously
2Reliability
If moving average values of multiple light reflection data are used, then the influence of noise is reduced, but the detection accuracy still deteriorates due to changes in the detection environment
Solution Approach 1:
The fundamental parameter for threshold determination is changed from fixed or statistically averaged light reflection values to luminance-based threshold calculation. By using the luminance of the detection region (derived from captured images) as the basis for setting the detection threshold, the system adapts to environmental changes such as varying brightness and optical conditions, maintaining both noise resistance and detection accuracy
3Measurement precision
If the detection threshold is adjusted based on preceding light reflections, then the detection accuracy improves by accounting for environmental changes, but the device complexity increases due to statistical processing requirements
Solution Approach 1:
The system replaces complex statistical processing of light reflection data with a simpler luminance-based threshold calculation. Instead of analyzing multiple light reflection values and computing moving averages, the control unit directly uses the luminance information from captured images to determine the detection threshold, reducing computational complexity while maintaining 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 maintains high detection accuracy and reliability by dynamically adjusting the detection threshold to account for changes in the optical environment, reducing noise interference and improving operation reliability.
Implementation Method 1
a light-emitting unit (2) that emits detection light (3) at prescribed intervals towards a detection region (1) set outside the vehicle; a light-receiving unit (5) that receives light reflection (4) from the detection region (1)
Data Source
Figure 1(a)~1(c)
Figure 2
Figure 3
AI summary
The purpose of this invention is to provide a vehicular reflective optical sensor that has improved control reliability. Said vehicular reflective optical sensor is provided with a control unit (6) that: emits detection light (3) at prescribed intervals from a light-emitting unit (2) on an exterior panel of a vehicle towards a detection region (1) set outside said vehicle; tests for a threshold-exceeded state in which the amount of light in a light reflection (4) received from the detection region (1) by a light-receiving unit (5) exceeds a prescribed detection threshold; and, if it is detected that a detection target has entered the detection region (1), outputs a detection-confirmation signal. The control unit (6) uses, as the aforementioned detection threshold, the sum of a predetermined fixed value and an adjustment value comprising a summary statistic for the amounts of light in an appropriate number of light reflections (4) preceding the light reflection (4) on which the comparison is being performed.