Variable Message Sign Detection Using Position-Based Parameter Adaptation
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Solution Overview
Problem
Variable message traffic signs, which use pulsed LED lights, are difficult to detect due to their frequency being imperceptible to the human eye, leading to incomplete or undetectable images, especially when the pulsing phase aligns with camera exposure times, requiring inefficient longer exposure times or multiple exposures.
Innovation Solution
A method that utilizes known geographic positions of variable message traffic signs to adapt detection parameters, such as exposure time and image evaluation, by providing proximity information to optimize detection, including varying detection instructions based on the sign's position, elevation, and pulsing frequency, allowing for efficient resource use by applying specialized detection methods only when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If longer exposure times or multiple exposures are used to detect variable message traffic signs, then detection reliability is improved, but productivity decreases due to increased processing time and resource consumption
Solution Approach 1:
The system performs preliminary actions by using geographic position data from digital maps to predict the location of variable message traffic signs before actual detection. This allows the system to prepare detection parameters in advance and only apply specialized detection methods when a sign is expected, rather than continuously using resource-intensive detection approaches.
Solution Approach 2:
The detection parameters are made dynamic and adaptive based on the vehicle's position relative to expected sign locations. The system adjusts exposure time, image recording frequency, and detection algorithms in real-time based on proximity information, using longer exposure times only when a variable message traffic sign is anticipated in the current location.
2Measurement precision
If specialized detection methods are applied continuously to detect variable message traffic signs, then detection precision is improved, but device complexity increases
Solution Approach 1:
Different detection methods and parameters are applied locally based on spatial information. The system uses specialized detection algorithms and adjusted exposure times only in geographic areas where variable message traffic signs are expected, while using standard detection methods elsewhere, thereby reducing overall system complexity.
Solution Approach 2:
The detection system is designed to handle multiple types of traffic signs using a unified framework. The same image recording device and processing system detect both conventional traffic signs and variable message traffic signs, with the ability to switch between detection modes based on location data, reducing the need for separate specialized systems.
3Use of energy by moving object
If the camera image recording frequency does not align with the LED pulsing frequency, then energy consumption is reduced, but detection reliability worsens due to missed signs
Solution Approach 1:
The system uses preliminary geographic position information to anticipate the presence of variable message traffic signs before actual detection occurs. This allows the camera to adjust its image recording frequency and exposure timing in advance to match expected sign locations, ensuring reliable detection without continuously operating at high energy consumption levels.
Solution Approach 2:
The camera parameters such as exposure time and image recording frequency are dynamically changed based on the vehicle's position relative to expected sign locations. When approaching a known sign location, the system adjusts parameters to optimize capture of the pulsed LED signals, and returns to lower energy consumption modes when signs are not expected.
Data Source
AI summary
A method for detecting variable message traffic signs for a vehicle, includes: reading in a vehicle position, comparing the vehicle position to position information of at least one variable message traffic sign in order to determine a presence of a variable message traffic sign in a predefined area around the vehicle and in response to provide a proximity information, and varying a detection instruction of information of a variable message traffic sign in response to the proximity information to detect a variable message traffic sign.