Stop Line Estimation Using Traffic Signal Position Cues
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Solution Overview
Problem
Existing vehicle control systems face challenges in accurately estimating the position of a stop line on a road surface, especially when the stop line is obscured by a preceding vehicle or hidden from the camera's view, leading to potential errors in vehicle control such as deceleration and stopping.
Innovation Solution
A stop line position estimation device that utilizes a traffic signal recognition unit to identify traffic signals at an intersection and estimates the stop line position based on the proximity to these signals, using different distances to differentiate between immediate and rear traffic signals, and considers the presence of hidden traffic signals to improve accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If image recognition by camera is used to detect stop line, then direct stop line position detection is achieved, but detection fails when stop line is rubbed or hidden by preceding vehicle
Solution Approach 1:
The patent introduces traffic signals as intermediary reference objects to indirectly determine stop line position. When the stop line cannot be directly detected (rubbed or hidden), the system uses the detected traffic signal position combined with pre-stored distance information to calculate and estimate the stop line position, thus maintaining detection reliability under obscured conditions.
2Reliability
If traffic signal position is used to estimate stop line position, then estimation is possible when stop line is hidden, but wrong estimation may occur if incorrect traffic signal is selected as reference
Solution Approach 1:
The system employs feedback mechanisms to verify and select the correct traffic signal as reference. By detecting multiple traffic signals and comparing their positions with pre-stored intersection information, the system feedbacks and confirms the appropriate reference signal, preventing wrong estimation caused by selecting incorrect traffic signals.
Solution Approach 2:
The patent detects multiple traffic signals (excessive detection) rather than relying on a single signal. This partial detection approach allows the system to have multiple reference options and select the most appropriate one, improving estimation accuracy while maintaining reliability under various obscured conditions.
3Reliability
If a fixed long distance is used from traffic signal to estimate stop line position, then wrong estimation inside intersection is avoided, but estimation precision deteriorates when traffic signal is in immediate front
Solution Approach 1:
The system applies different distance values based on the local situation - using a first distance when the traffic signal is at the immediate front of the intersection and a second (longer) distance when the traffic signal is at the rear. This local quality approach optimizes estimation precision for each specific scenario while maintaining overall reliability.
Data Source
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AI summary
A stop line position estimation device (101; 201) includes a traffic signal recognition unit (11) configured to recognize a traffic signal at an intersection ahead of a vehicle (M) and a stop line position estimation unit (12; 22) configured to estimate that a position of the stop line is a position from the traffic signal by a first distance toward the vehicle (M) side. When the traffic signal recognition unit (11) recognizes a plurality of traffic signals and the stop line position estimation unit (12; 22) recognizes an immediate front traffic signal and a rear traffic signal based on a positional relationship between the traffic signals, the stop line position estimation unit (12; 22) estimates that the position of the stop line is a position from the immediate front traffic signal by a second distance toward the vehicle (M) side. The second distance is shorter than the first distance.