Traffic Light Phase Assistant Camera Field of View Management

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Solution Overview

Problem

Existing vehicle traffic light phase assistant systems face challenges in maintaining the traffic light within the camera's field of view across various traffic situations, leading to potential loss of functionality when the traffic light wanders out of view.

Innovation Solution

A method that determines the length of a route to keep the traffic light in the camera's view by calculating a control signal indicating the necessary stopping point, which is displayed to the driver and can intervene in the vehicle's braking system to ensure the traffic light remains visible, using either a stereo or mono camera for distance estimation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the vehicle stops automatically at detected traffic lights, then the traffic light phase assistant functionality is improved, but the traffic light may wander out of the camera's field of view causing loss of functionality

Engineering Contradiction:
Improvetraffic light phase assistant functionalityVSAvoidcamera field of view management
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system calculates the optimal stopping position in advance by determining the route length that keeps the traffic light in the camera's field of view. The control unit computes this route length based on camera parameters and traffic light position before the vehicle actually stops, allowing preliminary planning of the stopping action to ensure continuous visibility.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system continuously monitors the traffic light's position within the camera's field of view and uses this feedback to adjust the calculated route length. The control unit receives information about the traffic light's current position and modifies the stopping position calculations accordingly, creating a closed-loop control system that adapts to changing conditions.

Inventive Principle:
Principle #23Feedback

2Reliability

If the camera's field of view is restricted upward, then other road elements like lane markings and traffic signs are detected better, but light signals from traffic lights cannot be recorded

Engineering Contradiction:
Improvedetection of road elementsVSAvoidtraffic light detection capability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The system solves the field of view restriction problem by changing the dimensional approach - instead of trying to capture both the upward-directed traffic lights and the forward-facing road elements in a single camera view, it uses the calculated route length as an additional control dimension. This allows the vehicle to stop at a specific distance that ensures the traffic light remains visible while the camera maintains its original upward-restricted orientation for detecting road markings and signs.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Reliability

If the vehicle stops at the stop line, then the traffic light phase assistant works correctly, but the stopping position may be too far in front of the traffic light

Engineering Contradiction:
Improvetraffic light phase assistant operationVSAvoidstopping position accuracy
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The system changes the stopping position parameter from a fixed stop line location to a dynamically calculated route length. Instead of always stopping at the predetermined stop line, the control unit calculates the optimal stopping distance based on the traffic light's current position in the camera's field of view, adjusting the stopping parameter to ensure the traffic light remains visible while avoiding excessive distance from the stop line.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2925581B1Method for assisting a traffic light phase assistant of a vehicle, which detects a traffic light
Publication Date: 2019.02.06 CONTI TEMIC MICROELECTRONIC GMBH
  • EP2925581B1 patent drawingFigure 1~2

AI summary

The invention relates to a method for assisting a traffic light phase assistant of a vehicle (10), which detects the traffic light phases of a traffic light (11) by means of a camera (1). According to the invention there is provision that when a traffic light (11) is detected in the field of vision (1a) of the camera (1) the length (L) of the travel path (W) in the direction of the traffic light (11) which keeps the camera (11) in its field of vision (1a) is determined by means of a control unit (3), and a control signal (St) which relates to the length (L) of the travel path (W) is output.