Trailer Angle Detection Using Vanishing-Point Image Analysis

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Solution Overview

Problem

Current methods for determining the pitch, yaw, and roll angles of a trailer relative to a towing vehicle are restrictive, requiring specific trailer geometries and calibration processes, limiting their applicability, especially when starting the vehicle or for non-standard trailer types.

Innovation Solution

A system comprising a camera mounted on the towing vehicle to acquire images of the trailer with lines parallel to its axis, using line detection algorithms to identify vanishing lines and calculate the pitch, yaw, and roll angles without the need for calibration, by determining the vanishing points and applying trigonometric calculations based on image coordinates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If image analysis methods based on front face detection are used to determine trailer pose, then yaw angle can be determined, but the method is restrictive and does not apply to trailers with non-standard geometries (tanks, wood, horse trailers)

Engineering Contradiction:
Improveapplicability to different trailer typesVSAvoiddetection complexity
Core Design Contradiction:
Adaptability or versatilityVSDifficulty of detecting and measuring

Solution Approach 1:

The invention extracts the essential geometric feature (vanishing point of parallel lines) from the trailer structure, removing the need to detect the entire front face. By focusing only on parallel lines extending from the trailer body, the method becomes applicable to various trailer types while maintaining detection feasibility through standard line detection algorithms

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention changes the detection parameter from front face geometry to vanishing point position. This parameter transformation allows the system to work with any trailer that has parallel structural lines, significantly expanding adaptability while the vanishing point calculation provides a standardized measurement approach

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If calibration phase with straight-line driving is required to determine reference position, then reference values for yaw angle can be established, but implementation conditions are restricted and cannot be implemented when vehicle is started

Engineering Contradiction:
Improvereference position accuracyVSAvoidimplementation conditions
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The invention performs preliminary action by establishing the vanishing point as the reference position directly from the current image, eliminating the need for a separate calibration phase. The vanishing point inherently provides the reference frame needed for angle calculation, allowing immediate operation upon vehicle start

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses the trailer's own structural lines to automatically establish the reference position through vanishing point detection. This self-service approach eliminates external calibration requirements, as the trailer's geometry itself provides the reference information needed for accurate measurement

Inventive Principle:
Principle #25Self-service

3Ease of operation

If vanishing point method is used to determine pitch angle from vertical coordinate, then pitch angle can be calculated without calibration, but the method requires visible lines parallel to trailer axis in the image

Engineering Contradiction:
Improvecalibration requirementVSAvoidimage feature visibility
Core Design Contradiction:
Ease of operationVSDifficulty of detecting and measuring

Solution Approach 1:

The vanishing point detection method serves multiple functions: it provides both the reference position and the pitch angle measurement from the same feature. This multi-functionality eliminates calibration while using standard line detection algorithms that can identify parallel lines in most typical imaging conditions

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP4094225B1System for determining the angular position of a trailer
Publication Date: 2024.02.07 CONTINENTAL AUTONOMOUS MOBILITY GERMANY GMBH
  • EP4094225B1 patent drawingFigure 1~2
  • EP4094225B1 patent drawingFigure 3
  • EP4094225B1 patent drawingFigure 4

AI summary

The invention relates to a system (1) for determining at least one pitch angle of a trailer relative to a tractor (21), the system comprising a camera (12) mounted on the tractor (21) and capable of acquiring images of the trailer in which lines of the trailer parallel to the trailer axis (20) are visible, and a computer (10) configured to perform the following steps: - implementing a line-detection algorithm on at least one image of the trailer acquired by the camera (12), - detecting in the image the lines of the trailer parallel to the trailer axis, corresponding to vanishing lines, and deducing from the vanishing lines a position of the vanishing point, and - from the coordinates of the vanishing point, determining at least one pitch angle of the trailer with respect to the tractor.