Hitch Ball Position Detection via Perpendicular Bisectors
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Solution Overview
Problem
Existing vehicle vision systems struggle to accurately determine the position of a hitch ball when a trailer is connected to a towing vehicle, especially under varying conditions such as different trailer types, road types, and lighting conditions, which can lead to inaccurate trailer angle measurement and increased risk of jack-knife situations or collisions.
Innovation Solution
A camera-based system that processes image data to detect the hitch ball position by performing feature matching between frames, calculating perpendicular bisectors, and determining their intersection point, which represents the center of rotation of the trailer, thereby accurately locating the hitch ball.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a camera-based vision system is used to detect hitch ball position, then the system can handle various trailer types and lighting conditions, but the measurement precision of hitch ball position deteriorates due to image processing complexity and feature matching variability
Solution Approach 1:
The system uses perpendicular bisectors as an intermediary geometric construct to indirectly determine the hitch ball position. Instead of directly detecting the hitch ball, the system detects feature points on the trailer, calculates perpendicular bisectors of lines connecting these points, and finds their intersection, which serves as a mediator to locate the hitch ball position accurately across varying conditions
Solution Approach 2:
The system transitions from direct 2D image space coordinate detection to a geometric construction approach by introducing perpendicular bisectors (adding a geometric dimension). This dimensional transformation allows the system to achieve more robust position determination that is less sensitive to variations in trailer type and lighting conditions
2Reliability
If feature matching between multiple frames is performed to determine hitch ball position, then the system can improve reliability under varying conditions, but the device complexity increases due to multiple image processing steps
Solution Approach 1:
The image processing task is segmented into distinct sequential steps: feature point detection in multiple frames, matching corresponding features between frames, calculating perpendicular bisectors for each matched pair, and determining the intersection point. This segmentation allows each step to be optimized independently and improves reliability through systematic multi-frame analysis
Solution Approach 2:
The system performs preliminary feature point detection and matching between frames before calculating the final hitch ball position. By pre-identifying and matching feature points across multiple frames, the system establishes a reliable foundation for subsequent perpendicular bisector calculations, improving overall detection reliability while organizing complexity into manageable preliminary and final stages
Data Source
AI summary
A vehicular trailering assist system includes a camera disposed at a rear portion of a vehicle. With a trailer hitched to the vehicle at a hitch ball of the vehicle, the camera views at least a portion of the trailer. An electronic control unit includes an image processor operable to process frames of image data captured by the camera. With the trailer hitched to the vehicle at the hitch ball of the vehicle, the vehicular trailering assist system determines trailer feature points via image processing of image data captured by the camera, and determines respective perpendicular bisectors of respective line segments extending between the determined trailer feature points in respective frames of captured image data while the vehicle tows the trailer and turns. The vehicular trailering assist system determines a location of the hitch ball based at least in part on an intersection point of the determined perpendicular bisectors.