Vehicle Distance Measurement via Trajectory-Based Triangulation
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Solution Overview
Problem
Existing distance measurement systems in motor vehicles face challenges due to image processing and calibration errors, which can result in the non-existence of the point of intersection of rays, necessitating resource-intensive and complex triangulation algorithms to provide continuous, online-capable distance data.
Innovation Solution
A method that determines three-dimensional ray paths and transforms them into two-dimensional trajectories within the vehicle's image, correlating points on the ray paths with points on the trajectories to calculate distances between the vehicle and a projection surface, eliminating the need for resource-consuming triangulation algorithms by integrating distance determination into the calibration and image processing steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional triangulation algorithms are used to calculate distance from ray intersection points, then distance measurement can be performed, but the method requires resource-intensive complex calculations and may fail when intersection points do not exist due to image processing and calibration errors
Solution Approach 1:
The patent pre-calculates and stores correspondence relationships between image coordinates and three-dimensional space coordinates during a calibration phase. This preliminary action creates lookup tables and transformation matrices that enable direct distance calculation during runtime without executing complex triangulation algorithms, thereby reducing computational complexity while maintaining measurement precision
Solution Approach 2:
The patent creates a pre-computed model (copy) of the geometric relationship between the camera and headlight units during calibration. This model includes pre-calculated ray paths and correspondence points that are stored and reused during distance measurement, eliminating the need to perform complex geometric calculations in real-time
2Measurement precision
If complex triangulation algorithms are implemented to ensure accurate distance measurement, then measurement precision is improved, but the computational resources and processing time increase, making it difficult to operate continuously online
Solution Approach 1:
By performing calibration and pre-computing correspondence relationships before actual distance measurement, the patent shifts computational burden to an offline phase. During online operation, only simple lookups and basic calculations are required, enabling continuous distance measurement at high speed without resource exhaustion
Solution Approach 2:
The patent transforms the problem from three-dimensional ray intersection calculations to two-dimensional image coordinate transformations. By working in the image plane and using pre-computed correspondence relationships, the method reduces computational dimensions and complexity while maintaining measurement accuracy
3Measurement precision
If the point of intersection of rays is calculated to determine distance, then distance measurement is possible, but the point of intersection frequently does not exist due to image processing and calibration errors
Solution Approach 1:
The patent introduces an intermediary calibration model that maps image coordinates to three-dimensional space coordinates through pre-determined correspondence relationships. This intermediary approach avoids direct ray intersection calculations that are sensitive to errors, instead using a robust lookup-based method that tolerates calibration inaccuracies
Solution Approach 2:
The patent changes the calculation parameters from requiring precise ray intersection points to using correspondence relationships defined during calibration. By transforming the problem from geometric intersection to coordinate transformation with pre-stored parameters, the method becomes more tolerant of image processing and calibration variations
Data Source
AI summary
A method for ascertaining a distance between a vehicle and a projection surface, onto which a characteristic light pattern is projected using a headlight of the vehicle, includes detecting, in an image of the characteristic light pattern captured by an image capturing unit, a characteristic structure produced by a first light-producing unit by evaluating a geometric location relationship in the captured image between the trajectory and characteristic structures of a characteristic light pattern that are located in an environment along the trajectory; calculating a point on the ray path that is correlated with a position of the detected characteristic structure on the trajectory in accordance with the transformation rule; and calculating the distance between the vehicle and the projection surface from the calculated point on the ray path.