Vehicle Vision System Real-Time Camera Calibration
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Solution Overview
Problem
Conventional vehicle-mounted camera calibration is time-consuming, costly, and prone to changes due to external factors, and existing methods like optical flow determination are impractical for motor vehicles due to limited processing capabilities.
Innovation Solution
The system determines the convergence point of straight lines in images, such as road edges or lane markings, using edge detection algorithms, which requires less processing resources and allows for real-time calibration, and incorporates a confirmation mechanism using vehicle kinematics and image quality to ensure reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical flow determination is used to calculate vanishing point, then vanishing point can be determined, but processing complexity and resource requirements become too high for motor vehicles
Solution Approach 1:
The patent extracts only the essential information needed for vanishing point determination by directly detecting straight lines in images, rather than performing comprehensive optical flow analysis. This extraction approach obtains the necessary vanishing point data while eliminating unnecessary processing complexity, making the system feasible for motor vehicle applications with limited processing resources.
2Measurement precision
If manufacturer calibration is performed, then camera orientation is calibrated, but the process is time-consuming, costly and may still change due to external factors
Solution Approach 1:
The system performs self-calibration by automatically determining the vanishing point from images captured during vehicle operation and using this information to correct lens distortion and orientation. This self-service approach eliminates the need for time-consuming manufacturer calibration while maintaining accurate camera orientation, as the system continuously adapts to external factors like vehicle load and thermal effects.
3Productivity
If convergence point determination is used for real-time calibration, then calibration can be performed during vehicle movement, but reliability may be insufficient under certain conditions
Solution Approach 1:
The system incorporates a confirmation mechanism that uses vehicle kinematics data (acceleration, steering angle, yaw rate) to evaluate the reliability of convergence point determination. When reliability is confirmed, the system applies real-time calibration; when reliability is insufficient, it excludes the convergence point from calibration. This feedback loop maintains both real-time calibration capability and reliability under varying driving conditions.
Data Source
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AI summary
A vision system (10) for a motor vehicle comprises at least one imaging device (12a, 12b) adapted to record images from a region surrounding the motor vehicle, and an electronic processing means (14) for processing said recorded images. The vision system comprises a determination means (30) adapted to determine during driving, by using image processing performed in said processing means (14), at least two essentially straight lines (42a, 42b) in the recorded image (40), to determine a convergence point (46) from said lines, and to determine a current orientation of said imaging device (12a, 12b) based on a position of said convergence point (46).