Camera Calibration Device Using Feature Point Trajectories
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Solution Overview
Problem
Existing camera calibration methods require a white line on the road to calibrate internal parameters, which is not feasible in all scenarios, leading to errors in distance calculations due to lens distortion changes caused by temperature and heat expansion.
Innovation Solution
A camera calibration device that extracts and tracks feature points from images captured by a vehicle-mounted camera, estimates trajectories based on vehicle movement, and calculates internal parameters, including lens distortion coefficients, using polynomial approximation and correspondence determination to minimize trajectory differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a white line on the road is used for calibration, then internal parameters can be estimated, but calibration cannot be performed without the white line
Solution Approach 1:
The invention extracts the calibration function from the specific context of white line detection and generalizes it to work with any feature points on the road surface. By separating the calibration logic from the white line constraint, the system can now use diverse road features (markings, edges, objects) for calibration, thereby improving adaptability while maintaining measurement precision
Solution Approach 2:
The calibration device is designed to handle multiple types of road features universally. Instead of being specialized for white lines only, the system can process various feature points including road markings, curbs, and other road surface elements, making the calibration function versatile and applicable in diverse driving scenarios
2Productivity
If internal parameters are derived in advance, then production efficiency is improved, but lens distortion changes due to temperature and heat expansion cause errors in distance calculation
Solution Approach 1:
The system transitions from static pre-derived internal parameters to dynamic calibration that adapts to changing conditions. By performing calibration during vehicle movement using real-time feature point tracking, the system adjusts internal parameters to account for thermal expansion and distortion changes, maintaining distance calculation accuracy while preserving production efficiency through automated calibration
Solution Approach 2:
The calibration system uses feedback from tracked feature point trajectories to continuously refine internal parameters. By comparing expected trajectories with actual observed trajectories and adjusting parameters accordingly, the system compensates for distortion changes caused by temperature variations, ensuring accurate distance calculations despite environmental conditions
Data Source
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AI summary
This camera calibration device is provided with: an image acquisition unit into which a plurality of images captured at different times by a camera mounted to a vehicle are inputted; a feature point extraction unit which extracts features points from each of the images inputted into the image acquisition unit; a feature point tracking unit which tracks the feature points between the plurality of images; a vehicle movement acquisition unit which acquires information related to the movement of the vehicle; a trajectory estimation unit which, on the basis of the information acquired by the vehicle movement acquisition unit, estimates the trajectory of the feature points corresponding to the movement of the vehicle; and an internal parameter estimation unit which estimates internal parameters of the camera on the basis of the trajectory of the feature points tracked by the feature point tracking unit, and the trajectory of the feature points estimated by the trajectory estimation unit.