Driver Assistance Camera Calibration Using Wheel Markers
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Solution Overview
Problem
The calibration of driver assistance system cameras in vehicles is complex due to difficulties in determining their precise position and orientation relative to the vehicle geometry, which is essential for delivering accurate environmental images.
Innovation Solution
A method and device that utilize measurement targets attached to the vehicle's wheels and a calibration target to determine the geometric travel axis and position, allowing for precise calculation of the camera's position and orientation using multiple camera recordings across various vehicle positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional calibration methods are used to determine camera position and orientation, then measurement precision can be achieved, but the calibration process becomes very complex and time-consuming
Solution Approach 1:
The patent introduces a calibration target with specific markers as an intermediary object between the camera and the vehicle. This calibration target serves as a mediator that simplifies the calibration process by providing easily detectable reference points. The markers on the calibration target allow the system to determine camera position and orientation through straightforward geometric calculations rather than complex direct measurements, thus reducing calibration complexity while maintaining precision.
Solution Approach 2:
The patent uses measurement targets attached to the wheels that create measurable geometric patterns. By capturing images of these targets at different vehicle positions and using the known geometry of the targets to calculate camera parameters, the system creates a simplified model for calibration. This copying approach replaces complex direct measurement with easier image-based geometric reconstruction.
2Measurement precision
If traditional calibration methods are used, then accurate camera alignment can be achieved, but the calibration time is significantly increased
Solution Approach 1:
The patent attaches measurement targets to the wheels before the calibration process begins. These pre-positioned targets with known geometries serve as ready-made reference objects. During calibration, the system only needs to capture images of these pre-prepared targets and perform geometric calculations, eliminating the need for complex real-time measurement setups and significantly reducing calibration time while maintaining accuracy.
3Productivity
If simple measurement methods are used, then calibration time is reduced, but measurement precision and reliability deteriorate
Solution Approach 1:
The patent changes the measurement parameters by using known geometric relationships of the calibration target and measurement targets. Instead of complex direct measurements, the system uses the predetermined dimensions and positions of the calibration target markers to simplify calculations. This parameter change enables fast computation while maintaining high precision through the use of accurate geometric models.
Solution Approach 2:
The patent replaces complex mechanical measurement systems with an optical/image-based system. By using cameras to capture images of the calibration target and measurement targets, and then performing geometric calculations on these images, the system achieves both high precision and fast calibration. This substitution of mechanical measurement with optical measurement and computational geometry enables rapid yet accurate camera calibration.
Data Source
Figure 1
AI summary
A method according to the invention for determining the position and orientation of a driver assistance system (DAS) camera of a vehicle relative to the vehicle comprises the following steps: capturing at least one marker (MW) of a measuring target (W) attached to the left wheel of the rear axle and at least one marker of a measuring target attached to the opposite right wheel of the rear axle by two measuring cameras (K1, K2) in at least two vehicle positions; determining the geometric driving axis of the vehicle with respect to the two measuring cameras (K1, K2) therefrom; capturing a driver assistance system calibration target (T1, T2) with the two measuring cameras (K1, K2); determining the position of the driver assistance system calibration target (T1, T2) relative to the two measuring cameras (K1, K2) therefrom; determining the position and orientation of the driver assistance system calibration target (T1, T2) with respect to the geometric driving axis of the vehicle;Acquisition of the driver assistance system calibration target (T1, T2) by the driver assistance system camera (KFAS); determination of the position of the driver assistance system camera (KFAS) relative to the driver assistance system calibration target (T1, T2) from this; and determination of the position and orientation of the driver assistance system camera (KFAS) with respect to the geometric driving axis of the vehicle.