Vehicle Headlight Online Calibration via Projected Light Patterns
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Solution Overview
Problem
Existing methods for calibrating vehicle headlight systems during operation are prone to errors due to changes in geometry and production tolerances, leading to inaccurate distance calculations and ineffective 3D sensor systems.
Innovation Solution
A method involving the projection of a pattern onto a surface, image acquisition, and calculation of specific features to determine the incorrect position of the headlight using geometric correspondence relationships, allowing for online calibration without relying on CAD data or fixed segment widths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If initial calibration is performed during vehicle manufacture with fixed geometry, then calibration is completed once, but subsequent changes in headlight alignment due to adjusting screws or mounting position changes lead to incorrect calibration results
Solution Approach 1:
The patent implements dynamic online calibration that can be performed during vehicle operation rather than relying on static initial calibration. The calibration process is made adaptable to changes in headlight alignment by continuously updating calibration data based on current geometric relationships between the headlight, sensor unit, and projection surface, thereby maintaining accuracy despite mechanical adjustments or mounting position variations.
Solution Approach 2:
The system uses feedback from the sensor unit to detect the actual position of projected light patterns and compares this with expected positions based on initial calibration. This feedback loop enables the system to identify calibration deviations caused by headlight alignment changes and triggers recalibration to correct these errors, ensuring continuous accuracy.
2Adaptability or versatility
If dynamic calibration is performed using active triangulation with characteristic points in light patterns, then online calibration is enabled, but the method requires CAD data and assumes constant segment width which may be impacted by production tolerances
Solution Approach 1:
The patent changes the calibration approach from relying on fixed manufacturing parameters (CAD data, constant segment width) to using dynamically measured geometric relationships. By determining calibration data based on actual positions of characteristic points in projected light patterns and their corresponding image points in the sensor unit, the system adapts to production tolerances and mounting variations without requiring precise manufacturing specifications.
Solution Approach 2:
Instead of relying on theoretical CAD models, the system creates an actual geometric copy of the headlight-sensor relationship through projection and detection. The projected light pattern serves as a physical replica of the headlight's emission characteristics, allowing calibration based on real-world geometry rather than manufactured specifications, thereby accommodating production tolerances.
3Measurement precision
If characteristic points are used for calibration, then trajectory offsets can be determined, but blind incorrect positions of the headlight may exist that do not bring about any offset of the two trajectories
Solution Approach 1:
The patent moves from one-dimensional trajectory offset measurement to two-dimensional spatial relationship analysis by projecting light patterns onto a surface and detecting their positions in the sensor unit's image plane. This dimensional expansion provides additional geometric information that eliminates blind spots where trajectory offsets would be zero, as the projected pattern's position and orientation contain redundant information about headlight alignment in multiple degrees of freedom.
Solution Approach 2:
The projected light pattern serves multiple calibration functions simultaneously: it provides reference points for position measurement, defines trajectories for motion analysis, and creates geometric constraints that eliminate ambiguous calibration states. This multi-functionality ensures that no blind incorrect positions exist, as the pattern's characteristics constrain the solution space to a unique correct calibration state.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables reliable online calibration of headlight systems, correcting initial calibration values and ensuring accurate distance measurements, even in dynamic driving scenarios, by determining the incorrect position of the headlight and adjusting its alignment.
Implementation Method 1
electromagnetic radiation-emitting device configured to emit electromagnetic radiation
Implementation Method 2
sensor unit that is installed in the vehicle... sensor configured to detect electromagnetic radiation emitted by the electromagnetic radiation-emitting device
Data Source
AI summary
A method for calibrating an electromagnetic radiation-emitting device configured to emit electromagnetic radiation using a sensor configured to detect electromagnetic radiation emitted by the electromagnetic radiation-emitting device includes projecting a pattern onto a projection surface by way of the emitted electromagnetic radiation, acquiring an image of the projection of the pattern using the sensor, and calculating at least one trajectory in an image plane of the sensor that describes a propagation of the emitted electromagnetic radiation based on a position of a characteristic feature of the pattern in the image and on a further item of information. The method further includes calculating a specific feature along an associated trajectory and calculating an incorrect position of the device by evaluating a geometric correspondence relationship between points in a world coordinate system and their image points in the image plane of the sensor.