Vehicle Headlight Calibration Using Inverse Pattern Image Subtraction
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Solution Overview
Problem
Existing methods for calibrating vehicle headlights face challenges in maintaining safety-relevant accuracy due to misalignment caused by mechanical stresses, thermal expansion, and environmental conditions, particularly vertical misalignment, which can affect visibility and safety, and are exacerbated by high-resolution lighting systems like LCD and µLED technologies.
Innovation Solution
A method involving capturing at least three images, subtracting images with and without a calibration pattern, and using circles with known positions to simplify the evaluation algorithm, allowing robust and accurate calibration of headlights by identifying and correcting misalignments using stepper motors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional alignment methods using alignment booms and multiple technicians are used, then alignment accuracy can be achieved, but the process time is excessive (30-45 minutes per vehicle) and labor costs are high
Solution Approach 1:
The patent replaces the mechanical alignment boom system with an optical/laser-based measurement system. The laser projector projects reference patterns onto the vehicle, and cameras capture images for digital analysis, eliminating the need for physical alignment booms and manual measurement procedures.
Solution Approach 2:
The system creates a digital copy of the alignment reference system by projecting laser patterns that represent the ideal headlight alignment geometry. Instead of using physical alignment tools, the system uses optical copies (laser projections) that can be captured and analyzed digitally, enabling faster and more consistent measurements.
2Reliability
If traditional alignment methods are used, then alignment can be performed, but the complexity of the procedure and training requirements for technicians is excessive
Solution Approach 1:
The system performs self-alignment by automatically capturing images of the laser reference patterns and calculating headlight adjustments without requiring technician interpretation. The automated image processing and calculation algorithms eliminate the need for trained technicians to manually measure and interpret alignment data.
Solution Approach 2:
The patent replaces complex mechanical alignment procedures with automated optical measurement and digital image processing. The system uses software algorithms to automatically analyze captured images and determine alignment adjustments, eliminating the need for technicians to understand complex mechanical alignment procedures.
3Measurement precision
If conventional alignment equipment is used, then alignment can be achieved, but the equipment cost and facility space requirements are excessive
Solution Approach 1:
The system divides the alignment measurement function into separate modular components: a laser projector unit, camera units, and a processing system. This segmentation allows the equipment to be more compact and flexible in deployment compared to traditional integrated alignment booms that require large fixed facilities.
Solution Approach 2:
The patent replaces large mechanical alignment equipment with compact optical devices (laser projectors and cameras). These devices require minimal facility space compared to traditional alignment booms and can be deployed in more flexible locations, reducing both equipment cost and facility requirements.
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
Enables highly accurate and autonomous calibration of vehicle headlights, immune to environmental conditions, ensuring safety and convenience by maintaining precise headlight alignment without additional hardware, and adapting projections to the vehicle's front field.
Implementation Method 1
a camera (144) is positioned to capture an image of the target
Data Source
Figure 1~2
Figure 3
AI summary
The invention relates to a method (1) for calibrating vehicle headlights. An incorrect position of a pre-defined light distribution is determined by evaluating images of at least one vehicle camera. The invention is characterized in that in a first step (2), at least three images are captured, wherein a first image (3) is captured with a calibration pattern (4), a second image (5) is capture without the calibration pattern (4), and a third image (6) is captured with the inverse calibration pattern (4'); and in a second step (7), the second captured image (5) is subtracted from the first and third captured image (3, 6) in order to clean up the captured images (3, 6) of an existing scene.