Stereo Camera Calibration Device for Wheel Alignment
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Solution Overview
Problem
Existing methods for calibrating stereo camera systems in wheel alignment are complex and require manufacturer-level expertise, making on-site calibration difficult and time-consuming, and accuracy checks cumbersome.
Innovation Solution
A method and device for calibrating stereo camera systems that allows for easy on-site calibration in a workshop setting, using a calibration device with reference features and positioning technology to determine 3D coordinates and orientation parameters, enabling relative and absolute camera calibration, and allowing for camera exchange and maintenance, with a simple structure that does not require additional process steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complex calibration methods with multiple measuring devices are used, then measurement precision is improved, but device complexity and ease of operation deteriorate
Solution Approach 1:
The calibration device is segmented into multiple independent plates (first plate with first reference features, second plate with second reference features, etc.), each plate serving as an independent calibration element. This segmentation allows the complex calibration task to be distributed across multiple simple, manageable components rather than requiring a single complex calibration system.
Solution Approach 2:
The reference features on the calibration plates serve as intermediaries between the measuring cameras and the objects to be measured. The cameras capture images of these known reference features, and the evaluation unit uses them to calculate calibration parameters, thereby mediating the calibration process between the measurement system and the physical world.
2Measurement precision
If manufacturer-level expertise is required for calibration, then measurement precision is improved, but ease of operation and productivity deteriorate
Solution Approach 1:
The calibration system is designed to be self-calibrating through automated image capture and evaluation. The measuring cameras automatically capture images of the calibration plates, and the evaluation unit automatically processes these images to determine calibration parameters, eliminating the need for manual intervention by expert personnel.
Solution Approach 2:
The system transforms the calibration process from a manual, expertise-dependent procedure into an automated parameter-based process. By changing from manual adjustment to automated image processing and parameter calculation, the system makes calibration accessible to non-specialists while maintaining precision.
3Measurement precision
If multiple calibration steps and process steps are required, then measurement precision is improved, but loss of time and productivity deteriorate
Solution Approach 1:
The calibration process merges multiple steps into a single integrated workflow: the evaluation unit simultaneously captures images from multiple cameras, processes all reference features from multiple plates, and calculates all necessary calibration parameters in one operation, eliminating the need for sequential calibration steps.
Solution Approach 2:
The calibration plates are pre-configured with known reference features at predetermined positions before the calibration process begins. This preliminary preparation of calibration data allows the system to perform rapid automated calibration without requiring time-consuming manual setup or measurement during the actual calibration execution.
4Reliability
If stereo camera systems require calibration at manufacturer level, then reliability is improved, but ease of repair and adaptability deteriorate
Solution Approach 1:
The calibration capability is extracted from the manufacturer's controlled environment and brought to the on-site location through a portable calibration device. The calibration plates can be transported to the measurement location, allowing calibration to be performed anywhere without requiring manufacturer-level facilities or expertise.
Solution Approach 2:
The calibration device is designed as a universal solution that can calibrate any stereo camera system used in wheel alignment measurements. The multiple plates with reference features can be used with different camera configurations and positions, making the calibration system adaptable to various installation scenarios while maintaining reliability.
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
Facilitates quick and easy calibration of wheel alignment systems, enabling accurate on-site checks and maintenance, reducing the need for manufacturer involvement and streamlining the calibration process, ensuring high accuracy and ease of use even for non-specialists.
Implementation Method 1
The 3D coordinates of the reference features are determined by at least one recording camera (9) connected to the evaluation unit (13)
Data Source
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AI summary
The invention relates to a method for calibrating a measurement system having at least one image recording apparatus (12) having at least two measurement cameras (31, 32) that form a stereo camera system, and having an analysis unit (13), wherein the measurement system is calibrated by means of a calibration device (22) having reference features (29). The process flow of the method is divided into three steps, wherein in a first step the 3D coordinates of the reference features (29) are determined in a measurement space (30) of the calibration device (22) by at least one image recording camera (9), and in a second step at least one of the image recording apparatuses (12) is disposed in the measurement space (30) of the calibration device (22), and in a third step the 3D coordinates of the at least one image recording apparatus (12) and/or of the at least two measurement cameras (31, 32) are determined in a common 3D coordinate system by means of the analysis unit (13) using the 3D coordinates determined in the first step. The calibration device (22) comprises a measurement space (30) for receiving the image recording apparatus (12) and said measurement space is at least partially bounded by a measurement frame (22) having the reference features (29).