Virtual Plane Calibration for Large-Scale Measuring Apparatus
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Solution Overview
Problem
Calibrating large measurement objects with existing systems is cumbersome due to the need for large, expensive, and heavy calibration targets, which are difficult to manufacture and handle, and requires extensive time and labor, while environmental changes during calibration can affect accuracy.
Innovation Solution
Projecting calibration patterns onto a mathematically calculated ideally flat surface using a light projector, allowing for relative movement of the calibration projector and measurement setup, and utilizing a polarizer or beam splitter to generate laterally shifted calibration patterns for material measurement, enabling efficient calibration without a rigid target.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If large calibration targets are used to cover the entire measurement area, then measurement precision is improved, but device complexity, manufacturing cost, and handling difficulty increase significantly
Solution Approach 1:
The calibration process is divided into multiple smaller measurement areas. Instead of using one large calibration target covering the entire measurement range, the system uses a small calibration target that is moved to different positions (e.g., nine positions for one level) to cover the complete measurement area incrementally
Solution Approach 2:
A camera is introduced as an intermediary device to photograph the calibration target at different positions. The calibration data from multiple positions are then combined through image processing and coordinate transformation to achieve calibration across the entire large measurement area, avoiding the need for a single large calibration target
2Device complexity
If smaller calibration targets are used to simplify manufacturing and handling, then device complexity is reduced, but calibration time and labor increase due to multiple positions required
Solution Approach 1:
The system pre-calculates and stores calibration data from multiple positions. During actual calibration, the camera photographs the calibration target at different positions, and the system automatically retrieves and combines the pre-calculated calibration data, significantly reducing the time required compared to real-time calculations
Solution Approach 2:
The manual process of moving and repositioning calibration targets is replaced by an automated camera system that photographs the calibration target at predetermined positions. The image processing and coordinate transformation are performed automatically by computer algorithms, reducing manual labor and calibration time
3Measurement precision
If calibration is performed over extended periods to cover multiple planes and angles, then measurement precision is improved, but environmental stability deteriorates due to temperature and lighting changes
Solution Approach 1:
The system pre-calculates and stores calibration data for all required positions and angles. During actual calibration, it quickly captures images at these predetermined positions and combines the pre-calculated data, completing the calibration process rapidly to minimize exposure to environmental changes such as temperature fluctuations and lighting variations
Solution Approach 2:
The calibration process is designed to be completed continuously in one session rather than being divided into multiple separate calibration events. By rapidly capturing all necessary images and processing them together, the system maintains consistent environmental conditions throughout the calibration process
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 method simplifies and accelerates calibration, reduces errors caused by surface flatness deviations, and maintains accuracy by using a virtual plane for calibration, allowing for effective measurement of large objects with minimal equipment and handling challenges.
Implementation Method 1
a light projector (P) projecting different calibration patterns (M1, M2, Ni) into the detection area (S) of the measuring device (M) on a real flat wall (W) or real flat surface (S) can be projected
Implementation Method 2
At least one calibration pattern (M1, M2) which is laterally spatially shifted relative to the other calibration pattern with a beam offset (S) that provides a material measure can be generated by means of a polarizer or a beam splitter (T)
Data Source
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AI summary
The invention relates to a device and a method for calibrating a measuring apparatus for measuring a measurement object that extends especially over several meters in space, comprising a detection zone covering the entire measurement object. According to said method, various calibration patterns (Mi) are projected into the detection zone of the measuring apparatus onto a real even wall or a real even surface by means of a light projector. The real even wall or real even surface is mathematically calculated as the ideal even wall or ideal even surface by means of a computing device and the result of calculation is used for calibration.