Calibration Pattern Projection for Large Measurement Objects
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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 flat surface using a light projector, which allows for relative movement between the projector and the surface, utilizing a beam splitter to generate shifted patterns for material measurement, and incorporating a computer device for triangulation and error correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a large calibration target is used to cover the entire measurement range, then calibration accuracy is improved, but the target becomes difficult to manufacture, handle, and becomes very expensive
Solution Approach 1:
The calibration process is divided into multiple smaller calibration areas instead of using one large calibration target. The system projects calibration patterns onto different sections of the measurement range sequentially, allowing each calibration area to be small and easy to manufacture while collectively covering the entire large measurement space
Solution Approach 2:
A camera is introduced as an intermediary device to capture images of the calibration patterns projected onto the measurement object. The camera enables indirect measurement of calibration patterns, allowing the system to achieve large-area calibration without requiring a physically large calibration target
2Area of stationary object
If multiple calibration positions are used to cover the entire measurement area, then calibration coverage is improved, but calibration time and labor requirements increase significantly
Solution Approach 1:
The system uses dynamic projection of calibration patterns onto the measurement object from different positions and angles. Instead of physically moving large calibration targets between positions, the system projects patterns onto the object at various locations and captures images with the camera, enabling flexible coverage of the entire measurement area without manual repositioning of heavy equipment
Solution Approach 2:
The calibration patterns are projected as optical copies onto the measurement object surface. Multiple calibration areas are accessed by projecting identical or varied patterns onto different locations and capturing them with the camera, eliminating the need to physically transport large calibration targets between positions
3Reliability
If the calibration target is made robust to achieve required stability and dimensional accuracy, then measurement reliability is improved, but the target becomes correspondingly heavy
Solution Approach 1:
The system replaces the mechanical calibration target with an optical projection system. Instead of using a physical rigid target that must be heavy to maintain stability, the system projects calibration patterns using optical means and captures them with a camera, eliminating the need for heavy mechanical structures while maintaining calibration reliability through optical stability
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 calibration by eliminating the need for rigid targets, reduces calibration time, and maintains accuracy by accounting for surface flatness deviations and environmental changes, providing a cost-effective and efficient calibration process for large measurement objects.
Implementation Method 1
various calibration patterns are projected into the detection range of the measuring instrument onto a flat wall or flat surface by means of a light projector
Implementation Method 2
At least two calibration patterns which are laterally spatially displaced relative to one another by a beam offset that provides a standard are generated by means of a polarizer or a beam splitter
Implementation Method 3
An angular error between the mutually displaced parts can be taken into account during calibration by means of triangulation using a computer device
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 an even wall or an even surface by means of a light projector.