Laser Line Scanner Tracking With Projected Workpiece Markers
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Solution Overview
Problem
Existing coordinate measuring systems using laser line scanners face measurement errors due to inaccuracies in determining the position and orientation of the scanning module, especially at large working distances, which can lead to incorrect geometry determination of workpieces, particularly when using optical markers for tracking.
Innovation Solution
A coordinate measuring system that includes a laser line scanner and a projection device to project optical markers onto a workpiece surface, allowing for precise determination of the scanning module's position and orientation by capturing image data from an optical sensor, thereby minimizing measurement inaccuracies and decoupling the markers from the scanning module, making the system working distance-independent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical markers are used for tracking the scanning module position and orientation, then the coordinate measuring system can determine the scanning module's location in the external coordinate system, but measurement errors increase at large working distances due to inaccuracies in determining marker position and orientation
Solution Approach 1:
The patent introduces a projection device that projects optical markers directly onto the workpiece surface as an intermediary element. This allows the markers to be tracked by external optical sensors while being spatially related to the scanning module's measurement position, enabling accurate position and orientation determination even at large working distances without the errors that plague direct marker attachment methods
Solution Approach 2:
The patent replaces the mechanical attachment of physical markers to the scanning module with an optical projection system. Instead of mechanically fixing markers to the moving scanning module (which creates alignment and visibility problems), the system uses optical projection to create virtual markers on the workpiece surface, eliminating mechanical constraints and improving measurement accuracy at various working distances
2Reliability
If physical optical markers are attached to the scanning module, then tracking is possible, but errors occur due to marker placement inaccuracies and visibility issues
Solution Approach 1:
The projection device acts as an intermediary between the scanning module and the external optical sensors, creating virtual optical markers on the workpiece surface without requiring physical attachment. This eliminates placement inaccuracies and visibility issues associated with physical markers while maintaining reliable tracking
Solution Approach 2:
Instead of using physical markers that must be attached and maintained, the system creates optical copies (projected images) of markers on the workpiece surface. These projected markers can be freely positioned and adjusted without physical constraints, eliminating placement errors and simplifying the system
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
The system minimizes measurement inaccuracies and avoids errors associated with marker placement and visibility issues, enabling accurate geometry determination of workpieces even at larger working distances without increasing measurement inaccuracy.
Implementation Method 1
The underlying mathematical-physical principle in this case is generally known as a triangulation principle
Implementation Method 2
the laser radiation of the laser line projected onto the workpiece that has been reflected by the workpiece, for example, is captured
Data Source
AI summary
A coordinate measuring system includes a scanning module having a laser line scanner and a projection device. The laser line scanner projects a laser line onto a surface of a workpiece and produces scan data from a reflection of the laser line. The projection device and/or the laser line scanner project three optical markers onto the surface of the workpiece, at least one of the three markers being disposed on the laser line and at least one of the three markers being at a distance from the laser line. The coordinate measuring system includes an optical sensor capturing image data of the three optical markers and an evaluation device determining a position and an orientation of the coordinate system of the laser line scanner in the coordinate system of the optical sensor based on the image data of the optical sensor and the scan data of the laser line scanner.