3D Line Scanner Tracking Modes for Marker-Free Registration
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Solution Overview
Problem
Existing handheld line scanners require adhesive markers for registration and are constrained by electrical wires, and they lack the ability to capture high dynamic range images efficiently.
Innovation Solution
A system comprising a first target-mode projector, a first illuminator, a first geometry-mode projector, and two cameras, along with processors to determine 3D coordinates based on captured images, and a photogrammetry camera with a wearable unit for wireless and wired connections, enabling marker-free registration and high dynamic range imaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If adhesive markers are attached to the object for registration, then measurement accuracy is improved, but the complexity of the measurement process increases and time is lost in marker application and removal
Solution Approach 1:
The patent removes the adhesive markers from the measurement system entirely. Instead of using external markers that need to be attached and removed, the system uses the object's own geometric features (edges, corners, surfaces) as registration targets. The line scanner captures images of these natural features and uses them for automatic registration, eliminating the marker application step while maintaining measurement accuracy.
Solution Approach 2:
The object itself serves as the registration target rather than requiring external markers. The line scanner uses the object's inherent geometric features (edges, corners, surfaces) to establish coordinate systems and register measurements. This self-service approach eliminates the need for separate marker materials and their application/removal processes.
2Measurement precision
If adhesive markers are used for registration, then coordinate registration is achieved, but measurement time increases due to marker application and removal
Solution Approach 1:
The patent extracts the registration function from the adhesive marker system and integrates it directly into the line scanner's imaging and processing system. The scanner automatically identifies geometric features in captured images and performs registration computations, eliminating the time-consuming manual marker application and removal steps while maintaining coordinate registration accuracy.
Solution Approach 2:
The system performs preliminary identification of geometric features during the normal scanning process. As the line scanner captures images of the object, it simultaneously identifies edges, corners, and surfaces, and uses these features for registration. This preliminary action occurs during the measurement itself rather than requiring separate preparation steps, thus eliminating time loss.
3Reliability
If electrical wires connect the handheld scanner to the computer, then data transmission is reliable, but the operator's mobility is constrained
Solution Approach 1:
The patent replaces the mechanical electrical wire connection system with a wireless communication system. The handheld line scanner transmits measurement data to the computer using wireless technologies (such as Wi-Fi or other wireless protocols), eliminating the physical cable constraint while maintaining reliable data transmission. This allows the operator to move freely around the object being measured without being tethered by wires.
4Device complexity
If standard imaging is used in handheld scanners, then device simplicity is maintained, but high dynamic range images cannot be captured efficiently
Solution Approach 1:
The patent segments the imaging process into multiple exposures with different exposure settings. The line scanner captures several images of the same scene at different exposure levels (underexposed, properly exposed, overexposed) and then combines these segments into a single high dynamic range image. This allows the system to capture both very bright and very dark areas of the object surface effectively, maintaining device simplicity while achieving high dynamic range imaging capability.
Solution Approach 2:
The system uses periodic action by capturing multiple images in rapid succession with different exposure settings. The line scanner quickly alternates between different exposure modes and combines the results, creating high dynamic range images efficiently. This periodic capture and combination process maintains simplicity while achieving superior dynamic range performance.
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 marker-free registration and high dynamic range imaging without the need for intermediate computations, allowing for faster and more efficient measurement of large objects.
Implementation Method 1
An LLP or handheld line scanner uses the principle of triangulation to determine 3D coordinates of points on an object relative to the LLP coordinate system (frame of reference)
Implementation Method 2
a first illuminator operable to illuminate markers on or near the object
Data Source
AI summary
A handheld three-dimensional (3D) measuring system operates in a target mode and a geometry mode. In the target mode, a target-mode projector projects a first line of light onto an object, and a first illuminator sends light to markers on or near the object. A first camera captures an image of the first line of light and the illuminated markers. In the geometry mode, a geometry-mode projector projects onto the object a first multiplicity of lines, which are captured by the first camera and a second camera. One or more processors determines 3D coordinates in the target mode and the geometry mode.