Handheld 3D Scanner Self-Positioning via Target Features
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Solution Overview
Problem
Existing three-dimensional scanning systems require external positioning devices for accurate hand-held operations, which increase complexity, cost, and can be cumbersome, especially when dealing with objects of weak geometry variations or those with symmetries like spherical, cylindrical, or planar shapes, leading to inconsistent positioning quality.
Innovation Solution
A hand-held 3D laser scanning system that simultaneously measures surface geometry and models positioning features in real-time using a single device, embedding a laser pattern projector, objectives, light detectors, and an image processor to calculate 3D surface and positioning features, allowing for self-positioning without relying on the object's surface geometry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If external positioning devices are used for hand-held 3D scanning, then positioning accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The scanner performs self-positioning by detecting positioning features in the scene and calculating its own pose relative to a global coordinate system. The system uses its imaging device to capture positioning features, processes these features to determine spatial transformation parameters, and applies these parameters to transform surface points into the global coordinate system, eliminating the need for external positioning devices.
Solution Approach 2:
Positioning features serve as intermediaries between the scanner and the global coordinate system. These features are detected in the scene, used to calculate spatial transformation parameters, and enable the scanner to determine its position and orientation without requiring direct external positioning equipment attached to or near the scanner.
2Measurement precision
If external positioning devices are used for hand-held 3D scanning, then positioning accuracy is improved, but ease of operation deteriorates
Solution Approach 1:
The scanner autonomously performs positioning by detecting positioning features and calculating its own pose. The processor automatically processes the detected positioning features to compute spatial transformation parameters and transforms surface points into the global coordinate system, making the system self-sufficient and eliminating cumbersome external positioning equipment.
3Device complexity
If positioning relies on object surface geometry, then no additional features are needed, but positioning quality becomes inconsistent for objects with weak geometry variations or symmetries
Solution Approach 1:
Positioning features serve as reliable intermediaries that provide consistent positioning information regardless of the object's surface geometry. These features are detected in the scene and used to calculate spatial transformation parameters, ensuring accurate positioning even for objects with weak geometry variations or symmetries where surface geometry alone would be insufficient.
Solution Approach 2:
The system changes from relying solely on geometric parameters of the object surface to using parameters derived from detected positioning features. By processing these features to obtain spatial transformation parameters, the system achieves consistent positioning quality across different object geometries, including those with symmetries or weak geometry variations.
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 accurate and efficient 3D scanning by continuously calculating its own position and orientation, allowing for the simultaneous building and matching of 3D representations of positioning features while accumulating surface points, thus eliminating the need for external positioning devices and ensuring consistent quality across various object geometries.
Implementation Method 1
a set of at least one laser pattern projector
Implementation Method 2
obtaining at least one set of 2D surface points originating from the reflection of the projected laser pattern on the object's surface
Implementation Method 3
a 3D surface point calculator for transforming the said sets of 2D surface points into a set of 3D surface points
Data Source
AI summary
A system, apparatus and method for three-dimensional scanning and digitization of the surface geometry of objects are claimed. The system includes a hand-held apparatus that is auto-referenced. The system is auto-referenced since it does not need any positioning device to provide the 6 degree of freedom transformations that are necessary to integrate 3D measurements in a global coordinate system while the apparatus is manipulated to scan the surface. The system continuously calculates its own position and orientation from observation while scanning the surface geometry of an object. To do so, the system exploits a triangulation principle and integrates an apparatus that captures both surface points originating from the reflection of a projected laser pattern on an object's surface and 2D positioning features originating from the observation of target positioning features.