Structured Light Photogrammetry for Dental 3D Modeling
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Solution Overview
Problem
Photogrammetry techniques are computationally expensive and difficult to adapt for dental imaging due to the challenge of matching pixels on surfaces with few features, limiting their application in obtaining accurate 3D models of dental items.
Innovation Solution
A structured light pattern digitizing method combined with photogrammetry is used, employing a digitizer with a projection portion and imaging portions to project patterns onto dental items, allowing for the determination of 3D coordinates through triangulation and subsequent photogrammetry computations, which include iterative closest pair alignment and pixel matching algorithms to generate accurate 3D models.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If photogrammetry is used to obtain 3D coordinates, then measurement precision is improved, but computational complexity increases and pixel matching becomes difficult on surfaces with few features
Solution Approach 1:
The patent applies preliminary action by projecting structured light patterns onto the object surface before performing photogrammetry. This pre-establishes known feature points and geometric constraints on the surface, which then guide the pixel matching process. The structured patterns are projected in advance to create artificial features that make subsequent feature detection and matching significantly easier, resolving the contradiction between measurement precision and computational complexity.
2Measurement precision
If photogrammetry is used for dental imaging, then measurement precision is improved, but ease of operation deteriorates due to difficulty in matching pixels on surfaces with few features
Solution Approach 1:
The patent applies local quality by projecting structured light patterns with specific local features (such as grids, lines, or dots) onto specific regions of the dental object surface. These localized patterns create distinct visual markers at specific locations, making it easy to identify and match corresponding points between different views. This resolves the pixel matching difficulty on surfaces with few natural features while maintaining high measurement precision.
3Manufacturing precision
If traditional photogrammetry is used, then 3D model accuracy is improved, but productivity decreases due to computationally expensive algorithms
Solution Approach 1:
The patent applies segmentation by dividing the object surface into multiple regions and projecting different structured light patterns onto each region. This allows the photogrammetry process to focus on matching patterns within smaller, manageable segments rather than processing the entire surface at once. The segmented approach reduces computational complexity and processing time while maintaining overall 3D model accuracy, thus improving productivity without sacrificing precision.
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 approach enables efficient and accurate generation of 3D models of dental items by reducing computational load and improving feature matching, facilitating the creation of precise restoration models for dental applications.
Implementation Method 1
A projection portion projects a pattern onto an object, and one or more imaging portions observe the projected pattern on the object to determine a point cloud of three-dimensional (3D) coordinates on the surface of the object
Data Source
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AI summary
A structured light pattern digitizing method is combined with photogrammetry to determine a 3D model of an object. The structured light digitizing operation generates a 3D model of the object being scanned, and this model is then used to compute a higher accuracy model using photogrammetry.