Single Camera 3D Intra-oral Modeling with Structured Illumination
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Solution Overview
Problem
Current three-dimensional modeling techniques for intra-oral scenes in dental applications face challenges such as limited space, movement issues, and inadequate surface detail, leading to inaccurate and time-consuming measurements.
Innovation Solution
A method using a single camera to capture a two-dimensional image of an intra-oral scene with structured illumination, where random patterns are projected and matched across images to calculate three-dimensional positions, allowing for compact apparatus and reduced movement effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple cameras and complex structured illumination systems are used to achieve accurate 3D modeling, then measurement precision is improved, but device complexity increases and space requirements exceed intra-oral constraints
Solution Approach 1:
The patent divides the complex illumination task into multiple sequential projections of simplified patterns (e.g., alternating light/dark stripe patterns) rather than using a complex single-step illumination system. This segmentation allows accurate 3D modeling to be achieved through multiple simple, sequential imaging operations instead of one complex simultaneous operation
Solution Approach 2:
The patent adds the time dimension to the imaging process by capturing multiple images in sequence with different illumination patterns. This temporal dimension allows a single camera to gather information that would traditionally require multiple cameras simultaneously, resolving the contradiction between measurement precision and device complexity
2Measurement precision
If multiple images are captured to improve 3D modeling accuracy, then measurement precision is improved, but time consumption increases due to patient and practitioner movement
Solution Approach 1:
The patent uses periodic projection of alternating illumination patterns (e.g., light stripes followed by dark stripes) to encode depth information in a time-efficient manner. By periodically switching between patterns and capturing images at specific phases, the system achieves accurate 3D modeling with minimal capture time, reducing the impact of movement during imaging
3Device complexity
If a single camera is used to reduce device complexity and space requirements, then device complexity is reduced, but measurement precision deteriorates due to limited viewing angles
Solution Approach 1:
The patent performs preliminary encoding of depth information by projecting structured illumination patterns before capturing the image. The illumination patterns pre-mark the scene with depth-coded light distributions, allowing a single camera to extract 3D information that would normally require multiple viewing angles. This preliminary action compensates for the single-camera limitation
Solution Approach 2:
The structured illumination patterns serve as an intermediary that carries depth information from the object to the single camera. Instead of relying on the camera's geometric position to provide depth information, the illumination patterns act as a mediator that encodes and transports depth data through the optical path, enabling a single camera to achieve multi-view equivalent precision
4Difficulty of detecting and measuring
If traditional multi-camera systems are used to capture intra-oral scenes, then surface detail detection is improved, but ease of operation deteriorates due to space limitations in the mouth
Solution Approach 1:
The patent extracts the depth-measurement function from the geometric configuration of multiple cameras and transfers it to the structured illumination system. By taking out the depth encoding capability from the camera array and embedding it in the illumination patterns, the system achieves surface detail detection with a single camera, greatly improving ease of operation in the constrained intra-oral environment
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 three-dimensional modeling of intra-oral features with minimal apparatus, reducing the impact of patient and practitioner movement and handling limitations, while accommodating partial views with limited surface detail.
Implementation Method 1
The intra-oral scene is illuminated, during the acquiring of the image by the camera, by a two-dimensional image of structured illumination projected from a first angle with respect to the intra-oral scene
Implementation Method 2
The 'z' information in the intra-oral scene is then recovered from the camera image of the scene under the structured illumination by performing a triangulation of each of the patterns in the array on the single image with reference to an image of the structured illumination projected on a reference plane
Data Source
AI summary
A method for creating three-dimensional models of intra-oral scenes features. The intra-oral scene is illuminated by a two-dimensional array of structured illumination points, with anti-aliasing achieved by using stored two-dimensional patterns of pixels for anti-aliasing. Using a single camera to form images reduces the amount of apparatus necessary to introduce into the patient's mouth. Three-dimensional models are obtained from the single image by triangulation with a stored image of the structured illumination onto a reference surface such as a plane. Alternative methods include the use of “bar-coded” one-dimensional patterns.