Mirror-Directed Structured Light for Powder-Free Intraoral Scanning
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Traditional dental impressions using structured light three-dimensional imaging face challenges due to high reflectivity and translucency of teeth, leading to reduced contrast in the structured light pattern, necessitating the use of opaque powders for improved capture, and the correspondence problem between projected and captured light patterns.
Innovation Solution
Employing an intraoral scanning device with multiple miniature cameras and projectors that utilize laser diodes and diffractive/refractive pattern generating optical elements to project non-coded, discrete unconnected spots of light, combined with a correspondence algorithm to triangulate and decode the light patterns, eliminating the need for opaque powders and enhancing image capture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If structured light three-dimensional imaging is used to capture intraoral surfaces, then 3D scanning capability is achieved, but image contrast is reduced due to high reflectivity and translucency of teeth
Solution Approach 1:
The patent changes the parameter of light coding from non-coded to coded patterns. By projecting coded structured light patterns (such as phase-shifted fringe patterns or binary codes) instead of simple uniform illumination, the system can uniquely identify and track light pattern points even on highly reflective and translucent tooth surfaces, thereby maintaining measurement precision without requiring opaque powder coating to improve contrast.
Solution Approach 2:
The patent introduces coded light patterns as an intermediary carrier that encodes spatial information. These coded patterns act as a mediator between the light source and the camera, allowing the system to distinguish reflected light from different surface points even when the teeth surfaces are highly reflective or translucent, thus solving the contrast problem without altering the physical state of the teeth.
2Illumination intensity
If opaque powder is applied to tooth surfaces to improve contrast, then image capture quality is enhanced, but the correspondence problem between projected and captured light patterns becomes more difficult to solve
Solution Approach 1:
Instead of applying opaque powder to improve contrast and then dealing with the correspondence problem, the patent inverts the approach by using coded light patterns that inherently encode positional information. This allows the system to solve the correspondence problem through decoding the coded patterns rather than through complex image matching algorithms, thereby reducing overall system complexity while maintaining high contrast capability.
3Quantity of substance
If conventional structured light patterns are projected, then light pattern projection is achieved, but heating and costs increase
Solution Approach 1:
The patent employs periodic action by using pulsed or intermittent projection of structured light patterns instead of continuous illumination. By projecting coded patterns in periodic sequences (such as multiple phase-shifted patterns in succession), the system achieves the necessary measurement data while reducing the total energy input and associated heating effects, thereby lowering energy loss and operational costs.
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 improves image capture accuracy and reduces heating, costs, and complexity by maintaining high contrast and resolution while avoiding the need for contrast enhancement, thus enhancing the precision of dental scans.
Implementation Method 1
intraoral scanners often use structured light three-dimensional imaging
Implementation Method 2
a mirror is disposed in the distal end of the probe, the structured light projector and the camera positioned to face the mirror, and the mirror positioned to reflect light from the structured light projector directly onto an object being scanned and reflect light from the object being scanned into the camera
Implementation Method 3
including a pattern generator disposed in the optical path between the light source and the projector focal plane that generates a structured light pattern at the projector focal plane
Data Source
AI summary
A system comprises an intraoral scanning device and a processor. The intraoral scanning device comprises a wand including a probe, one or more light projectors disposed in the probe and configured to project a structured light pattern, wherein the structured light pattern comprises first pattern features of a first type and second pattern features of a second type, and two or more cameras disposed in the probe and configured to acquire one or more sets of images. The processor is configured to solve a correspondence problem within each set of images such that first points in 3D space are determined based on a captured subset of the first pattern features and a corresponding projected subset of the first pattern features and second points in 3D space are determined based on a captured subset of the second pattern features and a corresponding projected subset of the second pattern features.