Structured Light Dental Imaging via Scanning Mirror
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Solution Overview
Problem
Fringe projection imaging struggles with tooth translucency and high reflection, leading to inaccurate data due to subsurface scattering and noise, and conventional methods require costly and time-consuming surface coatings, which can mask tooth features and reduce information quality.
Innovation Solution
An intra-oral imaging apparatus using a structured light source with single-axis scanning, employing a fringe pattern generator with a structured light laser diode and a reflective element to scan the tooth surface, and a control logic processor to process images without the need for surface coatings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a coating is applied to the tooth surface to eliminate scattered light effects, then measurement precision is improved, but the process becomes more complex and time-consuming
Solution Approach 1:
The patent extracts and eliminates the harmful scattered light effects through mathematical processing of the captured images, rather than applying physical coatings. The system captures images with scattered light included and then removes the scattering effects computationally, separating the desired surface contour information from the unwanted subsurface scattering artifacts.
Solution Approach 2:
The patent replaces the mechanical/chemical process of applying physical coatings with an optical-computational system. Instead of using paint or reflective powder to modify the tooth surface, the system uses structured light projection combined with image processing algorithms to achieve accurate contour measurement without altering the tooth surface.
2Measurement precision
If a coating is applied to the tooth surface to eliminate scattered light effects, then measurement precision is improved, but the process takes more time
Solution Approach 1:
The patent performs preliminary actions by capturing multiple images with different structured light patterns before processing. The system projects multiple fringe patterns and captures corresponding images in rapid succession, gathering all necessary data before computational processing begins, which streamlines the overall workflow.
Solution Approach 2:
The patent replaces the time-consuming manual coating application process with a rapid optical imaging and computational processing system. The structured light projection and digital image processing occur much faster than manual coating application and drying, significantly reducing the total imaging time while maintaining measurement accuracy.
3Measurement precision
If a coating is applied to the tooth surface, then scattered light effects are reduced, but other tooth problems are masked
Solution Approach 1:
The patent extracts and removes only the scattered light components from the captured images while preserving all other tooth surface information. The image processing algorithms selectively eliminate subsurface scattering artifacts without masking or altering other important dental features, maintaining complete information about the tooth surface.
Solution Approach 2:
The patent introduces computational image processing as an intermediary between light interaction with the tooth and the final measurement result. This intermediary processing step separates the scattered light effects from the true surface contour information, allowing accurate measurement without physically altering the tooth surface with coatings that would mask other features.
4Measurement precision
If conventional fringe projection is used on translucent teeth, then imaging is attempted, but signal-to-noise ratio decreases due to subsurface scattering
Solution Approach 1:
The patent converts the harmful subsurface scattering effect into a manageable signal through structured light projection. By using coherent structured light patterns, the system captures scattering effects in a controlled manner that allows subsequent mathematical separation of scattering artifacts from true surface information, turning the previously harmful scattering into useful measurement data.
Solution Approach 2:
The patent replaces the conventional fringe projection approach that directly measures reflected light with a computational approach that processes captured images to remove scattering effects. Instead of relying on optical filtering or surface modification, the system uses digital image processing to eliminate subsurface scattering artifacts and recover accurate surface contour information.
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 provides accurate and cost-effective three-dimensional imaging of teeth with improved light delivery and reduced noise, enabling precise contour mapping without the need for additional coatings, thus enhancing dental imaging processes.
Implementation Method 1
at least one structured light laser diode that is energizable to emit a patterned light beam
Implementation Method 2
at least one structured light laser diode
Implementation Method 3
at least one reflective element in the path of the emitted patterned light beam and actuable to rotate about an axis to scan the emitted patterned light beam
Implementation Method 4
a detector configured to acquire one or more images of the fringe pattern illumination from the tooth surface
Data Source
AI summary
An intra-oral imaging apparatus for obtaining a contour image of a tooth has a fringe pattern generator energizable to emit a fringe pattern illumination. The fringe pattern generator has (i) at least one structured light source that is energizable to emit a patterned light beam; (ii) at least one reflective element in the path of the emitted patterned light beam and actuable to rotate about an axis to scan the emitted patterned light beam along a tooth surface as fringe pattern illumination. A detector is configured to acquire one or more images of the fringe pattern illumination from the tooth surface. A control logic processor is configured to control the fringe pattern generator for illuminating the tooth and to obtain and process the one or more images acquired by the detector.