Stereo Camera Dental Imaging Without Structured Light
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Solution Overview
Problem
Current 3D measurement technologies in the dental field are hindered by complexity, high cost, and inaccuracy due to the need for mechanical, optical, or electro-optical scanning, which requires camera movement, leading to blurring and limited depth of field, and often necessitate a 'coating' on teeth, causing discomfort and inaccuracy.
Innovation Solution
A miniaturized, color stereoscopic system with CCD or CMOS sensors and LED lighting, allowing for instantaneous 3D reading without structured light projection, enabling precise digitization of dental arches in a single shot without additional coatings, using a fixed optical system and electronic data management for real-time 2D or 3D visualization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If mechanical, optical or electro-optical scanning is used to measure the surface, then measurement capability is achieved, but the system becomes complex and expensive
Solution Approach 1:
The patent extracts the scanning function from the camera system by using a fixed camera position and instead scanning the surface with projected light patterns (fringes, masks, or structured light). This separates the measurement function from the imaging function, allowing a simple fixed camera to capture multiple views while the projection system handles the scanning operation.
Solution Approach 2:
The patent combines multiple functions into integrated units: the camera is merged with projection systems (mask projector, fringe projector, or structured light projector) to form a single measurement device. This integration reduces the number of separate components and simplifies the overall system architecture while maintaining measurement precision.
2Area of stationary object
If camera movement is used to capture different views, then complete surface coverage is achieved, but blurring and loss of focus occur
Solution Approach 1:
The patent makes the lighting system dynamic instead of the camera. Projected masks, fringes, or structured light patterns move across the surface to illuminate different areas, while the camera remains fixed in position. This dynamic illumination approach allows complete surface coverage without moving the camera, thereby avoiding blurring and focus loss.
Solution Approach 2:
The patent adds temporal dimension to the measurement process by capturing multiple images at different time points corresponding to different positions of projected patterns. Instead of moving the camera in space to capture different views, the system uses time-sequence imaging with moving light patterns to achieve the same coverage while keeping the camera stationary.
3Measurement precision
If structured light projection is used for measurement, then 3D information is obtained, but the system requires complex calibration and has limited depth of field
Solution Approach 1:
The patent inverts the traditional approach by using a fixed camera and moving the projection patterns instead of using a moving camera with fixed projection. This inversion simplifies the calibration requirements because the camera position remains constant, eliminating the need for complex camera movement calibration while maintaining 3D measurement capability through the dynamic projection system.
4Measurement precision
If coating is applied on teeth for measurement, then measurement accuracy is improved, but patient comfort is reduced and additional errors are introduced
Solution Approach 1:
The patent uses the natural optical properties of teeth and oral tissues themselves for measurement without requiring any external coating or preparation. The system captures and analyzes the inherent color, reflectivity, and geometric features of the oral structures, allowing the measurement process to serve itself using the object's own characteristics rather than requiring additional materials that cause discomfort or introduce errors.
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 solution provides a cost-effective, accurate, and comfortable method for precise 3D dental imaging, eliminating the need for camera movement and coatings, enabling dynamic color visualization and analysis of subcutaneous tissue with improved precision and reduced complexity.
Implementation Method 1
modulated lighting used with LEDs of one or more wavelengths
Implementation Method 2
electronic sensors of the CCD or color Cmos type
Data Source
Figure 1~2c
Figure 2d~3a
Figure 3b~3c
AI summary
Device for taking three-dimensional and temporal optical imprints in colour which consists in a three-dimensional dental imaging device that does not employ structured light projection. It comprises: a stereo camera composed of at least two CCD or CMOS colour sensors in preset positions; an optical system of fixed and preset focal length; an LED lighting system; and an electronic system located behind or near said sensor, controlling the latter but also the LEDs illuminating the imprint capture region, and which comprises a central processing unit and a card for controlling said LEDs. The sensors are distributed over all or part of a dental arch, being placed in a sort of optical impression tray allowing a complete image of the arch to be captured in a single exposure.