Dental Camera Dynamic Projection Patterns for Translucent 3D Scanning
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Solution Overview
Problem
Existing 3D measurement techniques struggle with translucent objects due to reduced contrast and noise interference, leading to difficulties in detecting projected features and correlating images, which is exacerbated by the limitations of image sensor full-well capacities and object noise.
Innovation Solution
A device and method utilizing an optical array generator to generate dynamic patterns with controlled luminous intensity regions, combined with a lens array to project and record these patterns on an object, allowing for noise reduction and increased data density through temporal sequencing and structured illumination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If light intensity is increased to reduce sensor shot noise, then signal-to-noise ratio improves, but the full-well capacity of image sensor pixels is exceeded and object noise cannot be reduced
Solution Approach 1:
The patent applies periodic action by projecting structured light patterns in temporal sequences rather than continuous illumination. Multiple patterns are projected sequentially, allowing the sensor to integrate signals over time without exceeding per-pixel full-well capacity. This temporal multiplexing approach maintains measurement precision while avoiding sensor saturation and reducing object noise through pattern differentiation.
Solution Approach 2:
The patent employs dynamics by using dynamically switchable spatial light modulators that can rapidly change the projected light patterns between frames. This dynamic control allows the system to project different patterns (e.g., sine, cosine, binary coded) in sequence, enabling noise reduction through temporal signal processing while maintaining adaptability to different measurement requirements without requiring increased light intensity.
2Measurement precision
If projected light intensity is increased to improve signal detection, then signal amplitude increases, but diffuse scattered light from object depth also increases making feature detection more difficult
Solution Approach 1:
The patent uses periodic projection of structured patterns (sine, cosine, binary coded) in temporal sequences. By projecting multiple patterns and processing them through temporal signal processing, the system can extract surface reflection signals while suppressing diffuse scattered light from object depth. The periodic modulation allows differentiation between surface-reflected structured light and diffuse internal scattering.
Solution Approach 2:
The patent applies local quality by using spatial light modulators to project structured patterns with locally varying intensities and phases across the object surface. This spatial modulation creates distinct local features in the reflected light that can be traced back to specific surface locations, enabling feature detection even in the presence of diffuse scattered light from translucent materials.
3Loss of information
If structured light patterns are projected onto translucent objects, then 3D surface information can be obtained, but pattern contrast decreases due to light penetration and diffusion
Solution Approach 1:
The patent employs periodic projection of multiple structured light patterns (sine, cosine, binary coded) in temporal sequences. By capturing multiple frames with different patterns and processing them through temporal signal processing algorithms, the system can reconstruct 3D surface information while suppressing the detrimental effects of light penetration and diffusion in translucent objects. The periodic modulation enables extraction of surface reflection components from the composite signal.
Solution Approach 2:
The patent implements feedback through iterative temporal signal processing that uses information from multiple projected patterns to refine the 3D surface reconstruction. The system processes reflected light signals from sequentially projected patterns, using the known pattern structures as reference to extract surface geometry information while compensating for diffuse scattering effects through computational feedback mechanisms.
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
Enhances 3D surface measurement accuracy by reducing noise and increasing data density, enabling effective 3D reconstruction of non-planar objects by analyzing pattern distortions.
Implementation Method 1
a lens array comprising a plurality of lenses constructed to image light from the light source onto an image plane to form the plurality of dynamic patterns
Implementation Method 2
a collimator constructed to direct light of the light source onto the lens array
Implementation Method 3
an imaging sensor arranged within the camera to record a plurality of reflected images formed from reflection of the plurality of dynamic patterns
Implementation Method 4
a first imaging optics arranged within the camera to focus the plurality of dynamic patterns onto a surface of an object to be measured
Data Source
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AI summary
A device, method and system for utilizing an optical array generator to generate dynamic patterns in a dental camera for projection onto the surface of an object, while reducing noise and increasing data density for three-dimensional (3D) measurement. Projected light patterns are used to generate optical features on the surface of the object to be measured and optical 3D measuring methods which operate according to triangulation principles are used to measure the object.