Chromatic Confocal 3D Measurement via Spectral Referencing
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Solution Overview
Problem
Current chromatic confocal techniques face limitations in achieving high spectral resolution for three-dimensional measurement of objects, particularly in capturing the entire shape of an object within a single image frame, and are complex in evaluation due to lenticular direct coupling methods.
Innovation Solution
A chromatic confocal system utilizing a planar array of polychromatic point light sources, a beam splitter, and a detector matrix with spectral referencing for calibration, allowing for simultaneous depth measurement across various object spaces with improved precision by generating spectrally defined reference light bundles and using a refractive element for wavelength-dependent depth resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a spectrometer is added to obtain chromatic confocal signals via wavelength, then spectral resolution is improved, but device complexity increases
Solution Approach 1:
The patent extracts only the essential spectral dispersion function from a complete spectrometer system by using a diffraction grating combined with a linear array detector, eliminating unnecessary components while maintaining spectral resolution capability for chromatic confocal measurements
Solution Approach 2:
The diffraction grating serves multiple functions: it disperses wavelengths for spectral analysis, enables chromatic confocal depth measurement, and works with standard linear array detectors commonly available in imaging systems, reducing the need for specialized equipment
2Measurement precision
If lenticular direct coupling is used for spectral analysis, then spectral resolution is improved, but evaluation complexity increases
Solution Approach 1:
The patent replaces the mechanical lenticular direct coupling system with a diffraction grating-based optical system that produces linearly dispersed spectra, substituting complex mechanical evaluation with simpler optical geometry and linear detector readout
Solution Approach 2:
The patent changes the spectral dispersion parameter from the complex lenticular coupling mechanism to a diffraction grating equation-based system, where wavelength separation follows a predictable linear relationship with detector position, simplifying data interpretation
3Device complexity
If three color filters are used for spectral analysis, then device complexity is reduced, but spectral resolution deteriorates
Solution Approach 1:
The patent uses a diffraction grating to create multiple spectral copies across the linear detector array, with each detector element receiving light from a specific wavelength range, effectively copying the spectral information into spatial distribution without requiring multiple filter channels
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
Enables fast and robust three-dimensional measurement with significantly higher spectral resolution than traditional methods, capable of capturing detailed geometrical information of objects, including microscopic features like teeth, within a single camera frame, while maintaining precision and reducing computational complexity.
Implementation Method 1
at least one element having a refractive power that is wavelength-dependent for chromatic depth resolution
Implementation Method 2
a beam splitter, at least one element having a refractive power that is wavelength-dependent
Data Source
AI summary
A chromatic confocal technique and apparatus for the rapid three-dimensional measurement of an object shape, particularly of a tooth in a patient's jaw, using an array of polychromatic point light sources, a planar detector matrix, a beam splitter for lateral spectral separation, and an objective for illuminating and recording the object. Spectral defined reference light bundles are generated, injected into the detection beam path via a reference beam path and, following spectral splitting, are focused on the detector matrix as reference image points, wherein laterally shifted sub-matrices are numerically defined on the detector matrix for spectral analysis of the object light, which sub-matrices are implemented as spectral cells for three-dimensional measurement of the shape of the object.