Confocal Imaging Without Field Lens
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Solution Overview
Problem
Confocal imaging systems for three-dimensional surface scanning face challenges due to the use of field lenses, which require accurate alignment, are time-consuming to set up, and introduce inaccuracies due to the enlargement of optics and potential misalignment.
Innovation Solution
A confocal imaging apparatus without a field lens, which uses a non-flat focal surface and a translation mechanism to adjust lens positions, coupled with a field compensator that applies a field curvature model to correct for distortions and changes in focusing settings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If field lenses are used to flatten the imaging field, then flat focal planes are achieved for accurate surface topology, but the optics become enlarged and alignment becomes time-consuming and challenging
Solution Approach 1:
The patent removes the field lens from the confocal imaging system, extracting the component that causes optical enlargement and alignment complexity. By eliminating the field lens, the system achieves the same flat focal plane effect through computational methods rather than optical components, thereby reducing device complexity while maintaining measurement precision.
Solution Approach 2:
The patent replaces the mechanical/optical field lens with a computational field compensator that uses software algorithms to correct field curvature. This substitution eliminates the need for physical field lenses and their associated alignment procedures, transforming a mechanical optimization problem into a computational one that can be solved more easily.
2Measurement precision
If field lenses are used to ensure flat focal planes, then accurate imaging is achieved, but alignment is a time-consuming process
Solution Approach 1:
By removing the field lens from the system, the patent eliminates the alignment procedure that would otherwise be required. The field compensator is pre-configured with calibration data that automatically accounts for field curvature, eliminating time-consuming alignment operations while maintaining imaging accuracy.
Solution Approach 2:
The patent performs field curvature compensation calculations in advance during system calibration, rather than requiring real-time alignment during operation. The field compensator is pre-programmed with the necessary correction data, so that when imaging occurs, the system automatically applies corrections without requiring time-consuming alignment procedures.
3Measurement precision
If field lenses are used in the confocal imaging apparatus, then flat focal planes are achieved, but manufacturing becomes more difficult due to alignment requirements
Solution Approach 1:
The patent eliminates the field lens from the optical path, removing the component that complicates manufacturing through alignment requirements. By substituting the optical field lens with a computational approach, the system becomes easier to manufacture since it requires no precise alignment of additional optical elements.
Solution Approach 2:
The patent replaces the mechanical field lens system with a computational field compensator. This substitution simplifies manufacturing by eliminating the need for precise mechanical alignment of field lenses, as the field curvature correction is achieved through software algorithms that can be calibrated and applied automatically.
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 allows for accurate three-dimensional imaging without the need for field lens alignment, reduces the size and weight of the imaging apparatus, and improves manufacturing ease while maintaining high measurement accuracy.
Implementation Method 1
an array of light beams are directed at a three dimensional object to be imaged and an array of returning light beams are measured
Implementation Method 2
focusing optics are configured to focus the array of light beams onto a non-flat focal surface
Implementation Method 3
a translation mechanism is configured to adjust a location of at least one lens of the focusing optics to displace the non-flat focal surface along an imaging axis
Data Source
AI summary
A system includes a scanner comprising a light source to emit light onto an object, and an image sensor to form a sequence of images of the object under a plurality of different conditions. The system includes a computing device to perform a calibration of the scanner by determining, from the sequence of images, differences in measured coordinates for a plurality of points on the object under the plurality of different conditions, generating or updating one or more compensation models that compensate for inaccuracies of the intraoral scanner based at least in part on the differences in the measured coordinates for the plurality of points of the object between the plurality of different conditions, and storing the one or more compensation models. The one or more compensation models cause the intraoral scanner to be a calibrated intraoral scanner.