Dynamic Interferometric Surface Probe for Noise-Free 3D Mapping
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Solution Overview
Problem
Interferometry is limited in utility due to phase noise from sources like thermal variations, air turbulence, and electromagnetic interference, requiring cumbersome equipment and controlled environments, which hinders its widespread application.
Innovation Solution
A dual interferometer system with identical interferometers sharing a common reference object and symmetric positioning around a target, capturing simultaneous interferograms to differentially minimize noise, yielding substantially noise-free phase information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional interferometry is used to achieve high sensitivity measurements, then measurement precision is improved, but phase noise from environmental factors increases
Solution Approach 1:
The patent uses a reference object that is a copy or replica of the target object, placed in a controlled environment. By comparing the interferometric measurements of the target object (in noisy environment) with the reference object (in controlled environment), the system can isolate and eliminate phase noise caused by environmental factors while preserving the actual surface features of the target object.
Solution Approach 2:
The reference object serves as an intermediary that experiences the same environmental phase noise as the target object but without the actual surface variations. By subtracting the reference measurements from target measurements, the common-mode phase noise is eliminated, leaving only the true surface information.
2Adaptability or versatility
If interferometry is performed in uncontrolled environments to increase adaptability, then ease of operation is improved, but measurement precision deteriorates due to phase noise
Solution Approach 1:
The system places a reference object (copy of the target) in a controlled environment chamber while the target remains in the uncontrolled environment. This allows the measurement system to operate in adaptable, real-world conditions while the reference copy experiences only controlled conditions, enabling post-processing noise removal.
Solution Approach 2:
The patent introduces a temporal dimension by taking measurements at different times (target in noisy environment, reference in controlled environment) and combining them through differential processing. This time-separated measurement approach allows noise cancellation while maintaining environmental adaptability.
3Measurement precision
If multiple interferometers are used to reduce phase noise through differential measurement, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent combines the target object measurement path and reference object measurement path into a single interferometer system that alternates between measuring the target and reference. This merging approach achieves differential noise cancellation without requiring two completely separate interferometer systems, thereby reducing overall device complexity.
Solution Approach 2:
The system uses periodic action by alternately measuring the target object and reference object in a repeating cycle. This periodic switching allows a single interferometer to collect both target and reference data under different environmental conditions, enabling differential noise removal while using minimal hardware.
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 high-resolution three-dimensional topographical measurements in uncontrolled environments by effectively isolating and minimizing phase noise, allowing for precise three-dimensional modeling of objects.
Implementation Method 1
the reflected light waves from each object are combined to cause interference patterns
Implementation Method 2
A coherent light source typically illuminates both a target object and a reference object
Data Source
AI summary
Systems and methods for generating high-resolution three-dimensional topographical measurements using differential interferometry are disclosed. Multiple interferometers transmit coherent light, which may comprise diffraction fringes, along similar optical paths to physical target and reference objects to be measured. The target object may vary in scale, such as a tooth at a smaller scale or a geographic region at a larger scale. An imaging device captures interferograms containing phase information from the target object, the reference object, and various noise sources such as thermal variations, air turbulence, micro-scatterers, external light sources, mechanical vibrations, and electromagnetic interference. Common-mode noise from the interferograms is effectively canceled out, yielding substantially noise-free phase information from the target object that can be processed to produce a three-dimensional target object model. The disclosure is of particular utility with portable instruments since the typical noise sources limiting the use of interferometry outside a controlled environment are largely eliminated.