OCT Ear Vibration Measurement Using Reference Phase Tracking
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Solution Overview
Problem
Existing techniques for determining vibration amplitudes of ear structures are inefficient and imprecise, particularly when measuring larger areas, due to phase discrepancies and echo interference, requiring lengthy measurement times and inaccurate results.
Innovation Solution
A system and method using an OCT device to project measurement and reference beams on multiple points and a reference point, respectively, to determine vibration amplitudes based on relative positions and motion phases without needing multiple acoustic periods, allowing for simultaneous measurement and correction of unwanted movements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the acoustic stimulus and OCT measurement are linked by simultaneous activation through a trigger signal, then the phase of the acoustic wave when emitted may be known, but the phase of the acoustic wave when reaching the part of the ear is not known, causing phase discrepancy and measurement error
Solution Approach 1:
A reference beam is introduced as an intermediary element that measures the motion phase of a reference point on the ear. This reference beam acts as a mediator between the acoustic stimulus and the measurement beam, providing the missing phase information without requiring direct measurement of the acoustic wave at the measurement location.
Solution Approach 2:
The system changes the measurement parameter from directly measuring acoustic wave phase to measuring the motion phase of reference points using optical beams. By transforming the measurement approach from acoustic domain to optical domain, the system avoids the phase loss problem inherent in acoustic measurements.
2Measurement precision
If measurements are taken during at least one full acoustic period to determine vibration amplitude, then the chance of measuring maximum amplitude increases, but the measurement time becomes very long when multiple measurement points are to be measured
Solution Approach 1:
The motion phase of reference points is measured continuously and stored in advance. When determining vibration amplitude at measurement points, the system uses pre-acquired reference signal data to calculate amplitudes without requiring prolonged measurements at each point, thus reducing total measurement time while maintaining accuracy.
Solution Approach 2:
The reference beam serves multiple functions: it provides phase information for amplitude calculations, enables determination of vibration characteristics at multiple measurement points simultaneously, and reduces the need for repeated measurements. This multi-functional approach allows the system to achieve high measurement precision across multiple points without proportionally increasing measurement time.
3Area of stationary object
If the measurement beam is projected on multiple measurement points to cover larger areas, then the diagnostic capability is enhanced, but the measurement time increases significantly
Solution Approach 1:
Reference points distributed across the measurement area serve as intermediaries that provide local phase information. By measuring motion phases at these reference points and using them to calculate amplitudes at nearby measurement points, the system can cover large areas efficiently without requiring prolonged measurements at each location.
Solution Approach 2:
The measurement area is segmented into multiple zones, each with its own reference points. This segmentation allows the system to process and calculate vibration characteristics for different areas independently and in parallel, improving overall measurement efficiency while maintaining comprehensive area coverage.
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 rapid and accurate determination of vibration amplitudes across large areas of the ear, reducing measurement time and improving precision by using shared OCT components and optimizing beam projections.
Implementation Method 1
OCT, or optical coherence tomography, enables vibrographic measurements of parts of the ear
Implementation Method 2
movements of that part of the ear may be measured in response to an external stimulus, such as a sound wave
Data Source
AI summary
The invention provides a system for determining vibration amplitudes of a structural element of the car, comprising: an acoustic stimulator, configured to generate an acoustic stimulus having an acoustic period to induce vibrations of the structural element; at least one OCT device, configured to measure a measurement signal representative for relative positions of measurement points on the structural element during the vibrations by projecting a measurement beam on the measurement points and to measure a reference signal representative for a motion phase of the structural element by projecting a reference beam on a reference point on the car: and a processing unit, configured to determine vibration amplitudes of the measurement points on the basis of the reference signal and the measurement signal, wherein the projections of the measurement beam and the reference beam are related in time, such that a motion phase represented in the reference.