Phase-Sensitive OCT Noise Correction for Acoustic Vibration Detection
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Solution Overview
Problem
Phase-sensitive optical coherence tomography (OCT) systems face challenges in accurately detecting acoustic vibrations due to contamination by random broadband noise and motion noise, particularly in clinical settings where long signal acquisition times are impractical.
Innovation Solution
The method involves processing phase-sensitive OCT measurements to suppress sinusoidal signals associated with acoustic stimuli, estimate and subtract motion noise from vibrographic data, thereby generating noise-corrected vibratory response data for improved signal-to-noise ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If signal averaging is used to reduce random broadband noise, then measurement precision improves, but acquisition time increases significantly
Solution Approach 1:
The acquired signal is segmented into multiple portions, each processed independently to extract vibratory information. By dividing the signal into segments and processing them separately, the system achieves noise reduction without requiring excessively long total acquisition times, resolving the contradiction between measurement precision and acquisition time.
Solution Approach 2:
The method utilizes the periodic nature of the acoustic stimulus and resulting vibrations to synchronize signal processing. By leveraging the known periodicity of the stimulus, the system can extract vibratory signals more efficiently from shorter acquisition windows, reducing the need for prolonged averaging while maintaining precision.
2Reliability
If longer acquisition times are used to average down noise, then signal-to-noise ratio improves, but clinical applicability deteriorates
Solution Approach 1:
The system applies a known acoustic stimulus with predetermined frequency and duration before measurement. This preliminary action creates a controlled vibratory response that can be easily distinguished from noise, enabling reliable measurements in shorter acquisition times suitable for clinical settings.
Solution Approach 2:
The patent replaces traditional mechanical vibration measurement methods with optical detection using OCT. This substitution enables non-contact, highly sensitive vibratory measurements that can be performed rapidly without mechanical coupling, improving both signal-to-noise ratio and clinical applicability.
3Measurement precision
If motion noise suppression is implemented, then measurement accuracy improves, but processing complexity increases
Solution Approach 1:
The method extracts and isolates the vibratory signal component at the known stimulus frequency from the total measured signal. By separating the desired vibratory response from motion noise and other interference through frequency-domain analysis, the system improves measurement accuracy while keeping processing manageable.
Solution Approach 2:
The patent introduces an intermediary processing step that estimates motion noise characteristics from the acquired signal and subtracts this estimate from the total signal. This intermediary estimation and subtraction process effectively reduces motion noise while maintaining reasonable processing complexity.
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 approach significantly reduces noise interference, allowing for faster and more accurate detection of acoustic vibrations with improved signal quality, enabling shorter acquisition times and enhanced clinical applicability.
Implementation Method 1
the sinusoidal motion of a structure located at a particular pixel in the image produces a sinusoidal phase variation between successive A-lines produced by taking the discrete Fourier transform (DFT) of the sampled interferogram
Implementation Method 2
applying an acoustic stimulus at a known frequency and performing phase-sensitive optical coherence tomographic measurements to obtain a set of interferograms
Data Source
AI summary
Systems and methods are provided for performing phase-sensitive optical coherence tomographic (PS-OCT) measurements involving the vibrographic response of an acoustic stimulus. Detected signals are processed to provide sampled time-dependent vibrographic data characterizing a vibratory amplitude and phase response over one or more periods of the acoustic stimulus. The sampled time-dependent vibrographic data is processed to suppress the sinusoidal signal component associated with the acoustic stimulus, thereby providing a residual data associated with noise. The residual data is processed to obtain an estimate of the motion noise, and the motion noise is subtracted from the sampled time-dependent vibrographic data in order to provide noise-corrected vibrographic data. The noise-corrected vibrographic data can be processed to obtain one or more vibrographic measures and/or one or more images.