Spectral Filtering K-Clock Signal OCT Artifacts
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Solution Overview
Problem
Swept Source OCT systems suffer from image artifacts due to spurious reflections and imperfect frequency tracking in k-clock modules, leading to suboptimal image quality.
Innovation Solution
The system performs spectral filtering on the sampled k-clock signal to create a reconstructed k-clock signal, which is then used for resampling the interference dataset, reducing artifacts in OCT images by linearizing the data and optimizing the k-clock module's performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If spectral filtering of k-clock signal is performed to reduce artifacts, then image quality improves, but processing complexity increases
Solution Approach 1:
The patent applies spectral filtering to the k-clock signal in advance, before the interference signal is processed. By pre-processing the k-clock signal to remove spurious reflections and frequency tracking errors, the system prepares cleaner reference data that will be used for resampling the interference signal, thereby improving final image quality without adding complex processing steps later in the chain
Solution Approach 2:
The filtered k-clock signal acts as an intermediary between the swept source and the interference signal processing. By introducing this intermediate filtered reference signal, the system mediates the transfer of frequency information while eliminating artifacts, allowing the interference signal to be resampled with higher accuracy without directly confronting the full complexity of raw k-clock imperfections
2Speed
If k-clock module is used for frequency tracking, then scanning speed improves, but manufacturing precision deteriorates due to spurious reflections
Solution Approach 1:
The patent extracts and removes the harmful spurious reflection components from the k-clock signal through spectral filtering. By identifying and eliminating these artifact frequencies in the frequency domain, the system separates the useful frequency tracking information from the harmful reflections, thereby maintaining fast scanning speeds while improving frequency tracking accuracy
Solution Approach 2:
The patent converts the harmful effect of spurious reflections into a benefit by using spectral filtering to identify characteristic artifact frequencies. These previously harmful reflections become identifiable markers that can be selectively removed, and the filtering process itself becomes a useful tool for characterizing and compensating for system-specific imperfections in the k-clock module
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 enhances the accuracy and clarity of OCT images by minimizing artifacts, improving the overall performance of Swept Source OCT systems by compensating for manufacturing imperfections and system-specific differences.
Implementation Method 1
a rendering system that spectrally filters the k-clock dataset into a reconstructed k-clock dataset
Implementation Method 2
resamples the interference dataset into a linearized interference dataset in response to the reconstructed k-clock dataset
Implementation Method 3
an interferometer that generates interference signals from the swept optical signal
Data Source
AI summary
A system and method for spectral filtering of a k-clock signal in a swept-source Optical Coherence Tomography (“OCT”) system to remove artifacts in the k-clock signal. The system synchronizes sampling of the k-clock and interference signals generated from scanning a sample. Using a filtered k-clock signal, the system resamples an interference dataset of the interference signals. The system then performs Fourier transform based processing upon the resampled interference dataset to yield axial depth images of the sample. The system preferably performs the reconstruction, resampling, and associated Fourier-Domain signal processing in software via a Field Programmable Gate Array (“FPGA”) of a rendering system.