Swept-Source OCT Artifact Compensation Using Fourier Reconstruction
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Solution Overview
Problem
Existing swept-source OCT systems suffer from movement artifacts due to slow sweep durations of cost-effective lasers like VCSELs and DFB lasers, which are unsuitable for precise biometric measurements in living eyes, necessitating a cost-effective solution that maintains high sensitivity and reproducibility.
Innovation Solution
A method for signal reconstruction in swept-source OCT systems using adapted algorithms, such as Fourier transforms and fractional Fourier transforms, to compensate for movement artifacts without additional reference signals, particularly for optical coherence interferometry-based systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If cost-effective lasers like VCSELs or DFB lasers are used as light sources, then the system cost is reduced, but the sweep duration increases to greater than 1 ms causing movement artifacts
Solution Approach 1:
The patent changes the temporal parameters of the laser sweep by using cost-effective VCSEL or DFB lasers that can be tuned thermally and electrically, accepting longer sweep durations (>1ms) but compensating through post-processing algorithms to maintain measurement quality
Solution Approach 2:
The patent replaces the need for additional mechanical reference signals or hardware compensation systems with computational algorithms (Fourier transforms, fractional Fourier transforms) that process the measurement signals to remove movement artifacts
2Ease of manufacture
If longer sweep durations are used to reduce laser cost, then measurement artifacts increase due to eye movement, but high sensitivity measurements require short sweep durations
Solution Approach 1:
The patent converts the harmful effect of eye movement during long sweeps into a recoverable signal characteristic by using algorithms that identify and remove movement-induced artifacts, thereby maintaining measurement precision despite longer acquisition times
Solution Approach 2:
The patent uses computational models and algorithms that create virtual reference signals to represent and compensate for eye movement, replacing the need for physical reference measurements
3Measurement precision
If additional reference signals are used to compensate for movement artifacts, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent replaces complex hardware-based reference signal systems with computational algorithms implemented in software, using Fourier transforms and fractional Fourier transforms to compensate for movements without additional optical components or reference channels
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 sensitivity and reproducible biometric measurements by compensating for movement artifacts, making optical biometry accessible and affordable in both industrial and newly industrialized countries.
Implementation Method 1
optical coherence interferometry-based systems
Implementation Method 2
tuned thermally and/or electrically over a wavelength range
Implementation Method 3
tuned thermally and/or electrically over a wavelength range
Data Source
AI summary
A method for compensating the artifacts generated by moving measurement objects in measurement signals of swept-source OCT systems by moving measurement objects. Signal reconstruction is implemented without the aid of additional reference signals in respect of the movement of the measurement object and only by way of especially adapted algorithms. Example methods relate firstly to the especially adapted, Fourier transform-based algorithms for processing the captured measurement signals and secondly to the measurement signals to be captured, in particular to the optical coherence interferometry-based measurement systems used for the production thereof. Although the proposed method is provided for applications in ophthalmology in particular, it can be used, in principle, wherever signals reflected by curved surfaces or backscattered from structures are analyzed.