Semiconductor Tunable-Laser OCT Measurement with Compressed Sensing
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Solution Overview
Problem
Existing SS-OCT systems using semiconductor wavelength-tunable lasers face challenges in achieving a uniform wavenumber interval and stability issues, leading to aliasing noise and reduced depth range, making them costly and limiting their applications.
Innovation Solution
Combining a semiconductor wavelength-tunable laser with compressed sensing to control wavelength changes and extract OCT A-scans with high resolution and large depth range, eliminating the need for k-clocks or interpolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a semiconductor wavelength-tunable laser is used in SS-OCT systems, then the cost is reduced, but the wavenumber interval becomes non-uniform and stability issues occur
Solution Approach 1:
The patent changes the sampling strategy from uniform wavenumber sampling to uniform wavelength sampling, accepting non-uniform wavenumber intervals. This parameter change allows the use of low-cost semiconductor wavelength-tunable lasers while maintaining measurement accuracy through compressed sensing reconstruction algorithms that can handle non-uniform sampling patterns.
Solution Approach 2:
The patent replaces expensive, stable external cavity lasers with cheaper semiconductor wavelength-tunable lasers that have inherent stability issues and non-uniform wavelength output. The compressed sensing framework compensates for these deficiencies, enabling the use of lower-cost components without sacrificing overall system performance.
2Ease of manufacture
If a semiconductor wavelength-tunable laser is used, then cost is reduced, but aliasing noise increases and depth range decreases
Solution Approach 1:
The patent introduces compressed sensing reconstruction algorithms as an intermediary processing step between the raw non-uniform wavelength samples and the final OCT image. This intermediary framework transforms the problematic non-uniform sampling data into high-quality depth profiles, effectively filtering out aliasing noise and extending the usable depth range.
Solution Approach 2:
The patent transforms the problem from the wavelength domain to the depth domain through Fourier transformation and compressed sensing reconstruction. By operating in this transformed dimension, the system can recover high-quality signals even when the input wavelength sampling is non-uniform, thereby improving signal quality and depth range.
3Ease of manufacture
If traditional SS-OCT methods are used with semiconductor lasers, then cost is reduced, but k-clocks and interpolation are required
Solution Approach 1:
The patent extracts and eliminates the need for complex k-clock generation and interpolation hardware from the system. By directly sampling at uniform wavelength intervals and using compressed sensing for reconstruction, the system removes these intermediate complexity elements while maintaining or improving measurement accuracy.
Solution Approach 2:
The patent enables the semiconductor wavelength-tunable laser to directly provide the sampling signal through its inherent wavelength tuning mechanism, without requiring external k-clock synchronization. The compressed sensing algorithm then self-adapts to the actual wavelength sampling pattern, making the system more autonomous and less complex.
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-quality OCT A-scans with reduced costs and improved accuracy by using a low-cost semiconductor wavelength-tunable laser and compressed sensing to handle non-uniform wavenumber intervals.
Implementation Method 1
selecting one of a plurality of sample wavelengths as a wavelength of output light of a semiconductor wavelength-tunable laser
Implementation Method 2
interference light obtained by combining and interfering scattered light obtained by irradiating a sample with measurement light, and reference light
Implementation Method 3
an electrical signal obtained by detecting and converting interference light
Data Source
AI summary
A measurement method according to an example embodiment executed by a computer includes: selecting one of a plurality of sample wavelengths as a wavelength of output light of a semiconductor wavelength-tunable laser, and controlling output of the output light in such a way that the selected one sample wavelength discretely and sequentially changes with time; acquiring, for each of the plurality of sample wavelengths, an electrical signal obtained by detecting and converting interference light obtained by combining and interfering scattered light obtained by irradiating a sample with measurement light, and reference light for the measurement light and the reference light obtained by splitting the output light; and deriving a scattering profile of the sample by performing compressed sensing on the electrical signal obtained for each of the plurality of sample wavelengths.