Dynamic k-Clock Switching for OCT Imaging Depth
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Solution Overview
Problem
Current Optical Coherence Tomography (OCT) systems face challenges in simultaneously achieving high imaging depth and spatial resolution, particularly in ophthalmic applications, where measuring the full eye length requires compromises in system performance or design constraints, such as using long optical delays or dual optical delays.
Innovation Solution
The implementation of a mode-switching circuitry that allows dynamic switching of the k-clock period in swept-source OCT systems, enabling selective sampling of the OCT interference signal at different rates to adjust the imaging depth without requiring multiple clock generators or opto-mechanical mechanisms, thereby supporting the production of both half-depth and full-depth images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the sampling rate is increased to improve imaging depth, then the imaging depth is improved, but the data processing complexity and time increase
Solution Approach 1:
The system dynamically switches between full-rate and half-rate sampling modes based on the required imaging depth. The k-clock period is adjusted in real-time to match the imaging requirements, allowing the system to optimize between imaging depth and processing time by selecting the appropriate sampling rate for each imaging scenario.
Solution Approach 2:
The sampling rate parameter is changed based on imaging depth requirements. By switching between full-rate sampling (for maximum depth) and half-rate sampling (for reduced processing), the system adapts the sampling parameter to match the specific imaging needs, resolving the contradiction between depth and processing time.
2Length of stationary object
If the k-clock period is extended to increase imaging depth, then the imaging depth is improved, but the spatial resolution deteriorates
Solution Approach 1:
The system dynamically adjusts the k-clock period based on the desired imaging depth while maintaining appropriate sampling density. By switching between full-rate and half-rate modes, the system ensures that spatial resolution is preserved when using extended k-clock periods for increased imaging depth, as the full-rate sampling compensates for the extended period.
Solution Approach 2:
The system uses periodic switching between full-rate and half-rate sampling modes depending on the imaging requirements. When maximum spatial resolution is needed, full-rate periodic sampling is used; when imaging depth is the priority, half-rate periodic sampling is selected, allowing the system to manage the trade-off between depth and resolution.
3Adaptability or versatility
If multiple clock generators are used to achieve flexible sampling rates, then the adaptability is improved, but the device complexity increases
Solution Approach 1:
A single k-clock circuit is designed to perform multiple functions by generating both full-rate and half-rate sampling clocks. The circuit can operate in different modes (full-rate or half-rate) depending on the imaging requirements, eliminating the need for separate clock generators for each sampling rate while maintaining sampling rate flexibility.
Solution Approach 2:
The system generates a phase-shifted replica of the k-clock signal to create the half-rate sampling clock. Instead of using a separate clock generator, a copy of the original k-clock signal is phase-shifted to achieve the desired half-rate sampling, simplifying the device while maintaining adaptability.
4Adaptability or versatility
If opto-mechanical mechanisms are used to adjust imaging depth, then the adaptability is improved, but the device complexity and reliability worsen
Solution Approach 1:
The system replaces opto-mechanical depth adjustment mechanisms with electronic control of the sampling rate. By using digital signal processing and electronic clock generation to adjust imaging depth, the system eliminates complex mechanical moving parts while maintaining the ability to adapt imaging depth to different requirements.
Solution Approach 2:
The system uses its own k-clock circuit to generate both full-rate and half-rate sampling signals, making the depth adjustment capability self-contained without requiring external opto-mechanical mechanisms. The electronic system serves itself by internally generating the necessary clock signals for different imaging depths.
Data Source
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AI summary
Techniques and apparatus for selectively producing half-depth and full-depth OCT images, based on a swept-source OCT interference signal. An example method comprises selecting from a first sampling rate and a second sampling rate, the second sampling rate being twice the first sampling rate, and sampling the swept- source Optical Coherence Tomography (OCT) interference signal at the selected sampling rate, using a k-clock signal having a frequency range corresponding to the first sampling rate, to produce a sampled OCT interference signal. The method further comprises processing the sampled OCT interference signal to obtain an OCT image, such that the resulting OCT image is a half-depth image in the event the first sampling rate is selected and a full-depth image in the event the second sampling rate is selected.