OCT Spectral Width Switching for Resolution and Field of View
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Solution Overview
Problem
Conventional optical coherence tomography (OCT) systems face challenges in achieving effective measurement of sensitive objects due to the need for expensive components and elaborate adjustments, as well as limitations in sensitivity and total intensity of measuring light.
Innovation Solution
The method involves performing two measurements with different spectral widths of measuring light, where the first spectral width is at least 10% greater than the second, allowing for adjustable axial resolution and field of view by varying the spectral width and dispersion of the measuring light, and using a system with a light source, spectrometer, and controller to optimize structural data acquisition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional OCT systems use fixed spectral width components, then system structure is simple, but axial resolution and field of view cannot be adjusted
Solution Approach 1:
The patent employs dynamic spectral filtering by switching between different bandpass filters with varying spectral widths. The filter selection is controlled dynamically based on the desired axial resolution and field of view, allowing the system to adapt its characteristics without permanent structural changes. This resolves the contradiction by making the system adaptable through temporal switching rather than requiring multiple fixed configurations.
Solution Approach 2:
The invention changes the spectral width parameter of the measuring light by selecting different bandpass filters. Each filter has a specific spectral width that directly determines the axial resolution and field of view. By varying this parameter through filter switching, the system achieves adjustable performance characteristics while maintaining a relatively simple overall structure.
2Reliability
If high intensity measuring light is used, then signal detection sensitivity is improved, but damage to sensitive biological objects increases
Solution Approach 1:
The patent optimizes the spectral width parameter of the measuring light to match the specific imaging requirements. By using a spectral width that is no broader than necessary for the desired axial resolution, the system minimizes the total light intensity required while maintaining adequate signal detection sensitivity. This reduces harmful effects on sensitive biological objects like the human eye.
Solution Approach 2:
The invention applies partial spectral coverage by using bandpass filters that transmit only the necessary wavelength range for the imaging task. Instead of using broadband light that covers excessive spectral ranges, the system uses partial spectral action with optimized bandwidth, reducing total energy exposure while maintaining detection sensitivity for the specific application.
3Measurement precision
If broadband measuring light is used, then axial resolution is improved, but axial field of view decreases
Solution Approach 1:
The patent dynamically switches between different bandpass filters with varying spectral widths depending on the imaging requirements. When high axial resolution is needed, a filter with narrower spectral width is selected. When larger field of view is required, a filter with broader spectral width is used. This dynamic adaptation resolves the contradiction by allowing the system to optimize for either resolution or field of view based on the specific imaging task.
Solution Approach 2:
The invention changes the spectral width parameter to balance axial resolution and axial field of view. By selecting appropriate spectral widths from available bandpass filters, the system can achieve the desired axial resolution while maintaining an adequate axial field of view for the specific application, rather than being constrained to a fixed trade-off.
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 enables improved axial resolution and adjustable axial field of view, reducing the total power of measuring light required while maintaining sensitivity, suitable for investigating sensitive biological objects like the human eye.
Implementation Method 1
a reflectivity within a volume of the object depends on a refractive index and a gradient of the refractive index of the material within the particular volume of the object. Also, an orientation of an interface between two volume portions within the object having different refractive indices relative to a direction of a beam path of the measuring light influences the amount of reflected light emanating from the object
Implementation Method 2
the first portion of the measuring light having interacted with the object at a certain depth and the second portion of the measuring light beam being reflected at the reflecting surface arranged at a certain position are superimposed and detected
Implementation Method 3
spectrally dispersing the superimposed light, and detecting intensities of plural spectral portions of the spectrally dispersed light
Data Source
AI summary
Frequency domain optical coherence tomography (FD-OCT) systems and methods are provided. Thereby, a first measurement and a second measurement is performed, wherein in the first measurement an object region is illuminated by measuring light having a spectrum with a first spectral width and in the second measurement the object region is illuminated with measuring light having a spectrum with a second spectral width, wherein the first spectral width is at least 10% greater than the second spectral width. Further, during the first measurement intensities of spectral ranges of light having interacted with the object and being superimposed with reference light are detected, wherein a width of these spectral ranges is greater than a corresponding width during the second measurement. Thus, switching an axial field of view of structural information of the object across a depth direction is enabled upon minimizing radiation damage at the object.