Optical Coherence Tomography Gaussian Spectrum Conversion for Depth Range
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Solution Overview
Problem
Conventional optical coherence tomography (OCT) techniques face challenges in optimizing the imaging possible range in the depth direction while achieving a favorable resolution, as they primarily focus on resolution changes without considering the imaging possible range, leading to suboptimal imaging conditions.
Innovation Solution
The technique involves spectrum conversion of interference light to a Gaussian distribution form, allowing adjustment of the center wavelength and spectrum width to balance resolution and imaging possible range in the depth direction, using a conversion characteristic that shifts the center wavelength of the Gaussian distribution curve relative to the light source spectrum.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the center wavelength of the light source spectrum is shortened and the spectrum width is increased to improve depth direction resolution, then the resolution is improved, but the imaging possible range in the depth direction is reduced
Solution Approach 1:
The patent applies parameter changes by adjusting the center wavelength and spectrum width of the light source spectrum. By optimizing these parameters, the system achieves a balance between depth direction resolution and imaging possible range, resolving the technical contradiction between these two competing requirements.
Solution Approach 2:
The patent introduces dynamic adjustment capabilities that allow the imaging conditions to be optimized in real-time. The system can dynamically change the spectrum characteristics to adapt to different imaging requirements, enabling both high resolution and extended imaging range as needed.
2Reliability
If spectrum conversion is applied to reduce side lobe noise, then image quality is improved, but the imaging possible range in the depth direction is reduced
Solution Approach 1:
The patent optimizes the parameters of the Gaussian window function used in spectrum conversion. By carefully selecting the center wavelength and width of the Gaussian window, the system reduces side lobe noise while minimizing the impact on imaging range, thus resolving the contradiction between image quality and imaging possible range.
3Measurement precision
If the numerical aperture of the objective optical system is increased to improve horizontal direction resolution, then the resolution is improved, but the imaging possible range in the depth direction is reduced
Solution Approach 1:
The patent introduces dynamic adjustment capabilities that allow the imaging conditions to be optimized in real-time. The system can dynamically change the spectrum characteristics to adapt to different imaging requirements, enabling both high resolution and extended imaging range as needed.
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 achieves an optimal balance between resolution and imaging possible range in the depth direction, reducing noise and enhancing image quality by controlling the center wavelength and spectrum width through spectrum conversion.
Implementation Method 1
a light source to be generally used has a spectrum centered on a near-infrared region
Implementation Method 2
interference light occurring between light reflected from the imaging object and reference light is detected
Implementation Method 3
The spectrum of the interference light is Fourier-transformed to acquire information about the imaging object in a depth direction
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
In an imaging technique employing optical coherence tomography, the present invention optimizes an imaging possible range in a depth direction in terms of a relationship with a resolution. An optical coherence tomographic apparatus 1 includes: a light source 21; an interference light generator 22 that branches the light from the light source, causes one branch light to enter an imaging object via an objective lens, collects light reflected from the imaging object with the objective lens, and couples the collected light to different branch light, thereby generating interference light; a detector 26 that detects the interference light; and a signal processor 33 that determines a reflected light intensity distribution of the imaging object on the basis of the spectrum of the detected interference light. The signal processor performs spectrum conversion, having a conversion characteristic with which the light source spectrum is converted to a Gaussian distribution curve, on the spectrum of the interference light, and determines the reflected light intensity distribution by Fourier-transforming a spectrum resulting from the spectrum conversion. In the conversion characteristic, the light source spectrum and the Gaussian distribution curve have center wavelengths differing from each other.