FD-OCT Imaging via Container Walls
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Solution Overview
Problem
Current Fourier domain optical coherence tomography (FD-OCT) techniques face challenges in obtaining accurate tomographic images of objects within optically transparent containers due to complex conjugate noise from the container walls, requiring complex and expensive apparatus configurations.
Innovation Solution
An imaging apparatus and method that adjusts the focal depth of the objective optical system and the optical path length of the reference light to position the reference plane between the conjugate images of the container walls, effectively eliminating complex conjugate noise by setting the reference plane near the imaging object and optimizing the optical path lengths based on the container's thickness and focal depth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a container wall surface acts as a strong reflection surface for imaging, then the imaging can be performed via the optically transparent container wall, but complex conjugate noise due to reflected light from the container wall surface is superimposed on the tomographic image, causing overlap between the required image of the imaging object and the complex conjugate image of the container wall surface
Solution Approach 1:
The patent changes the optical path length parameter of the reference light to adjust the reference plane position. By setting the reference plane between the first and second surfaces of the container wall, the patent shifts the imaging plane to avoid overlap with complex conjugate images, thereby improving image quality while maintaining the capability to image through the container wall
Solution Approach 2:
The patent uses the complex conjugate image formation principle to predict and avoid noise locations. By understanding that complex conjugate images appear at specific positions based on the reference plane, the patent strategically positions the reference plane to ensure that conjugate images of container walls do not overlap with the desired imaging region
2Measurement precision
If a special apparatus configuration having a plurality of reference systems is used to suppress complex conjugate noise, then the influence of complex conjugate noise due to reflected light from a container wall surface can be suppressed, but the apparatus becomes complicated, enlarged and expensive
Solution Approach 1:
Instead of adding multiple reference systems, the patent simply adjusts the optical path length parameter of the existing single reference light system. This parameter change allows the same apparatus to achieve noise suppression by repositioning the reference plane, avoiding the need for complex multi-reference configurations
Solution Approach 2:
The patent extracts and addresses only the essential element needed for noise suppression - the reference plane position - by adjusting the optical path length. This focuses the solution on a single controllable parameter rather than requiring multiple reference systems, thereby simplifying the apparatus while achieving the desired noise suppression effect
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 allows for high-quality tomographic imaging without the influence of complex conjugate noise from the container walls, improving image quality and simplifying the apparatus configuration, enabling effective noise suppression near the focal plane.
Implementation Method 1
an objective optical system which causes reflected light from the imaging object to be incident on the photo detector
Implementation Method 2
detects interference light generated by interference of signal light obtained by condensing reflected light from the imaging object
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
An imaging apparatus images an imaging object which is stored in a container having an optical transparent wall part tomographically via the wall part. An FD-OCT imaging apparatus sets an optical path length of a reference light in conjunction with a setting of a focal depth such that a position corresponding to the focal depth is between a position conjugate with a first surface and a position conjugate with a second surface in a reflected light intensity distribution representing a relationship between a position in an incident direction of an illumination light and a reflected light intensity. Here, the first surface is a surface on the imaging object side out of surfaces of the wall part. The second surface is another surface on a side opposite to the imaging object out of the surfaces of the wall part.