FD-OCT Imaging Apparatus Wall Reflection Noise Reduction
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Solution Overview
Problem
In FD-OCT imaging, strong reflections from container walls introduce complex conjugate noise that overlaps with the imaging object's signal, making it difficult to obtain accurate tomographic information without a complex and expensive apparatus configuration.
Innovation Solution
The technique involves setting the focal depth of the objective optical system such that the distance from the container wall to the focal point is less than the wall's thickness, and adjusting the reference light's optical path length to match the illumination light's path, effectively separating the complex conjugate image of the container wall from the imaging object's image.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If imaging is performed via the container wall surface, then the imaging object can be observed through the transparent container, but complex conjugate noise from the container wall reflection overlaps with the imaging object signal
Solution Approach 1:
The patent changes the optical path length parameter of the reference light to match the distance from the light source to the first surface of the container wall. This parameter adjustment shifts the reference plane position, causing the complex conjugate image of the wall surface to appear at a different depth location that does not overlap with the imaging object, thereby eliminating noise while preserving imaging capability
Solution Approach 2:
The patent resolves the overlap problem by utilizing the depth dimension in the tomographic image. By adjusting the reference light optical path length, the complex conjugate image is relocated to a different depth position, separating it from the imaging object in the depth dimension and eliminating interference
2Measurement precision
If a prior art noise removal method is used, then complex conjugate noise can be reduced, but the apparatus becomes complicated and expensive
Solution Approach 1:
The patent makes the existing reference light system serve a dual function: both providing reference light for interference and compensating for complex conjugate noise. By simply adjusting the optical path length of the existing reference light, the system achieves noise reduction without requiring additional reference systems or complex apparatus modifications
Solution Approach 2:
The reference light is made multi-functional by having it perform both its standard role in generating interference patterns for tomographic imaging and an additional role of compensating for complex conjugate noise through optimized optical path length matching
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 eliminates the influence of complex conjugate noise near the focal depth, allowing for high-quality tomographic imaging of the object without the need for a complex apparatus configuration, by positioning the reference plane to avoid overlap with the object's image.
Implementation Method 1
detecting interference light generated by the interference of signal light obtained by condensing reflected light from the imaging object
Implementation Method 2
signal light obtained by condensing reflected light from the imaging object emitted via the wall part by an objective optical system
Data Source
AI summary
The present invention aims to obtain a tomographic image free from image noise due to reflection on a container wall surface and having a good image quality by a simple configuration. In a FD-OCT imaging apparatus which images an imaging object stored in a container having an optical transparent wall part tomographically, when the focal depth is set such that a distance D from a first surface Sa of the wall part on the side of the imaging object to a focal point FP of the objective optical system is smaller than a predetermined threshold value smaller than a thickness T of the wall part, the distance between a second surface Sb of the wall part on a side opposite to the imaging object out of the wall surfaces and a reference plane which is perpendicular to the optical path of the illumination light and to which an optical path length is equal is set a value equal to the thickness of the wall part.