Coherent Fiber Bundle Calibration for Interference Correction
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Solution Overview
Problem
Flexible fiber optic endoscopes suffer from low image contrast due to pixelation, crosstalk, and multimode light guidance, which limits image sharpness and prevents direct access to phase information, making it difficult to achieve coherent illumination and accurate depth measurements.
Innovation Solution
A method for in-situ calibration of coherent fiber bundles using a virtual light source (guide star) to determine the transmission matrix, allowing for interference correction and phase shift compensation without complex adjustment steps, enabling the use of fiber bundles as coherent phased arrays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If imaging optics (lens system) are integrated to reduce pixel pitch, then image resolution is improved, but device size and complexity increase significantly
Solution Approach 1:
The patent replaces mechanical imaging optics (lenses) with a computational approach using a transmission matrix to achieve super-resolution imaging. The transmission matrix, determined through calibration, enables sub-pixel resolution without requiring physical imaging elements, thus avoiding the size and complexity penalties of integrated optics.
Solution Approach 2:
The patent changes the operational parameters of the fiber bundle by determining a transmission matrix that characterizes the optical properties of individual fibers. This mathematical transformation allows the system to resolve features below the diffraction limit and pixel pitch without modifying the physical structure or adding imaging optics.
2Adaptability or versatility
If conventional fiber bundles are used for flexibility, then adaptability is improved, but phase information access is lost
Solution Approach 1:
The patent implements a feedback mechanism where the transmission matrix, determined through calibration using a known test object, is used to compensate for phase distortions in subsequent imaging. This feedback loop restores access to phase information by mathematically correcting the optical path differences introduced by the flexible fiber bundle.
Solution Approach 2:
The patent performs preliminary calibration to determine the transmission matrix before actual imaging. This preliminary action characterizes the optical properties of each fiber in the bundle, enabling subsequent phase correction and interference correction without requiring real-time adjustment during imaging.
3Measurement precision
If calibration is performed separately from observation, then measurement precision is improved, but productivity decreases
Solution Approach 1:
The patent merges the calibration process with the observation process by using the same optical path and detector. The calibration is performed in-situ within the endoscope system using a test object, and the resulting transmission matrix is immediately applied to subsequent imaging, eliminating the need for separate calibration procedures and enabling continuous operation.
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 improves image quality by directly measuring simple phase shifts, allowing for interference correction and enabling high-resolution imaging without the need for complex calibration, and allows for simultaneous calibration and observation, reducing the size and complexity of endoscopic systems.
Implementation Method 1
A coherent bundle of optical fibers, in particular a flexible coherent bundle of optical fibers, is illuminated with light from a light source for the purpose of detecting an object
Implementation Method 2
means for partial reflection of light emitted by the light source are arranged at a distance from the distal facets of the optical fibers of the bundle
Implementation Method 3
means for detecting the spatial intensity distribution of light emitted by the virtual light source and disturbed by transmission via the distally illuminated region of the coherent bundle of optical fibers
Implementation Method 4
The calibration is carried out at least for determining and evaluating system function of the fiber bundle, in particular by determining a transmission matrix
Data Source
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AI summary
The invention relates to a method and a fiber optic system (1) for illuminating and detecting an object with light, comprising the in-situ calibration of a fiber bundle (3) and the interference-corrected illumination or interference-corrected detection of an object (9), particularly for endoscopic and microscopic applications. The invention allows the direct determination of the single phase distortion of the light caused by transmission via the fiber bundle (3) for the purpose of calibrating the fiber bundle (3), thereby offering an improved method for determining the system function of a fiber bundle (3) compared to the prior art of measuring the double phase distortion. The system function is used for interference correction during illumination or detection of the object (9).