Square-Core Multimode Fiber Endoscopy Without Prior Calibration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing endoscopes using single-mode fiber bundles are bulky and require time-consuming calibration, limiting their use in minimally invasive procedures, and existing multimode fiber endoscopes suffer from information scrambling and shape-dependent calibration issues, making them cumbersome and inflexible.
Innovation Solution
The use of square-core multimode optical fibers with a translational memory effect allows for imaging without prior calibration, enabling flexible and minimally invasive endoscopic imaging by decomposing the optical field into four components and reconstructing the image using a series of illumination patterns and computational methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a bundle of single-mode fibers is used to form an image, then imaging quality is good, but the fiber bundle diameter is large making the endoscope difficult to use in minimally invasive procedures
Solution Approach 1:
The patent changes the fundamental parameter of fiber type from single-mode to multimode, and specifically uses a square-core geometry instead of conventional round cores. This parameter change allows a single multimode fiber to replace a bundle of single-mode fibers, achieving both miniaturization (reduced diameter) and maintained imaging capability through computational methods that exploit the square-core's unique optical properties
Solution Approach 2:
The patent replaces the mechanical/optical scanning system traditionally used with single-mode fiber bundles with a computational imaging approach. By using a single multimode fiber with square core and applying computational algorithms that exploit the translational memory effect, the system eliminates the need for complex mechanical scanning mechanisms while achieving comparable or superior imaging performance
2Length of moving object
If standard round-core multimode optical fibers are used for minimally invasive imaging, then fiber diameter is reduced, but information becomes mixed/scrambled during propagation requiring time-consuming prior calibration
Solution Approach 1:
The patent introduces asymmetry by using a square-core geometry instead of the conventional symmetric round core. This asymmetric square cross-section creates a unique translational memory effect where the spatial distribution of modes preserves information about the input pattern's position and shape. This asymmetric geometry enables calibration-free operation because the square core's modal structure naturally encodes spatial information that can be directly decoded without requiring prior calibration procedures
Solution Approach 2:
The square-core multimode fiber creates a simplified optical mapping where the output pattern is a direct copy or transformation of the input pattern through the fiber's modal propagation. This copying effect, enabled by the square geometry's translational memory effect, allows the imaging system to directly reconstruct the object without requiring calibration to establish the mapping relationship
3Reliability
If rigid multimode optical fibers are used to overcome shape changes after calibration, then calibration stability is improved, but the fields of application and practical uses are greatly limited
Solution Approach 1:
The square-core geometry creates a unique modal structure that is inherently more robust to bending and shape changes compared to round-core fibers. The asymmetric square cross-section produces a translational memory effect that preserves spatial information even when the fiber is bent or deformed, eliminating the need for rigid fiber construction while maintaining calibration stability
4Adaptability or versatility
If multi-core fibers are used to enable flexible imaging, then fiber flexibility is improved, but the cross section is typically 20 to 30 times larger than multimode optical fibers
Solution Approach 1:
The patent changes the fundamental approach by using a single multimode fiber with square core instead of multiple single-mode cores. This parameter change in fiber geometry and modal structure allows the single fiber to carry multiple spatial channels through its modal spectrum, achieving flexibility comparable to multi-core fibers while maintaining a much smaller cross-sectional area
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 flexible, minimally invasive endoscopic imaging with reduced diameter and no calibration requirements, improving user-friendliness and reducing imaging time.
Implementation Method 1
In these square-core multimode optical fibers there is a translational memory effect that allows the calibrating phase to be avoided. Specifically, it has been demonstrated that a memory effect present in the case of scattering media makes it possible to image an object for imaging without prior calibration of the scattering medium.
Data Source
AI summary
The method for imaging an object to be imaged includes: generating, using a lighting device (2), a series of illumination patterns; for each illumination pattern, carrying out a stimulating phase in which translations of the illumination pattern are carried out over an entrance of a square-core multimode optical fiber (4) by means of at least one translating device (3a) of an optical system (3) placed between the lighting device (2) and the entrance of the square-core multimode optical fiber (4), the translations being carried out in a plane parallel to the entrance plane of the square-core multimode optical fiber (4); for each stimulating phase, carrying out an acquiring phase in which the signal generated by the illumination pattern on the object to be imaged (O) placed at the exit of the square-core multimode optical fiber (4) is measured by a signal-measuring device (5; 9); and reconstructing, using a computing device (6), by the signal measured in each acquiring phase, the object to be imaged.