Endoscope Depth Separation Using Structured Illumination
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Solution Overview
Problem
Current endoscope systems face challenges in effectively separating information about the surface and interior of an object, particularly in biological tissues, due to the overlap of specular, surface-scattered, and internal-scattered light components, which hinders clear imaging of different depths within the tissue.
Innovation Solution
The endoscope system employs a dual illumination approach with first and second illumination lights having different spatial frequency patterns and intensity distributions, where the first illumination light has a spatially non-uniform distribution with periodically repeated light and dark portions, and the second illumination light is spatially uniform. The system includes an intensity-distribution changing unit that alters the pattern over time, allowing the imaging unit to capture multiple images, and an image-processing unit that separates information for different depths using these images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If a single illumination light is used to image the subject, then the imaging process is simple, but information about different depths (surface and interior) cannot be effectively separated
Solution Approach 1:
The illumination light is segmented into multiple components with different spatial frequencies. The first illumination light contains high-spatial-frequency components that primarily reflect from the surface, while the second illumination light contains low-spatial-frequency components that penetrate deeper into the tissue. This segmentation allows separate capture of surface and interior information.
Solution Approach 2:
The patent introduces a spatial frequency dimension to the illumination light. By using illumination lights with different spatial frequency characteristics, the system can differentiate between surface reflections and interior transmissions, adding a new dimension for depth discrimination beyond traditional imaging methods.
2Measurement precision
If high-spatial-frequency structured illumination light is used to separate surface and interior information, then depth information separation is improved, but the imaging process becomes more complex and requires multiple images
Solution Approach 1:
The patent uses periodic structured illumination patterns with different spatial frequencies. By alternating between high-spatial-frequency and low-spatial-frequency patterns in a periodic manner, the system can capture multiple types of information efficiently. The image processing portion then processes these periodically captured images to extract depth-resolved information.
3Loss of information
If multiple images with different illumination patterns are captured, then information about different depths can be separated, but the imaging time increases
Solution Approach 1:
The patent performs preliminary separation of light components by capturing images under different illumination conditions (high-spatial-frequency and low-spatial-frequency). The image processing portion then processes these pre-captured images to separate surface and interior information, avoiding the need for time-consuming post-acquisition separation methods.
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 precise separation and processing of image information for the surface and deep layers, enhancing visibility of structures within the tissue by effectively removing noise from specular light and improving the clarity of the synthesized image.
Implementation Method 1
a first illuminating portion that radiates first illumination lights, which have a spatial intensity distribution in which light portions and dark portions are periodically repeated in a beam cross-section that is orthogonal to an optical axis
Implementation Method 2
the first illuminating portion has an intensity-distribution changing portion that changes the intensity distribution over time so that positions of the light portions and the dark portions on a surface of the subject are exchanged with each other
Implementation Method 3
an imaging unit that images first illumination images, which are images of the subject irradiated with the first illumination light, and a second illumination image, which is an image of the subject irradiated with the second illumination light
Implementation Method 4
the image-processing portion has a separating-processing portion that separates three of image information for different depths of the subject from the at least four images
Implementation Method 5
an image-synthesizing portion that processes the second illumination image by using image information other than the image information about the outermost surface side of the subject among the three of image information separated by the separating-processing portion
Data Source
AI summary
An endoscope system according to the present invention includes: a first illuminating portion that emits first illumination lights having low-spatial-frequency and high-spatial-frequency and changes the intensity distribution of the first illumination lights over time; a second illuminating portion that emits a second illumination light; an imaging unit that images first and second illumination images of an subject respectively illuminated by the first and second illumination lights; and an image-processing portion that processes the first and second illumination images. The imaging unit images four images including images that correspond to the first illumination lights having low-spatial-frequency and high-spatial-frequency and images in which light and dark portions of the first illumination lights are exchanged with each other. The image-processing portion separates three image information for different depths, and processes the second illumination image by the image information other than the image information about the outermost surface side.