Endoscope System Oxygen Saturation Imaging Two-Wavelength Normalization
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Solution Overview
Problem
Existing endoscope systems for visualizing oxygen saturation levels in blood vessels face challenges in maintaining a high frame rate during imaging, leading to reduced followability of motion images due to the need for acquiring and processing image information across multiple wavelengths.
Innovation Solution
An endoscope system that includes an image signal acquisition device for white light reflection and an oxygen saturation level generator, which uses normalized signals from two wavelengths to create pseudo-color images of blood vessels, enhancing blood vessel visibility without lowering frame rate by reducing the number of wavelengths required.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If three wavelengths are used to acquire image information for oxygen saturation level visualization, then measurement precision of oxygen saturation level is improved, but frame rate is lowered and followability of motion image is reduced
Solution Approach 1:
The patent extracts only the essential wavelength components needed for oxygen saturation measurement. Instead of using three wavelengths as in conventional technology, the invention identifies that two specific wavelength ranges (first wavelength range where oxyhemoglobin absorption > deoxyhemoglobin absorption, and second wavelength range where deoxyhemoglobin absorption > oxyhemoglobin absorption) are sufficient to calculate oxygen saturation level, thereby eliminating the need for the third wavelength and maintaining high frame rate
Solution Approach 2:
The patent changes the measurement parameters by selecting specific wavelength ranges based on the absorption characteristics of hemoglobin. By choosing wavelengths where the absorption coefficient relationship between oxyhemoglobin and deoxyhemoglobin is maximally different (first wavelength range and second wavelength range), the system achieves accurate oxygen saturation measurement with only two wavelengths, improving frame rate while maintaining measurement precision
2Measurement precision
If three wavelengths are used to acquire image information, then oxygen saturation level can be calculated accurately, but device complexity increases due to multiple light sources and filters
Solution Approach 1:
The patent removes the unnecessary third wavelength component from the system. By analyzing the absorption characteristics of hemoglobin, the invention determines that only two wavelength ranges are needed to obtain the ratio of oxyhemoglobin to deoxyhemoglobin concentrations, thereby simplifying the device structure while maintaining calculation accuracy
Solution Approach 2:
The patent makes the two-wavelength system universally functional for oxygen saturation measurement by selecting wavelength ranges that provide sufficient contrast between oxyhemoglobin and deoxyhemoglobin absorption. This universal approach using two wavelengths replaces the more complex three-wavelength system, reducing device complexity without sacrificing measurement capability
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
The system effectively visualizes oxygen saturation levels in blood vessels at a higher frame rate than previous methods, ensuring accurate and clear imaging without the need for three wavelengths, thus maintaining diagnostic performance.
Implementation Method 1
an image signal acquisition device for acquiring image signals by imaging a subject body illuminated with light
Implementation Method 2
information related to an oxygen saturation level of hemoglobin in blood from an image signal obtained by imaging a subject body is acquired by use of light absorption characteristic of blood vessels
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
An oxygen saturation level of hemoglobin in blood is correctly acquired without lowering a frame rate. A subject body illuminated with white light W is imaged by a color CCD to obtain signals Bs1, Gs1 and Rs1. The subject body is illuminated with blue narrow band light BN of which absorption coefficient is changed by a change in the oxygen saturation level of the hemoglobin in blood, and imaged by the color CCD to obtain signals Bs2, Gs2 and Rs2. The signal Bs2 is divided by the signal Gs1 to determine a normalized signal Bs2/Gs1. The oxygen saturation level of blood vessels of the surface of body tissue is obtained according to the normalized signal Bs2/Gs1. The oxygen saturation level is visualized in a pseudo color, to form an oxygen saturation level image.