Endoscope Oxygen Saturation Image Reliability Correction
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Solution Overview
Problem
Current endoscope systems face challenges in accurately displaying oxygen saturation of hemoglobin due to inappropriate imaging conditions, such as excessive illumination, artificial objects, dirt on the mucosal surface, and varying spectral distribution characteristics, which lead to inaccurate differentiation between effective and ineffective regions.
Innovation Solution
The endoscope system incorporates an illuminating section, image signal obtaining section, signal ratio calculator, oxygen saturation calculator, reliability calculator, and image processing section to generate an oxygen saturation image by calculating signal ratios and reliability based on color difference signals, using a color tone information memory to correct color tone information and display accurate oxygen saturation data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a threshold value is set to distinguish effective and ineffective regions, then the differentiation between regions becomes clear, but the accuracy of oxygen saturation measurement deteriorates when the threshold is inappropriate
Solution Approach 1:
The patent changes the parameter for region differentiation from a fixed threshold value to a dynamic reliability value calculated based on multiple factors including pixel value, signal ratio, and optical absorption spectrum. This allows the system to adaptively determine region effectiveness while maintaining measurement accuracy through comprehensive parameter consideration.
Solution Approach 2:
The patent introduces a feedback mechanism where the reliability value is continuously calculated and updated based on the relationship between pixel values and optical absorption spectrum characteristics. This feedback loop allows the system to adjust the differentiation criteria dynamically, ensuring both clear region distinction and accurate oxygen saturation measurement.
2Illumination intensity
If excessive illumination light is applied to the portion being observed, then the image signal strength increases, but the oxygen saturation measurement becomes inaccurate
Solution Approach 1:
The patent replaces the mechanical approach of simply thresholding pixel values with an optical physics-based approach using the optical absorption spectrum of hemoglobin. By calculating reliability based on the relationship between pixel values and the known absorption characteristics of oxygenated and deoxygenated hemoglobin, the system can accurately measure oxygen saturation even under varying illumination conditions.
3Reliability
If the threshold value for ineffective region detection is lowered, then more regions are identified as ineffective, but the number of accurate oxygen saturation measurements decreases
Solution Approach 1:
The patent changes the detection parameter from a fixed threshold to a dynamically calculated reliability value that incorporates multiple factors including pixel value, signal ratio, and optical absorption spectrum. This comprehensive parameter approach allows the system to accurately identify truly ineffective regions (such as those with artificial objects or dirt) while preserving accurate measurements in regions that may have atypical pixel values but maintain valid optical characteristics.
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 enhances the accuracy of oxygen saturation display by determining reliability based on signal ratios and optical absorption spectrum, effectively distinguishing between effective and ineffective regions, and reflecting factors like dirt and uneven light distribution, resulting in improved diagnostic precision.
Implementation Method 1
The functional information is obtained based on light absorption property of blood vessels
Implementation Method 2
The first image signal is obtained from first reflection light including a wavelength range in which an absorption coefficient varies in accordance with oxygen saturation of hemoglobin in blood
Data Source
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AI summary
An image of a target portion is captured while first light beams are applied thereto. Thereby, a first image signal is obtained. The first light beams are in a wavelength range in which an absorption coefficient varies in accordance with a change in oxygen saturation of hemoglobin in blood. An image of the target portion is captured while second light beams in a broadband wavelength range are applied thereto. Thereby, second and third image signals are obtained. Oxygen saturation is calculated from the first to third image signals. Reliability of the oxygen saturation is calculated from one of the first to third image signals. Color difference signals each corresponding to the oxygen saturation is obtained from a color table (88a). Each of the color difference signals is corrected in accordance with the reliability. An oxygen saturation image is generated based on corrected color difference signals and displayed.