Endoscope Spectral Correction for Accurate Oxygen Saturation
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Solution Overview
Problem
Existing endoscope systems face challenges in accurately calculating oxygen saturation due to individual differences in light source units and endoscopes, which are not adequately addressed by conventional white balance correction processing.
Innovation Solution
The endoscope system employs a combination of semiconductor light sources with specific wavelength ranges, first correction parameters to correct spectral characteristics, and white balance correction data to calculate oxygen saturation accurately, using a processor to adjust for individual differences in light sources and endoscopes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If white balance correction processing is performed to correct differences in signal ratio, then individual differences in light source units are partially corrected, but oxygen saturation calculation accuracy is insufficient because white balance correction only corrects white portions and not other color portions
Solution Approach 1:
The patent changes the correction parameters from white balance correction values (which only correct white portions) to spectral characteristic correction values specific to each semiconductor light source wavelength range. By storing and applying correction values for each wavelength range (blue, green, red, yellow-green), the system achieves comprehensive correction across all color portions, not just white portions, thereby improving oxygen saturation calculation accuracy.
Solution Approach 2:
The patent segments the correction process by wavelength ranges corresponding to each semiconductor light source (blue, green, red, yellow-green). Instead of applying a single white balance correction to all colors, the system performs separate correction for each wavelength range using stored spectral characteristic correction values. This segmented approach ensures that each color portion is corrected appropriately, resolving the limitation of conventional white balance correction.
2Adaptability or versatility
If multiple semiconductor light sources with different wavelength ranges are used to obtain spectral images, then oxygen saturation observation capability is improved, but individual differences in spectral characteristics of light source units cause signal ratio variations
Solution Approach 1:
The patent performs preliminary correction by storing spectral characteristic correction values for each semiconductor light source before oxygen saturation calculation. During actual measurement, these pre-stored correction values are applied to the spectral images to compensate for individual differences in light source units. This preliminary correction action ensures signal ratio consistency across different light source units while maintaining the multi-wavelength observation capability.
Solution Approach 2:
The system incorporates feedback by using the known spectral characteristics of each semiconductor light source to generate correction values that are applied back to the captured images. This feedback mechanism compensates for variations in actual light output from each wavelength range, ensuring that the signal ratios accurately reflect tissue properties rather than light source differences, thereby maintaining measurement precision across multiple light sources.
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 calculation of oxygen saturation by correcting for variations in spectral characteristics and signal ratios, ensuring accurate oxygen saturation measurements despite variations in light source units and endoscopes.
Implementation Method 1
a light source device that includes a plurality of semiconductor light sources emitting illumination light having a plurality of wavelength ranges
Implementation Method 2
an endoscope that obtains a plurality of spectral images from image pickup of an object to be observed illuminated on the basis of the illumination light
Implementation Method 3
an image control processor that calculates oxygen saturation of the object to be observed on the basis of the plurality of spectral images, the first correction parameters, and the white balance correction data
Implementation Method 4
the oxygen saturation of the object to be observed is calculated on the basis of a plurality of spectral images, which are obtained in a case where an affected area is irradiated with illumination light for oxygen saturation observation of which the light absorption coefficient is changed depending on oxygen saturation
Data Source
AI summary
An endoscope obtains a plurality of spectral images from the image pickup of an object to be observed illuminated on the basis of illumination light. A special processing section calculates oxygen saturation of the object to be observed on the basis of the plurality of spectral images, first correction parameters that are used to correct differences in the spectral characteristics of the respective semiconductor light sources, and white balance correction data.