Endoscope Processor Oxygen Saturation Image Merging

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Solution Overview

Problem

Existing endoscope systems struggle to accurately display oxygen saturation levels independently of blood volume, making it difficult to diagnose changes in mucosal properties due to the dependence on red hue gradation for both oxygen saturation and blood volume information.

Innovation Solution

A processor for an endoscope system that calculates oxygen saturation levels using a combination of first and second image signals captured under different illumination lights, adjusting pixel levels based on calculated oxygen saturation levels to produce an oxygen saturation image that merges this information into an ordinary image, while maintaining the natural appearance of the subject.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If false-color processing is applied to display oxygen saturation levels, then oxygen saturation information becomes visible, but the image loses natural body colors making it difficult to diagnose mucosal property changes

Engineering Contradiction:
Improveoxygen saturation information visibilityVSAvoiddiagnostic capability for mucosal properties
Core Design Contradiction:
Loss of informationVSEase of manufacture

Solution Approach 1:

The patent merges oxygen saturation information with the ordinary color image by adjusting the color tone of the original image based on calculated oxygen saturation levels, rather than replacing the image with a completely false-color representation. This combines the advantages of both natural color visualization and oxygen saturation information display.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent applies different color adjustments to different regions of the image based on local oxygen saturation levels. Areas with abnormal oxygen saturation receive color tone modifications while areas with normal saturation maintain their natural appearance, creating a spatially varying processing effect.

Inventive Principle:
Principle #3Local quality

2Loss of information

If red hue gradation is used to display oxygen saturation levels, then oxygen saturation information is visualized, but blood volume information interferes making it hard to discriminate oxygen saturation magnitude

Engineering Contradiction:
Improveoxygen saturation visualizationVSAvoidoxygen saturation measurement accuracy
Core Design Contradiction:
Loss of informationVSMeasurement precision

Solution Approach 1:

The patent extracts oxygen saturation information from the image signals and uses it as a separate control parameter for color tone adjustment. By separating the oxygen saturation calculation from the blood volume information and using only the oxygen saturation data for color modulation, the interference from blood volume is eliminated.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent performs preliminary calculation of oxygen saturation levels from the captured image signals before applying color adjustments. This pre-calculation step allows the system to determine the appropriate color tone modification based solely on oxygen saturation, preventing subsequent confusion with blood volume effects.

Inventive Principle:
Principle #10Preliminary action

3Loss of information

If narrowband light is used for illumination to make blood vessels conspicuous, then vascular structures become visible, but the image loses natural color representation

Engineering Contradiction:
Improvevascular structure visibilityVSAvoidnatural color reproduction
Core Design Contradiction:
Loss of informationVSEase of manufacture

Solution Approach 1:

The patent merges the advantages of narrowband illumination (enhanced vascular visibility) with natural color reproduction by capturing images under narrowband light and then restoring natural colors through processing while preserving the enhanced vascular contrast information.

Inventive Principle:
Principle #5Merging (Combining)

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

Enables the production of an oxygen saturation image that accurately reflects oxygen saturation levels independently of blood volume, facilitating better medical diagnosis by displaying normal oxygen saturation areas in natural body colors and abnormal areas in distinct colors.

Implementation Method 1

an imaging device for receiving the light reflected from the test subject body to produce first and second image signals

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 2

calculating means for calculating blood hemoglobin information including oxygen saturation levels on the basis of the first and second image signals

Methodology Applied
Scientific EffectAbsorption spectroscopy: Absorption Spectroscopy

Data Source

PatentEP2891450B1Endoscope system and processor of endoscope system
Publication Date: 2018.12.05 FUJIFILM CORP
  • EP2891450B1 patent drawingFigure 1
  • EP2891450B1 patent drawingFigure 2
  • EP2891450B1 patent drawingFigure 3~4

AI summary

First illumination light (BN) of a first wavelength range, in which light absorption coefficient of blood hemoglobin varies with oxygen saturation thereof, is projected into a test subject body, to capture a first image signal from the first illumination light as reflected from inside the test subject body. Then second illumination light (BB) of a second wavelength range different from the first wavelength range is projected into the test subject body, to capture a second image signal from the second illumination light as reflected from inside the test subject body. A subject image of the test subject is produced from the second image signal. Oxygen saturation levels of the test subject are calculated using the first and second image signals. According to the calculated oxygen saturation levels, color properties of the subject image are changed to produce an oxygen saturation image.