Endoscope Light Source Wavelength Shift Compensation

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Solution Overview

Problem

Conventional endoscope systems using semiconductor light sources for narrow-band light observation can result in images with different color tones due to shifts in the center wavelength of emitted light, affecting the visualization of blood vessels and tissue contours.

Innovation Solution

An endoscope apparatus that generates and processes multiple narrow-band lights within specific wavelength ranges, including red, blue, and green ranges, to maintain a predetermined brightness ratio and adjust for light source variations, ensuring consistent color tone visualization of hemoglobin-containing regions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If semiconductor light sources (LED/LD) are used to generate narrow band light, then the light source can be compact and efficient, but the center wavelength shifts cause color tone variations in the captured images

Engineering Contradiction:

Improvelight generation efficiencyVSAvoidcolor tone accuracy

Core Design Contradiction:

Use of energy by moving objectVSMeasurement precision

Solution Approach 1:

The system detects the actual center wavelength of the semiconductor light source and uses this detection result to adjust the imaging conditions (exposure time, gain, filtration) to compensate for wavelength shifts, thereby maintaining accurate color tone representation despite using efficient semiconductor light sources

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system changes imaging parameters (exposure time, amplification, optical filtration) based on the detected light source wavelength characteristics to compensate for wavelength shifts and maintain consistent color tone across different operating conditions

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If multiple narrow band lights are used to visualize blood vessels at different depths, then the observation capability is improved, but the system complexity increases

Engineering Contradiction:

Improveobservation capabilityVSAvoidsystem complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The semiconductor light source is designed to emit multiple narrow band wavelengths (e.g., 600nm and 630nm) from a single device, enabling the system to visualize blood vessels at different depths using one light source rather than requiring multiple separate light sources

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system combines multiple narrow band light wavelengths from a single semiconductor light source to achieve multi-depth blood vessel visualization, merging the functionality of what would otherwise require separate light sources into one integrated device

Inventive Principle:

Principle #5Merging (Combining)

3Ease of manufacture

If the center wavelength of narrow band light shifts, then the light source can adapt to manufacturing variations, but the image color tone becomes inconsistent

Engineering Contradiction:

Improvelight source manufacturing toleranceVSAvoidimage color consistency

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The system includes a wavelength detection mechanism that measures the actual center wavelength of the semiconductor light source and uses this feedback to adjust imaging parameters, compensating for manufacturing variations and maintaining consistent color tone in captured images

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system dynamically adjusts imaging parameters (exposure time, gain, optical filtration) based on the detected wavelength shift, allowing the system to accommodate manufacturing tolerances in light source production while maintaining precise color tone representation

Inventive Principle:

Principle #35Parameter changes

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 provides accurate and consistent visualization of blood vessels and tissue contours by maintaining a predetermined brightness ratio of narrow-band light images, reducing color tone variations and improving observation accuracy.

Implementation Method 1

a semiconductor light source such as an LED or an LD (laser diode) has been generally used as a light source configured to generate narrow band light

Methodology Applied

Scientific EffectLight emission from semiconductor: Light Emitting Diode

Implementation Method 2

irradiating a living tissue with narrow-band light having a center wavelength (wavelength band) set depending on a light absorption characteristic of hemoglobin

Methodology Applied

Scientific EffectLight absorption by hemoglobin: Absorption (EM radiation)

Data Source

PatentUS11464393B2Endoscope apparatus and method of operating endoscope apparatus

Publication Date: 2022.10.11 OLYMPUS CORPORATION(JP)

AI summary

An endoscope apparatus includes a light source apparatus, an image processing circuit configured to subject a first image or a second image obtained by irradiating first or second narrow band light to predetermined image processing and output the image, and a control circuit configured to perform control to acquire signal intensity information about a signal intensity of the image pickup signal outputted from the image pickup device in response to irradiation with the first narrow band light based on a current operation state of a light source configured to generate first narrow band light and further maintain a ratio of respective brightnesses of the first image and the second image used for generating the observation image to be a predetermined ratio based on the signal intensity information.