Endoscope Color Reproducibility Using Multi-Wavelength Laser Illumination
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Solution Overview
Problem
Current endoscope technologies face challenges in achieving high color reproducibility due to the lack of information about light wavelengths not included in the laser light used for illumination, particularly with subjects that have varying reflectance across different wavelengths, leading to inaccurate color representation.
Innovation Solution
The endoscope apparatus employs a combination of first and second wavelength narrow-band lights with peak wavelengths of 405 nm and 660 nm, respectively, which are alternately radiated to the subject, and an image processing circuit that decides the subject type and constructs a display image signal based on these wavelengths, using stored subject types and their spectral reflectance information to enhance color reproducibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If laser light with specific wavelengths (e.g., 636 nm) is used for illumination, then the efficiency of guiding laser light to the diffusion plate is improved, but color reproducibility deteriorates due to lack of information about light with wavelengths not included in the laser light
Solution Approach 1:
The illumination light is divided into multiple discrete wavelength components (e.g., 405 nm, 530 nm, 660 nm narrow-band lights). Each wavelength is separately controlled and can be independently adjusted, allowing the system to segment the spectral information to accurately represent different color characteristics of the subject while maintaining efficient laser light guidance through the optical fiber and diffusion plate.
2Use of energy by moving object
If a three-primary-color (white-color) laser light source is used, then the efficiency of guiding laser light to the diffusion plate is increased, but color reproducibility deteriorates when there is a difference in reflectance of the living body between red laser light and light with wavelengths close thereto
Solution Approach 1:
Instead of using a single white-color laser source, the system employs multiple discrete wavelength light sources (405 nm, 530 nm, 660 nm) with different spectral characteristics. Each wavelength can be independently controlled to match the local reflectance characteristics of different subject areas, allowing accurate color reproduction while maintaining efficient light guidance through the shared optical fiber and diffusion plate structure.
3Illumination intensity
If laser light is used for illumination, then the brightness and efficiency are improved, but information about light with wavelengths not included in the laser light is lost
Solution Approach 1:
The system uses a multi-wavelength laser illumination system where multiple discrete wavelength lights (405 nm, 530 nm, 660 nm) are combined to provide both high brightness and comprehensive spectral information. The imaging device captures information from all these wavelengths simultaneously, allowing the system to universally represent various color characteristics of the subject while maintaining high illumination efficiency through the laser light sources and optical fiber transmission.
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 allows for accurate specification of subject types and brightness, resulting in high color reproducibility images even with low color rendering illumination, effectively addressing the limitations of existing technologies by utilizing discrete narrow-band light.
Implementation Method 1
an imaging device that acquires image light from the subject with pixels to generate an acquisition image signal
Implementation Method 2
an illumination apparatus that applies first wavelength narrow-band light and second wavelength narrow-band light that have peak wavelengths different from each other to a subject
Data Source
AI summary
An endoscope apparatus includes an illumination apparatus that applies first and second narrow-band light having different peak wavelengths to a subject, an imaging device that acquires image light from the subject with pixels to generate an acquisition image signal, and an image processing circuit. The image processing circuit includes a storage that has stored assumed subject types including information about a wavelength range of assumed subjects, and a subject type decision circuit that decides an assumed subject type for part of the pixels based on a first image signal about the first narrow-band light, a second image signal about the second narrow-band light, and the assumed subject types. The image processing circuit constructs a display image signal based on the acquisition image signal and decided assumed subject type.