Endoscope Color Correction via LED Feedback Control
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Solution Overview
Problem
Existing endoscope systems face challenges in maintaining consistent color tone due to wavelength shifts in semiconductor light sources, particularly red LEDs, which can lead to incorrect diagnoses, such as confusing crystal violet with bleeding tissue, as the peak wavelength shifts with light intensity variations.
Innovation Solution
An endoscope system that includes a semiconductor light source apparatus with a measurement sensor to adjust the drive value of the light source, a color converter that performs matrix operations to correct color images based on the drive value, and a table memory to store and retrieve matrix coefficients for precise color conversion, ensuring consistent color tone across varying light intensities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the light intensity of the semiconductor light source is increased, then the illumination brightness is improved, but the peak wavelength shifts to the long wavelength side causing color tone change
Solution Approach 1:
The patent employs a feedback mechanism where a light receiver detects the light amount from the semiconductor light source, and the processing apparatus adjusts the drive current based on detection results to maintain constant color temperature. This closed-loop control compensates for wavelength shifts that occur when light intensity changes, allowing bright illumination while maintaining accurate color tone.
Solution Approach 2:
The patent changes the drive current parameter of the semiconductor light source dynamically. By adjusting the drive current based on detected light amount, the system compensates for wavelength shifts. Additionally, the patent uses multiple semiconductor light sources with different characteristics (different peak wavelengths) and switches between them or combines their output to maintain optimal color tone across various illumination levels.
2Power
If the drive current of the semiconductor light source is increased, then the light output is improved, but the wavelength shift causes imaging quality degradation
Solution Approach 1:
The processing apparatus continuously monitors the light amount from each semiconductor light source using light receivers and adjusts drive currents in real-time based on detection results. This feedback control ensures that even at high power output, the wavelength remains stable and imaging quality is maintained.
Solution Approach 2:
The patent divides the illumination function into multiple semiconductor light sources with different characteristics (different peak wavelengths and spectral properties). By segmenting the light source system, the patent can selectively activate or adjust individual sources to maintain optimal wavelength and color tone even when high total light output is required.
3Adaptability or versatility
If multiple color semiconductor light sources are used to achieve white light, then the illumination coverage is improved, but the ratio control becomes complex due to individual light amount variations
Solution Approach 1:
The patent uses light receivers to detect the light amount from each semiconductor light source individually. The processing apparatus uses these detection results to automatically adjust drive currents and maintain the correct intensity ratios between different color sources. This feedback mechanism simplifies the control complexity by automating the ratio adjustment process.
Solution Approach 2:
The system performs self-adjustment by using the detected light amount information to automatically control the drive currents of individual semiconductor light sources. This self-service mechanism eliminates the need for complex manual calibration or external control systems, as the system automatically maintains optimal color mixing ratios.
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 effectively corrects color tone changes caused by wavelength shifts and aging degradation, maintaining accurate imaging quality by adjusting the light source drive values and matrix coefficients, thereby preventing misdiagnoses.
Implementation Method 1
a measurement sensor measures a light amount of the light
Implementation Method 2
A color converter performs color conversion of the first color image signal into a second color image signal
Data Source
AI summary
A V-LED, B-LED, G-LED and R-LED for an endoscope are all driven to apply normal light to an object of interest in a body. An image sensor images the illuminated object and outputs an RGB image signal. A measurement sensor measures a light amount of red light from the R-LED. A light source controller acquires a current value for the R-LED according to a light amount signal from the measurement sensor and a target light amount signal for the R-LED. A normal color converter and the R-LED receive a current of the current value. Each LUT_Mij in the normal color converter is referred to for outputting a matrix coefficient according to the current value of the R-LED. The RGB image signal is converted into a processed image signal by matrix operation according to the matrix coefficient.