Endoscope Light Source Control for Oxygen Saturation Accuracy
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Solution Overview
Problem
Endoscope systems using semiconductor light sources face challenges in accurately calculating oxygen saturation due to response delays and overshoots when turning illumination light on and off, leading to deviations in light emitting quantity ratios between frames, which affect image signal ratios and measurement accuracy.
Innovation Solution
An endoscope system with multiple light sources emitting different wavelengths, equipped with photodetectors to monitor light emitting quantities and a control unit that adjusts light emitting quantities and timing to maintain constant image signal ratios by using feedback control and error calculation to correct for overshoots and delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If semiconductor light sources are used to enable energy conservation and narrow band imaging, then energy efficiency and imaging functionality are improved, but response delays and overshoots occur when turning illumination light on and off, causing deviations in light emitting quantity ratios
Solution Approach 1:
The system performs preliminary actions by capturing reference images at multiple gain values before actual measurement. These reference images are used to calculate correction values that compensate for the semiconductor light source's response delays and overshoots, ensuring accurate light emitting quantity ratios during oxygen saturation measurement.
Solution Approach 2:
The system implements feedback control by using photodetectors to monitor the actual light emitting quantities and comparing them with target values. Based on this feedback, the control unit adjusts the drive signals to minimize deviations caused by response delays and overshoots, maintaining reliable light emitting quantity ratios.
2Adaptability or versatility
If the illumination light is completely turned off and on for multi-frame observation, then oxygen saturation measurement capability is improved, but response delays cause deviations in image signal ratios between frames
Solution Approach 1:
The system captures reference images at multiple gain values before actual oxygen saturation measurement. These preliminary reference images enable the calculation of correction values that compensate for response delays, ensuring accurate image signal ratios when the illumination light is turned on and off for multi-frame observation.
Solution Approach 2:
The system changes the gain parameter of the semiconductor light source during reference image capture to establish a relationship between gain values and light emitting quantities. This parameter variation enables the calculation of correction values that maintain measurement precision despite response delays during illumination switching.
3Adaptability or versatility
If multiple light sources with different wavelengths are used for multi-frame observation, then oxygen saturation imaging capability is improved, but overshoots in light emitting quantity affect image signal ratio constancy
Solution Approach 1:
The system performs preliminary capture of reference images for each light source at multiple gain values before actual oxygen saturation imaging. These reference images are used to calculate correction values that compensate for overshoots, ensuring that image signal ratios remain constant across multiple frames even when multiple light sources with different wavelengths are used.
Solution Approach 2:
The system uses photodetectors to monitor light emitting quantities from multiple light sources and implements feedback control. Based on feedback from actual measurements compared with reference values, the control unit adjusts drive signals to compensate for overshoots, maintaining stable image signal ratios across frames for accurate oxygen saturation imaging.
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 ensures accurate and precise control of light emitting quantities and timing, maintaining constant image signal ratios across frames, thereby enhancing the accuracy of oxygen saturation calculations and image quality.
Implementation Method 1
a photodetector which is provided in each of the plurality of light sources and which receives a part of light from the plurality of light sources and obtains information on a light emitting quantity of the plurality of light sources
Data Source
AI summary
An endoscope system includes a plurality of light sources which emits light having different wavelengths, a photodetector which is provided in each of the plurality of light sources, and which receives a part of the light of the plurality of light sources and obtains information on a light emitting quantity of the plurality of light sources, an image acquisition unit that acquires an image to be observed for each illumination light using at least first illumination light and second illumination light, composed of the light emitted from at least one of the plurality of light sources, and a control unit that makes a mutual image signal ratio constant in the plurality of images acquired by the image acquisition unit.