Medical Observation Light Control for Balanced Fluorescence Imaging
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Solution Overview
Problem
In medical observation systems using CMOS rolling shutter type imaging elements, the imbalance in brightness between normal light and fluorescence images occurs due to mismatched light emission periods of normal and excitation lights, leading to unsuitable image generation.
Innovation Solution
A medical observation system with a light source controller that adjusts the light emission periods of first and second lights to maintain a predetermined ratio of energy exposure in imaging devices, ensuring balanced brightness between normal and fluorescence images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the light emission period of excitation light is changed at the same rate as the change in the light emission period of normal light, then the control operation is simplified, but the brightness balance between normal light image and fluorescence image is deteriorated
Solution Approach 1:
The patent changes the control parameter from uniform light emission period adjustment to separate adjustment based on exposure area calculations. The light source controller calculates the exposure area for each light type and adjusts their emission periods independently to maintain a predetermined exposure area ratio, rather than changing both at the same rate.
Solution Approach 2:
The system implements feedback control by calculating the exposure area for each light type based on the imaging element's characteristics and adjusting the light emission periods to maintain the desired exposure area ratio. This closed-loop control ensures the brightness balance is maintained despite changes in imaging parameters.
2Illumination intensity
If excitation light is emitted outside the entire line exposure period, then the fluorescence image brightness is improved, but the relationship between normal light and fluorescence image brightness becomes unbalanced
Solution Approach 1:
The patent makes the light emission periods dynamic and adjustable based on the imaging element's exposure characteristics. The system adapts the emission timing of both normal light and excitation light to match the imaging element's exposure period, allowing flexible adjustment while maintaining the predetermined exposure area ratio between the two light types.
3Measurement precision
If PWM control is used to adjust light emission periods, then the light intensity control precision is improved, but the complexity of light source control increases
Solution Approach 1:
The patent introduces a light source controller as an intermediary device that manages the PWM control of multiple light sources. This controller calculates the appropriate exposure areas and generates the corresponding PWM signals, simplifying the overall system architecture while maintaining precise control through standardized PWM modulation.
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 generates images with favorable brightness balance between normal and fluorescence images, addressing the imbalance issue and producing suitable observation images.
Implementation Method 1
an imaging device that images return light of first light and second light from an observation target
Implementation Method 2
the fluorescence image is an image obtained by irradiating the observation target with excitation light from the light source device and imaging the fluorescence from the observation target excited by the excitation light
Data Source
AI summary
A medical observation system includes: a light source device configured to emit first light and second light to an observation target; an imaging device configured to image return light of the first light and the second light from the observation target, and change number of horizontal lines to be simultaneously exposed by at least one of the return light of the first light and the return light of the second light; and a light source controller configured to adjust light emission periods of the first light and the second light such that energy of light obtained by exposing the return light of the first light in the imaging device and energy of light obtained by exposing the return light of the second light in the imaging device have a predetermined ratio.