Electronic Endoscope Rotating Filter Brightness Control
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Solution Overview
Problem
Electronic endoscopes face challenges in displaying normal and spectral images with proper brightness due to reduced light intensity through band-pass filters, leading to insufficient brightness in normal observation images and difficulties in auto-brightness adjustments.
Innovation Solution
An electronic endoscope with a rotating filter system that includes optical band-pass and Neutral Density filters, synchronized to alternate light-path intervals, and an image generator with a brightness adjuster to increase spectral image brightness, while adjusting the ND filter transmittance to match the brightness of the spectral image, ensuring both images are displayed at the same brightness level.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a band-pass filter is used to display spectral images, then spectral image quality is improved, but the amount of light passing through decreases, causing normal observation image brightness to be insufficient
Solution Approach 1:
The rotary filter is segmented into multiple filter sections arranged circumferentially, including band-pass filters for spectral imaging and ND filters for normal imaging. Each section serves a specific function, allowing the system to switch between spectral and normal observation modes by rotating to the appropriate filter section.
Solution Approach 2:
The rotary filter rotates periodically to alternate between band-pass filters and ND filters in the light path. This periodic action allows the system to switch between spectral image acquisition and normal image acquisition with appropriate brightness control for each mode.
2Illumination intensity
If the transmittance of the ND filter is set to match the spectral image brightness, then both images can be displayed at the same brightness level, but the auto-brightness process becomes difficult because the aperture must be opened wider than usual
Solution Approach 1:
The system employs an auto-brightness adjustment mechanism that uses feedback from the detected image brightness to automatically control the aperture opening. When the ND filter is in the light path, the feedback loop detects the reduced brightness and automatically opens the aperture wider to compensate, eliminating the need for manual adjustment and simplifying operation.
3Illumination intensity
If the ND filter reduces light intensity to match spectral image brightness, then brightness uniformity between normal and spectral images is improved, but the amount of light available for normal observation decreases
Solution Approach 1:
The system dynamically adjusts the aperture opening based on which filter is currently in the light path. When the ND filter is active for normal observation, the aperture automatically opens wider to compensate for the light reduction, ensuring sufficient light quantity while maintaining brightness uniformity across different imaging modes.
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 solution allows for simultaneous display of normal and spectral images with proper brightness, enhancing diagnostic capabilities by maintaining image quality and enabling precise auto-brightness adjustments.
Implementation Method 1
a rotary filter in which an ND (Neutral Density) filter and an optical band-pass filter are formed circumferentially
Implementation Method 2
The ND filter reduces the intensity or amount of all wavelengths of visible light equally when the visible light passes through the ND filter
Data Source
AI summary
An electronic endoscope has a light source configured to emit normal light toward an object and a rotating filter configured to be positioned in the path of light that passes from the light source to an image sensor. The rotating filter has an optical band-pass filter and a ND filter. The electronic endoscope has further a rotation controller that synchronizes a light-path traverse-interval of the band-pass filter and a light-path traverse-interval of the ND filter with a field/frame interval; and an image generator that generates a normal image from broadband image-pixel signals and generates a spectral image from specific-band image-pixel signals. The image generator has a brightness adjuster that increases a brightness level of the spectral image. Then, the ND filter reduces an amount of light emitted from the light source to an amount of light that corresponds to an increased brightness of the spectral image.