Endoscope Flush Detection for Rolling-Shutter Image Artifacts
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Solution Overview
Problem
The rolling shutter effect in CMOS sensors of endoscopes is exacerbated by rinsing operations, causing image distortions and bright reflections due to fast-moving rinsing fluids and liquids, which are perceived as apparatus malfunctions.
Innovation Solution
An endoscopic system that monitors pressure changes in the rinsing fluid system to detect flush events, switching illumination and capture modes accordingly, using modules like impulse detection and slope determination to analyze pressure signals for accurate flush detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a CMOS sensor operates in rolling shutter mode to enable continuous image capture, then productivity is improved, but image quality deteriorates due to rolling shutter effect when fast-moving objects are captured
Solution Approach 1:
The patent dynamically switches between rolling shutter mode and global shutter mode based on detected flush operations. During normal operation, rolling shutter mode maintains continuous capture capability. When a flush operation is detected (via pressure sensor or image analysis), the system temporarily switches to global shutter mode to eliminate rolling shutter artifacts caused by fast-moving fluid, then returns to rolling shutter mode afterward.
2Ease of operation
If a rinsing device provides high-speed fluid flow to effectively clean the light entrance surface, then cleaning effectiveness is improved, but image quality deteriorates due to rolling shutter effect and bright reflections
Solution Approach 1:
The system uses feedback from pressure sensors monitoring the rinsing fluid system to detect when flush operations are initiated. This feedback signal triggers the camera control unit to switch from rolling shutter mode to global shutter mode, coordinating the imaging mode change with the cleaning operation to minimize visual disturbances.
Solution Approach 2:
The patent introduces an intermediary detection mechanism (pressure sensor or image analysis algorithm) that mediates between the rinsing device operation and the camera capture mode. This intermediary detects the flush operation and coordinates the mode switch, ensuring that the high-speed cleaning function operates without degrading image quality.
3Illumination intensity
If bright illumination light is used to improve visibility, then illumination quality is improved, but image quality deteriorates due to bright reflections from liquid droplets
Solution Approach 1:
The system implements periodic switching of illumination intensity based on the operational phase. During detected flush operations, the illumination is temporarily reduced or turned off to prevent bright reflections from liquid droplets. Between flush operations, normal illumination levels are restored to maintain visibility. This periodic modulation of illumination coordinates with the flush detection and global shutter mode activation.
Data Source
AI summary
An endoscopic system and method for its operation are disclosed. The system comprises a light source, an endoscope with a distal light entrance surface, an image sensor capturing images through the light entrance surface and a rinsing device for providing a rinsing fluid flow for rinsing the light entrance surface, the method including the steps of receiving a sensor signal from a sensor detecting a user input starting a rinsing operation of the rinsing device, and, upon receipt of the sensor signal, changing an illumination mode of the light source from a first illumination mode to a second illumination mode and/or changing the video capture from a first video capture mode to a second video capture mode. The second illumination and/or video capture mask undesirable visual artifacts which can occur when collecting images with a rolling shutter sensors while performing a liquid flush of the light entrance surface.