Endoscope CMOS Image Sensor Droplet Edging Mitigation
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Solution Overview
Problem
Endoscopes equipped with CMOS image pickup elements using the rolling shutter method exhibit an 'edging phenomenon' where unnatural edges appear in droplet images due to differences in exposure timings, leading to potential misinterpretation of image quality.
Innovation Solution
The endoscope apparatus includes detection and exposure control mechanisms to identify and mitigate the edging phenomenon by lengthening exposure times for scan lines when specific conditions are detected, such as fluid operations, and employing pseudo-global shutter methods to prevent unnatural edge formation in droplet images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a rolling shutter method is used for exposure control in CMOS image pickup elements, then the device complexity is reduced and manufacturing is easier, but an edging phenomenon occurs where unnatural edges appear in droplet images due to differences in exposure timings for each scan line
Solution Approach 1:
The patent dynamically adjusts the exposure time of scan lines based on detected droplet positions. When droplets are detected, the exposure time for affected scan lines is extended to ensure complete capture of droplet images, preventing the edging phenomenon while maintaining the rolling shutter method's manufacturing advantages
Solution Approach 2:
The patent changes the exposure time parameter dynamically based on detection results. By extending the exposure time for scan lines where droplets are detected, the system eliminates unnatural edges in droplet images while preserving the overall rolling shutter operation and its manufacturing benefits
2Manufacturing precision
If the exposure time is extended for scan lines where droplets are detected, then the edging phenomenon is prevented and image quality improves, but the productivity decreases due to longer exposure times
Solution Approach 1:
The patent applies local quality by extending exposure time only for specific scan lines where droplets are detected, rather than extending exposure time for the entire frame. This localized adjustment improves image quality for affected areas while minimizing the impact on overall productivity
Solution Approach 2:
The patent uses partial action by applying extended exposure time only to the extent necessary - specifically for scan lines containing droplets - rather than applying it universally. This partial application achieves the needed image quality improvement while limiting productivity loss
3Manufacturing precision
If a pseudo-global shutter method is used during fluid operations, then the edging phenomenon is completely eliminated, but the device complexity increases and the ease of operation decreases
Solution Approach 1:
The patent dynamically switches between rolling shutter and pseudo-global shutter methods based on operational context. During fluid operations when droplets are likely to appear, it uses pseudo-global shutter to eliminate edging phenomena; during normal operations, it uses the simpler rolling shutter method, thus maintaining ease of operation while achieving high image quality when needed
4Manufacturing precision
If the exposure timing is synchronized across all scan lines simultaneously, then the edging phenomenon is prevented, but the device complexity increases due to the need for pseudo-global shutter implementation
Solution Approach 1:
The patent implements a dynamic switching mechanism that uses pseudo-global shutter only when necessary (during fluid operations with detected droplets) while maintaining rolling shutter for normal operations. This reduces overall device complexity compared to always using pseudo-global shutter, while still achieving edging phenomenon prevention when needed
Data Source
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AI summary
This invention provides an endoscope apparatus that can make an edging phenomenon in which an unnatural edge arises in a droplet image that appears in an observation video of an endoscope not visually recognizable by an observer, and an image pickup control method of the endoscope apparatus. By performing edging phenomenon detection processing and determination processing, a processor apparatus determines whether or not an edging phenomenon in which an edge in a horizontal direction arises in an image of a scattering droplet occurs in a frame image that was imaged by a CMOS type image pickup element of an endoscope (S10, S 12). If the edging phenomenon is occurring, the processor apparatus executes edging phenomenon mitigation processing to mitigate the effects of the edging phenomenon (S 14). As the edging phenomenon mitigation processing, an exposure time of the image pickup element is lengthened compared to a time of normal imaging to mitigate the effects of the edging phenomenon.