Endoscope Imaging Pixel Row Resetting for Luminance and S/N Ratio
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Solution Overview
Problem
In endoscope systems, the special observation mode experiences decreased luminance and signal-to-noise (S/N) ratio due to shortened exposure times, leading to lower quality normal observation images compared to normal observation mode.
Innovation Solution
Implementing a control unit that manages the imaging element to perform specific resetting and reading schemes, including a second imaging scheme where some pixel rows are reset en bloc after first illumination and all pixel rows are read after second illumination, allowing for improved luminance and S/N ratio in special observation mode images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If exposure time is shortened to maintain frame rate in special observation mode, then frame rate is maintained, but luminance and S/N ratio of normal observation images decrease
Solution Approach 1:
The imaging element is divided into multiple pixel rows that are reset and read out in different sequences. Some pixel rows are reset before first illumination and read after second illumination, while other pixel rows are reset after first illumination and read after second illumination. This segmentation allows different regions to capture different illumination phases independently, enabling both long effective exposure for luminance and maintained frame rate.
Solution Approach 2:
Certain pixel rows are reset in advance before the first illumination phase begins. This preliminary resetting ensures that these pixel rows are ready to accumulate photons during the first illumination phase, maximizing the effective exposure time for normal observation images without delaying the overall frame rate.
2Reliability
If turn-off period is provided during illumination switching, then illumination switching is completed, but frame rate decreases
Solution Approach 1:
The system eliminates idle turn-off periods by continuously illuminating the specimen with alternating first and second illumination lights while the imaging element continuously reads out signals from different pixel rows. This continuous operation removes wasted time between illumination phases, maintaining frame rate while ensuring complete illumination switching cycles are performed for accurate special observation imaging.
3Device complexity
If sequential pixel row resetting and reading is performed, then device complexity is reduced, but normal observation image quality decreases in special observation mode
Solution Approach 1:
The system dynamically changes the reset and readout sequences for different pixel rows based on the illumination phase. Pixel rows are selectively reset and read out at different times depending on whether they need to capture first illumination (normal observation) or second illumination (special observation) information. This dynamic control enables high-quality imaging in both modes without requiring complex hardware modifications.
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 enhances the luminance and S/N ratio of normal observation images in special observation mode without decreasing frame rate, by optimizing the exposure and reading processes for both illumination lights.
Implementation Method 1
a CMOS type imaging element is used... in which a rolling shutter scheme in which resetting and signal reading are performed sequentially pixel row by pixel row for a plurality of pixel rows configured in the imaging unit is adopted
Data Source
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AI summary
Provided are an endoscope system capable of improving luminance and an S/N ratio of a normal observation image that is obtained in a special observation mode, a processor device of the endoscope system, and a method of operating the endoscope system. In a special observation mode, after first illumination light is radiated, some of a plurality of pixel rows of an imaging element (39) are reset en bloc. Illumination light is switched from the first illumination light to second illumination light, the second illumination light is radiated, and then, a turned-off state is reached. During this turn-off period, signal reading is sequentially performed from all pixel rows. An image processing unit (44) generates a normal observation image on the basis of a first imaging signal read from the pixel row exposed by the first and second illumination light without being subjected to resetting. Further, the image processing unit (44) generates an oxygen saturation image on the basis of a second imaging signal read from the pixel row subjected to the resetting and exposed by only the second illumination light, and the first imaging signal.