Imaging Apparatus Illumination Synchronization CMOS
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Solution Overview
Problem
Endoscope systems face challenges in capturing images under multiple illumination types without mixing different illumination effects, especially when using CMOS image sensors with electronic focal-plane shutters, which can result in time lag and mixed illumination in image data.
Innovation Solution
The system employs a light source controller to sequentially emit multiple illumination types for at least two frame periods, synchronizing with the exposure period of the sensor, and the control unit acquires image data only from the second frame period, excluding data from the first frame period to ensure images are captured under a single type of illumination, thereby avoiding mixed illumination effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple types of illumination lights are sequentially switched to capture images under different illumination conditions, then the versatility and diagnostic capability are improved, but the image data may become mixed with different illumination effects and time lag artifacts deteriorate
Solution Approach 1:
The image data from the sensor is divided into multiple pieces corresponding to different horizontal lines, and each piece is associated with specific illumination timing information. This segmentation allows the system to separate and identify which parts of the image data were captured under which illumination conditions, preventing mixing of different illumination effects while maintaining the ability to switch between multiple illumination types for enhanced diagnostic capability
Solution Approach 2:
The system preliminarily tags each piece of image data with timing information indicating which illumination light was active during capture. By preparing this timing information in advance and using it to guide the image processing, the system ensures that only image data captured under the intended illumination conditions is processed together, eliminating time lag artifacts and maintaining image data purity while preserving versatility
2Device complexity
If the sensor reads pixel information sequentially line by line during illumination switching, then the device complexity is reduced, but time lag causes mixed illumination effects in the captured image data
Solution Approach 1:
The system dynamically adjusts the illumination switching timing to coincide with the sequential line-by-line reading process of the sensor. By synchronizing the illumination changes with the progressive scan timing, the system ensures that each horizontal line is captured under a specific illumination condition without requiring complex mechanical shutters or additional hardware, thus maintaining simple device structure while achieving accurate image capture without mixed illumination effects
Solution Approach 2:
The timing information indicating which illumination light was active during each line reading is prepared in advance and stored alongside the corresponding image data. This preliminary preparation of timing metadata allows the system to accurately associate each pixel row with its illumination condition, ensuring image capture accuracy without adding complex hardware components
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 allows for seamless operation during multiple illumination switching, ensuring adequate sensitivity and consistent image capture under each illumination type, even with CMOS-type imaging elements, by selecting appropriate image acquisition based on switched illumination.
Implementation Method 1
a plurality of pixels that each generates, upon receipt of light, an electrical signal through photoelectric conversion
Data Source
AI summary
Imaging apparatus performs controlling to read pixel information from pixels belonging to target area by each frame. One frame period is period from when an exposure period for exposing pixels on a horizontal line that is to be read first from among horizontal lines belonging to the target area of a sensor is started and until when reading of the pixel information generated by each of the pixels on the horizontal line is completed. The imaging apparatus sequentially emits, by each illumination period of a length corresponding to at least two frame periods, illumination lights in synchronization with start of the exposure period. The imaging apparatus performs a predetermined controlling by performing controlling to exclude, from predetermined processing target, image data corresponding to the pixel information read during first frame period of the illumination period, while by acquiring image data corresponding to the pixel information read during other frame period.