Endoscope Pixel Correction for Blinking Defects
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Solution Overview
Problem
Endoscope systems with solid state image sensors often suffer from defective pixels that produce abnormal signals, particularly blinking defective pixels due to noise and device defects, which result in image noise during live imaging, and existing methods for correcting these defects are inefficient.
Innovation Solution
An endoscope system and method that involves a light source unit, an image sensor with a plurality of pixels, an illumination controller, a difference calculation unit, a blinking defective pixel detection unit, an image output timing adjustment unit, and a pixel correction unit, which calculates difference data between dark images and a dark reference image to detect blinking defective pixels and corrects their signals using neighboring pixel signals, ensuring high-resolution image display.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the light source unit is turned off frequently to detect blinking defective pixels, then detection accuracy improves, but image output frame rate decreases
Solution Approach 1:
The system performs preliminary detection of blinking defective pixels during lights-out periods before actual image capture. By pre-identifying defective pixels when the light source is off, the system prepares correction data in advance, allowing full-frame rate image output without interruption for detection.
Solution Approach 2:
The illumination controller turns off the light source unit periodically at predetermined intervals (e.g., every N frames) rather than continuously. This periodic illumination allows the system to balance between capturing images at full frame rate and performing blinking defective pixel detection during scheduled lights-out periods, maintaining both high productivity and detection accuracy.
2Productivity
If the light source unit remains continuously on for high frame rate imaging, then image output productivity improves, but blinking defective pixel detection becomes difficult
Solution Approach 1:
The system performs preliminary detection of blinking defective pixels during lights-out periods before actual image capture. By pre-identifying defective pixels when the light source is off, the system prepares correction data in advance, allowing full-frame rate image output without interruption for detection.
Solution Approach 2:
The illumination controller acts as an intermediary that coordinates between the light source unit and image sensor, creating scheduled lights-out periods that enable detection without permanently reducing frame rate. This mediator allows the system to switch between detection mode and full-speed imaging mode seamlessly.
3Measurement precision
If multiple dark images are captured and averaged to create a dark reference image, then detection accuracy improves, but processing time increases
Solution Approach 1:
The system performs preliminary detection of blinking defective pixels during lights-out periods before actual image capture. By pre-identifying defective pixels when the light source is off, the system prepares correction data in advance, allowing full-frame rate image output without interruption for detection.
Solution Approach 2:
Instead of requiring complete averaging of multiple dark images, the system uses a predetermined number of averaged dark images as reference data. This partial action approach provides sufficient detection accuracy while limiting processing time and computational load to acceptable levels.
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
Effectively detects and corrects blinking defective pixels, ensuring high-resolution image display by temporarily holding and outputting image data at predetermined timing, thereby reducing image noise and improving image quality.
Implementation Method 1
an image sensor having a plurality of pixels arranged two-dimensionally, each of the plurality of pixels being configured to receive light and perform photoelectric conversion on the received light to output an electric signal
Data Source
AI summary
An endoscope system includes: a light source; an image sensor having pixels, each performing photoelectric conversion on received light to output an electric signal, and the image sensor imaging a subject to generate image data of the subject; a difference calculation unit that calculates, for each pixel, difference data between a dark image and a dark reference image, the dark image being output from the image sensor during lights-out time when the light source is turned off, and the dark reference image having been preliminarily obtained by averaging dark images generated by the image sensor; a detection unit that detects in the difference data a pixel whose pixel value is a threshold or more, as a blinking defective pixel in the image sensor; and a correction unit that corrects the electric signal output from the blinking defective pixel, using electric signals output from neighboring pixels of the blinking defective pixel.