Endoscope Rolling Distortion Control via Dual Exposure Modes
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Solution Overview
Problem
Endoscope apparatuses using CMOS imagers face challenges with rolling shutter distortion due to time differences in exposure timing between lines, especially in moving subjects or when the distal end is difficult to fix, leading to measurement errors in industrial inspections.
Innovation Solution
The endoscope apparatus includes a light source control unit, imaging device control unit, rolling distortion determination unit, and mode setting unit, which switch between simultaneous exposure lines and row-by-row scanning modes to control illumination and image capture, ensuring synchronized exposure across all pixels and minimizing rolling distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If sequential line exposure reading (rolling shutter operation) is used in CMOS imager, then power consumption is reduced and circuit configuration is simplified, but rolling shutter distortion occurs in images when camera or subject is moving
Solution Approach 1:
The patent divides the pixel array into multiple regions (first region and second region) that can be exposed and read out simultaneously or in overlapping time periods. This segmentation allows different parts of the image to be captured at different times, enabling correction of rolling shutter distortion by combining data from multiple regions while maintaining the efficiency benefits of sequential reading.
Solution Approach 2:
The patent implements preliminary action by performing simultaneous exposure in multiple regions before completing the full image capture. The first region is exposed and read out while the second region is being exposed, creating overlapping time periods that allow for distortion correction. This preliminary exposure strategy enables the system to capture sufficient image data without waiting for complete sequential reading of all pixels.
2Manufacturing precision
If global exposure is performed to eliminate rolling distortion, then all pixels are exposed simultaneously, but the available charge storage period must be managed carefully to avoid loss of information
Solution Approach 1:
The patent segments the pixel array into multiple regions with different exposure and readout timing. By dividing the image into a first region and second region, the system can manage charge storage periods separately for each region, allowing simultaneous exposure while maintaining sufficient storage time for all charges before reading begins. This prevents charge overflow and information loss.
Solution Approach 2:
The patent implements dynamic control of the readout process by adjusting the timing and order in which different regions are read out. The system dynamically manages the charge transfer and reading sequence to ensure that all charges are read within their available storage periods while maintaining simultaneous exposure across regions. This dynamic timing adjustment prevents charge loss while achieving global exposure benefits.
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 solution effectively reduces rolling distortion, improving image quality and measurement accuracy by ensuring synchronized exposure across all pixels, even in dynamic inspection scenarios.
Implementation Method 1
The imaging device includes a plurality of pixels disposed in a matrix and generates pixel signals of the pixels based on the optical image
Data Source
AI summary
When a first mode is set in an endoscope apparatus, a light source control unit causes a light source to be turned on during a period including all or a part of a period during which available storage periods of pixels in all simultaneous exposure lines. An imaging device generates a first image. When a second mode is set, the light source control unit causes the light source to be turned on during a period including all of the available storage period of the pixels in each of a plurality of rows. The imaging device generates a second image. The rolling distortion determination unit determines a situation of occurrence of rolling distortion using the first image and the second image.