Ophthalmological Image Distortion Correction via Reference Template Matching
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Solution Overview
Problem
Scanning-type ophthalmic imaging apparatuses face challenges in obtaining high-resolution images with wider angles of view due to increased photographing time, leading to eye movement and distortion issues, which existing methods struggle to effectively address.
Innovation Solution
An ophthalmological image processing apparatus that utilizes a second image, taken under less distorted conditions, as a template for local matching and distortion correction, allowing for the detection and correction of distortions in the first image, even when photographed at different times and with varying illumination conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the scanning-type imaging apparatus photographs at a larger angle of view or higher resolution, then the image quality and coverage are improved, but the photographing time increases causing eye movement and distortion
Solution Approach 1:
The system performs preliminary actions by capturing a reference image before the main photographing process, and uses this reference image to predict and correct eye movement during subsequent high-resolution imaging. This preliminary capture of baseline data enables real-time correction without extending the actual photographing time.
Solution Approach 2:
The system introduces an intermediary processing mechanism that uses a reference image as a mediator between the captured image and the final output. By comparing the captured image with the reference image and calculating displacement amounts, the system indirectly corrects eye movement effects without requiring direct real-time tracking during photographing.
2Measurement precision
If the photographing time increases to achieve higher resolution, then the image detail is improved, but eye movement during scanning causes distortion
Solution Approach 1:
The system implements feedback by continuously comparing the captured image with the reference image, calculating the displacement amount, and using this information to correct the final image. This feedback loop ensures that eye movement effects are compensated for, maintaining image reliability even during extended photographing periods.
Solution Approach 2:
The reference image is captured in advance as a baseline, allowing the system to predict and correct eye movement patterns during the actual high-resolution photographing. This preliminary establishment of a reference state enables reliable correction without requiring the subject to maintain perfect fixation throughout the entire process.
3Measurement precision
If multiple images are captured to improve image quality through compositing, then the S/N ratio is improved, but the total processing time increases
Solution Approach 1:
The reference image is captured in advance and stored for reuse across multiple photographing sessions. This preliminary capture eliminates the need to recapture reference data for each composite image, significantly reducing the time required for multiple image processing operations while maintaining improved S/N ratios through compositing.
Data Source
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AI summary
An ophthalmological image processing apparatus acquires a plurality of images of a subject eye photographed in a scanning-type imaging optical system, sets any one of the plurality of images as a template, sets corresponding points or corresponding regions between an image of the subject eye and the template at a plurality of positions of each of the image of the subject eye and the template, calculates a movement amount of each of the corresponding points or each of the corresponding regions, and corrects a distortion of the image of the subject eye with respect to the template based on the movement amount of each of the corresponding points or each of the corresponding regions.