Fundus Observation Apparatus Eye Movement Correction
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Solution Overview
Problem
Current fundus observation apparatuses using optical coherence tomography face challenges in capturing accurate 3-dimensional images due to eye movement or blinking during scanning, leading to potential distortion or incomplete image capture.
Innovation Solution
A fundus observation apparatus that includes an optical system for generating interference light, a scanning part for two-dimensional scanning, an image forming part for creating 3-dimensional images, and a correction part that adjusts image positions based on moving images and tomographic data to account for eye movement or blinking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If two-dimensional scanning with signal light is performed to capture 3-dimensional image, then three-dimensional tomographic information is obtained, but eye movement or blinking during scanning causes image distortion or incomplete capture
Solution Approach 1:
The system performs preliminary alignment by capturing a fundus image before OCT scanning and using it to pre-position the scanning region. This preliminary action ensures that the subsequent 3D scanning is centered on the correct anatomical location, reducing the impact of eye movements during the actual scanning process.
Solution Approach 2:
The system continuously monitors eye position during scanning using the fundus camera and provides real-time feedback to adjust the scanning position. When eye movement is detected, the system dynamically repositions the scanning region to maintain accurate image capture, thereby compensating for involuntary movements.
2Measurement precision
If scanning time is extended to improve image quality, then measurement accuracy increases, but probability of eye movement or blinking increases
Solution Approach 1:
The system performs preliminary alignment and region selection before the actual 3D scanning to ensure optimal positioning. This preliminary setup minimizes the need for adjustments during scanning, allowing for faster acquisition of high-quality images without requiring extended scanning time.
Solution Approach 2:
The system replaces mechanical scanning adjustments with optical and computational methods. By using the fundus camera for real-time positioning guidance and software-based image registration, the system achieves high-quality imaging without the mechanical delays associated with physical repositioning during scanning.
3Measurement precision
If fundus image is captured before OCT scanning for alignment, then scanning position accuracy improves, but additional time and complexity are required
Solution Approach 1:
The system merges the fundus camera and OCT scanner into a single integrated apparatus with shared optical paths and coordinated control. This integration allows simultaneous capture of fundus images and OCT data without requiring separate equipment, thereby improving positioning accuracy while minimizing additional complexity.
Solution Approach 2:
The integrated system serves multiple functions: the fundus camera provides both alignment guidance and diagnostic imaging, while the OCT scanner performs both structural imaging and positioning verification. This multi-functionality reduces the need for additional specialized equipment while maintaining high scanning position accuracy.
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
Enables the capture of highly accurate 3-dimensional OCT images even when the eye moves or blinks during scanning by correcting for positional misalignment in both the fundus surface and depth directions.
Implementation Method 1
generates interference light by superposing signal light that has passed through the fundus of an eye and reference light that has passed through a reference optical path
Implementation Method 2
optical coherence tomography that forms images of the surface morphology and internal morphology of an object by using a light beam from a laser light source
Data Source
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AI summary
The fundus observation apparatus 1 has a function to form tomographic images and 3-dimensional images of a fundus Ef by scanning signal light LS as well as a function to form a moving image (observation image K) of a fundus Ef during OCT measurement. Furthermore, the fundus observation apparatus 1 includes an x-correction part 231 and a y-correction part 232 for correcting a position in the fundus surface direction of the 3-dimensional image based on the observation image K, and a z-correction part 233 for correcting the position in the fundus depth direction of a 3-dimensional image, based on a tomographic image Gi of the fundus Ef based on the detection results of interference light LC of separately scanned signal light LS and reference light LR.