OCT Imaging Error Detection via Correlation Analysis

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Solution Overview

Problem

Conventional ophthalmologic imaging techniques using optical coherence tomography (OCT) face challenges in accurately capturing images due to eye movements and blinking, as the high repetition rate of OCT scans exceeds the frame rate of video cameras, leading to potential missed detections and time-consuming identification of affected scans.

Innovation Solution

An ophthalmologic imaging apparatus combining a swept source OCT system with a fundus camera, utilizing a processor to analyze both OCT and fundus images in real-time, detects eye movements and blinking by calculating correlation coefficients and mean square errors, allowing for immediate correction and re-scanning of affected areas.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the OCT scan repetition rate is increased to improve imaging speed and productivity, then productivity is improved, but the ability to detect eye movements and blinking deteriorates because the video camera frame rate cannot keep up

Engineering Contradiction:
ImproveOCT scan repetition rateVSAvoideye movement detection accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent uses OCT data itself as an intermediary to detect eye movements and blinking. Instead of relying solely on video camera footage, the system analyzes OCT scan data to identify movements, using the OCT signals as a mediator between the high-speed scanning and the lower-frame-rate video camera for detection purposes.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system implements feedback by continuously monitoring OCT scan data for signs of eye movement or blinking, then using this information to adjust scanning parameters or trigger rescanning. The detection results feed back into the scanning control to maintain image quality despite movements.

Inventive Principle:
Principle #23Feedback

2Device complexity

If conventional video camera-based tracking is used to monitor eye movements, then device complexity is reduced, but detection reliability deteriorates because movements between frames cannot be detected

Engineering Contradiction:
Improvedetection system complexityVSAvoidmovement detection reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The OCT system performs dual functions: it both acquires imaging data and detects eye movements/blinking. The same OCT scan data used for imaging purposes is also analyzed to detect movements, eliminating the need for separate dedicated detection hardware and improving reliability through multi-functional use of the OCT system.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The OCT system monitors its own scanning environment for movements using its own data. The system serves itself by using its imaging data to detect disturbances (eye movements) that affect its own imaging quality, enabling self-correction through rescanning or parameter adjustment.

Inventive Principle:
Principle #25Self-service

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 enables the acquisition of highly accurate OCT images by effectively detecting and correcting for eye movements and blinking, reducing the likelihood of image errors and improving the precision of OCT imaging.

Implementation Method 1

acquire data by scanning a subject's eye using optical coherence tomography (OCT)

Methodology Applied
Scientific EffectOptical coherence tomography:

Implementation Method 2

photograph the subject's eye to obtain front images

Methodology Applied
Scientific EffectOptical reflection: Reflection

Implementation Method 3

detect eye movements and blinking by calculating correlation coefficients and mean square errors

Methodology Applied
Scientific EffectCorrelation analysis:

Implementation Method 4

detect eye movements and blinking by calculating correlation coefficients and mean square errors

Methodology Applied
Scientific EffectMean square error calculation:

Data Source

PatentEP3821791A1Ophthalmologic imaging apparatus
Publication Date: 2021.05.19 TOPCON CORPORATION
  • EP3821791A1 patent drawingFigure 1
  • EP3821791A1 patent drawingFigure 2
  • EP3821791A1 patent drawingFigure 3

AI summary

An ophthalmologic imaging apparatus of an embodiment includes a data acquisition device, a photographing device, a controller, and an error detector. The data acquisition device acquires data by scanning a subject's eye using optical coherence tomography. The photographing device photographs the subject's eye to obtain a front image. The controller controls the data acquisition device to perform a series of scans along a preset path group. The error detector detects an error based on a series of data acquired by the series of scans and two or more front images that include one or more front images obtained by the photographing device corresponding to the series of scans.