OCT Imaging Apparatus Eye Movement Correction
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Solution Overview
Problem
Current optical coherence tomographic imaging apparatuses face challenges in capturing undistorted tomographic images due to subject eye movements, particularly involuntary movements like flicks, which can lead to image distortion and misdiagnosis, as existing tracking systems have a time lag and are unable to correct scanning positions quickly enough to account for rapid eye movements.
Innovation Solution
The apparatus detects subject eye movements and blinks by analyzing a series of fundus images, allowing for real-time scanning position corrections between image acquisitions, either by restarting the scan from a previous position or adjusting the scanning unit to compensate for movement, thereby reducing distortion in the captured images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the scanning unit scans the fundus a plurality of times to capture multiple tomographic images for averaging processing, then the image definition is improved, but the image capturing time increases causing eye movement during acquisition
Solution Approach 1:
The system performs preliminary detection of eye movement using fundus images captured by the scanning unit before the main OCT imaging sequence. This preliminary action allows the control unit to predict and compensate for eye movement during the subsequent multiple scans, enabling accurate image averaging without requiring extended capture time that would allow uncorrected eye movement to degrade image quality.
Solution Approach 2:
The system implements a feedback mechanism where fundus images are continuously captured and analyzed to detect eye movement. The detected eye movement information is fed back to the control unit, which adjusts the scanning positions and timing of subsequent OCT scans in real-time. This feedback loop ensures that multiple scans are acquired at the correct positions despite eye movement, maintaining image definition while managing capture time.
2Measurement precision
If the tracking function corrects scanning positions based on detected eye movement, then the scanning position accuracy is improved, but the correction time lag reduces effectiveness for rapid eye movements
Solution Approach 1:
The system captures fundus images and detects eye movement before initiating the main OCT imaging sequence. This preliminary detection provides advance information about eye movement trends, allowing the control unit to pre-adjust scanning positions or modify scan timing to anticipate and compensate for rapid eye movements before they occur during image acquisition.
Solution Approach 2:
The system dynamically adjusts the scanning parameters and timing based on real-time eye movement detection. Rather than using fixed correction intervals, the control unit modifies scan positions, scan rates, and timing on-the-fly in response to detected eye movement patterns. This dynamic adaptation allows the system to maintain scanning position accuracy even during rapid eye movements by flexibly responding to changing conditions.
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 tomographic images with reduced distortion from eye movements, improving diagnostic accuracy by minimizing the impact of involuntary eye movements and blinks on image quality.
Implementation Method 1
utilizes multi-wavelength light wave interference
Implementation Method 2
irradiating a sample with measuring light which is low-coherent light, and measuring backward scattering light from the sample by using an interferometer
Data Source
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AI summary
An optical coherence tomographic imaging apparatus (100) includes a movement amount acquisition unit (300) configured to acquire the amount of subject's eye (E) movement based on a plurality of images of the subject's eye acquired at different times, a determination unit (300) configured to determine whether the amount of subject's eye movement before a scan by the scanning unit (122) exceeds a threshold value, and a control unit (300) configured to, in a case the amount of subject's eye movement before the scan is equal to or smaller than the threshold value, control the scanning unit (122) to perform scanning position correction between a scan and the next scan based on the amount of movement.