Retinal OCT Axial Motion Correction Using Fourier Pattern Removal
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Solution Overview
Problem
Optical coherence tomography (OCT) scans of the eye are compromised by axial motion, leading to jagged and broken images and complicating automated data analysis, particularly in retinal multilayer segmentation, due to factors like patient movement, systemic operations, and mechanical vibrations.
Innovation Solution
A method and system for axial motion correction in OCT data using Fourier transform-based periodic pattern removal and orthogonal scan correlation to estimate and correct axial motion, employing multiple pairs of orthogonal scans and Fourier domain analysis without requiring additional registration scans.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If axial motion correction is applied using orthogonal retrace scans, then image quality improves, but the technique suffers from axial bulk motion and low image contrast when retrace scans cross the ONH or large vessels
Solution Approach 1:
The patent segments the retinal layer data to identify and remove periodic motion patterns. By dividing the axial motion correction into periodic components (identified through Fourier analysis) and non-periodic components, the system can selectively correct periodic artifacts while preserving genuine anatomical structures, avoiding the bulk motion problems that affect traditional orthogonal scan methods.
Solution Approach 2:
The patent applies partial action by selectively removing only the periodic frequency components associated with motion artifacts from the Fourier transform of the retinal data, rather than applying a blanket correction to all data. This targeted approach corrects periodic motion patterns without introducing the excessive correction that causes axial bulk motion and contrast loss in traditional methods.
2Object-affected harmful factors
If traditional axial motion correction methods are used, then some motion artifacts are reduced, but they fail to address both axial shift and shear (tilt) error simultaneously
Solution Approach 1:
The patent implements a universal correction algorithm that simultaneously addresses both axial shift and shear (tilt) errors. The Fourier-based periodic pattern removal method is applicable to various types of periodic motion artifacts regardless of their specific cause, making the system versatile for correcting multiple error types that affect OCT imaging of the retina.
Solution Approach 2:
The patent changes the parameter domain from spatial to frequency domain through Fourier transformation. By analyzing motion patterns in the frequency domain, the system can identify and remove periodic artifacts associated with both axial shift and shear errors, then transform the corrected data back to the spatial domain, achieving comprehensive error correction.
3Measurement precision
If additional registration scans are used for motion correction, then correction accuracy improves, but scan time and system complexity increase
Solution Approach 1:
The patent enables self-service by using the existing retinal layer segmentation data from the primary OCT scan to identify and correct periodic motion patterns. The system extracts periodic artifacts directly from the acquired retinal data without requiring separate registration scans, making the correction process self-sufficient and eliminating additional scan time requirements.
Solution Approach 2:
The patent makes the primary OCT scan data serve multiple functions: both diagnostic imaging and motion correction reference. By utilizing the retinal layer segmentation results for periodic pattern removal, the system eliminates the need for dedicated registration scans while maintaining correction accuracy, as the same scan data provides both the image to be corrected and the reference for correction.
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
Improves image quality and reduces failures in automated retinal layer segmentation by accurately correcting axial motion, enhancing the accuracy of retinal thickness mapping and vascular structure analysis.
Implementation Method 1
determining a model of a Fourier transform applicable to a segment of the first retinal layer; and removing one or more transform frequencies associated with the OCT data using the model of the Fourier transform
Data Source
AI summary
A method and system for correcting axial motion in optical coherence tomography (OCT) data is provided. The method includes collecting, by a processor disposed of in an OCT device, a volume scan of an eye; segmenting a first retinal layer within the volume scan; applying an algorithm for periodic pattern removal of OCT data in the first retinal layer by determining a model of a Fourier transform applicable to a segment of the first retinal layer; and removing transform frequencies associated with the OCT data using the model of the Fourier transform; determining a measure of an amount of axial motion in accordance with a difference of an amount of OCT data captured on a surface of the first retinal layer before and after application of the algorithm for periodic pattern removal; and correcting, the amount of axial motion in the OCT data of the first retinal layer.