Optical Coherence Tomography Retinal Image Orientation Detection
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Solution Overview
Problem
Current optical coherence tomography (OCT) systems face challenges in efficiently aligning retinal images to the correct position and orientation on a tomogram, particularly for non-standard eye types, leading to suboptimal imaging quality and depth sensitivity due to reliance on manual or pixel analysis methods that can result in false positives and require resource-intensive dispersion correction.
Innovation Solution
The OCT apparatus employs a method to determine the initial orientation and position of the retinal image by calculating the zero delay line position based on the eye's axial length and refraction error, using a combination of test moves and target moves to adjust the reference mirror, allowing for real-time correction and improved alignment for a wide range of eye types.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual or pixel analysis methods are used to align retinal images on tomograms, then the alignment can be performed, but the process is resource-intensive and may result in false positives
Solution Approach 1:
The patent changes the approach from manual/pixel analysis to using calculated parameters (axial length, refraction error) to determine the zero delay line position. This mathematical parameter-based method replaces complex image processing while maintaining alignment accuracy.
Solution Approach 2:
The patent replaces manual mechanical adjustment and pixel-based image analysis with an automated calculation system that uses optical parameters (axial length, refraction error) to directly compute the correct image position, eliminating the need for resource-intensive image processing.
2Ease of operation
If the reference mirror is adjusted using conventional methods to position the tomographic image, then the image position can be changed, but the process requires time-consuming iterative adjustments
Solution Approach 1:
The patent performs preliminary calculations of the zero delay line position based on axial length and refraction error before actual imaging. This pre-calculation eliminates the need for time-consuming iterative adjustments during the imaging process, as the correct position is determined in advance.
Solution Approach 2:
The system uses the eye's own optical parameters (axial length, refraction error) to automatically determine the correct image positioning, eliminating the need for external manual intervention or iterative trial-and-adjustment processes.
3Adaptability or versatility
If standard alignment methods are used for all eye types, then the process is simplified, but imaging quality deteriorates for non-standard eye types
Solution Approach 1:
The patent applies local quality by tailoring the alignment calculation to each eye's specific optical parameters (axial length, refraction error). Instead of a universal alignment method, the system calculates the zero delay line position specific to each patient's eye characteristics, ensuring optimal imaging quality for all eye types.
Solution Approach 2:
The patent creates a universal calculation method that works for all eye types by using fundamental optical parameters (axial length, refraction error) that can be measured for any eye. This single approach adapts to different eye types without requiring multiple specialized methods.
4Measurement precision
If dispersion correction is performed using conventional methods, then image accuracy can be improved, but the processing load increases significantly
Solution Approach 1:
The patent extracts the essential alignment information from complex image processing by using only the fundamental optical parameters (axial length, refraction error). This extraction approach separates the critical alignment function from resource-intensive image processing, maintaining accuracy while improving efficiency.
Solution Approach 2:
The patent replaces complex image processing mechanics with simple mathematical calculations based on optical parameters. This substitution eliminates the need for resource-intensive dispersion correction algorithms while maintaining image accuracy through parameter-based positioning.
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 fast, reliable, and efficient alignment of retinal images, enhancing imaging quality by reducing processing load and accommodating various eye types, thereby improving real-time imaging capabilities and sensitivity.
Implementation Method 1
creates a tomogram using interference light, the interference light arising from interference between measurement light from a sample arm of the OCT apparatus and reference light from a reference arm of the OCT apparatus
Data Source
Figure 1A~1B
Figure 2
Figure 3A~3B
AI summary
A method of an optical coherence tomography apparatus for positioning an image of an object on a tomogram comprising: initialising an optical path length of the optical coherence tomography apparatus so that an image of the object can be viewed on the tomogram at an initial position; performing a test move by changing the optical path length in a first direction by a first distance; observing a change in the tomogram of the object as a result of the test move; and determining, from the observation, whether an initial orientation of the image of the object was a normal orientation or an inverted orientation.