Tomographic Image Noise Reduction via Phase Deviation Correction
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Solution Overview
Problem
Swept source optical coherence tomography devices face challenges in reducing noise, particularly Fix Pattern Noise (FPN), due to the high-speed wavelength variation of the light source, which complicates wavelength control and results in phase deviations across A-scan lines, leading to residual noise in tomographic images.
Innovation Solution
The method involves acquiring phase information of noise components from the spectrum interference signal, correcting phase deviations based on this information, and processing the signal to reduce noise, allowing for the extraction of a tomographic image with minimized noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high-speed wavelength variation is used to increase imaging speed, then productivity is improved, but phase deviations occur leading to increased noise in tomographic images
Solution Approach 1:
The patent applies preliminary action by acquiring phase information of noise components before final image reconstruction, and correcting phase deviations in advance. The system calculates phase information from the spectrum interference signal, corrects phase deviations based on this information, and then performs noise reduction processing. This preliminary correction approach prevents noise from being introduced during the imaging process while maintaining high-speed wavelength variation.
2Object-affected harmful factors
If DC subtraction is used to reduce FPN, then noise is reduced, but residual noise remains due to phase deviations caused by high-speed wavelength variation
Solution Approach 1:
The patent implements feedback by acquiring phase information from the spectrum interference signal itself and using this information to correct phase deviations. The system continuously monitors the phase characteristics of the noise components and adjusts the phase correction based on this feedback. This feedback mechanism ensures that phase deviations are accurately corrected, allowing DC subtraction to effectively reduce FPN without leaving residual noise.
3Device complexity
If phase correction is performed without accurate phase information, then processing is simplified, but noise reduction effectiveness is compromised
Solution Approach 1:
The patent performs preliminary acquisition of phase information from the spectrum interference signal before noise reduction processing. By calculating and storing phase information in advance, the system maintains processing simplicity while ensuring accurate phase correction. The pre-acquired phase information is then used to correct phase deviations during the noise reduction stage, achieving effective noise removal without excessive processing complexity.
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 effectively reduces noise in tomographic images by correcting phase deviations and subtracting average noise spectra, resulting in a clearer image with reduced FPN.
Implementation Method 1
the optical interference optical system obtains interference light by combining the measurement light flux, which are reflected by the object, and the reference light flux
Implementation Method 2
the optical interference optical system causes a light receiving device to receive the interference light
Data Source
AI summary
A method for reducing noise in a tomographic image, includes: acquiring phase information of a noise component signal, the signal being provided as a signal corresponding to a noise component of the tomographic image and included in a spectrum interference signal output from a detector of a swept source optical coherence tomography device; acquiring a tomographic image in response to a spectrum interference signal with a corrected phase deviation based on the acquired phase information; and reducing the noise component of this tomographic image.