OCT Phase Drift Correction via Depth-Averaged Profiles
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Solution Overview
Problem
Phase instability and movement-related errors in optical coherence tomography (OCT) systems affect the accuracy of OCT angiography and CAO-OCT measurements, leading to suboptimal image quality and reliability.
Innovation Solution
An ophthalmologic information processing apparatus that generates a phase difference profile by averaging phase differences in the depth direction of OCT data, extracts phase drift, and corrects the phase of OCT data to stabilize measurements, thereby reducing noise and structure-derived phase shifts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If phase correction is performed using conventional methods on OCT data, then measurement accuracy is improved, but phase instability and movement-related errors still affect OCT angiography and CAO-OCT measurements
Solution Approach 1:
The patent segments the phase correction process into multiple distinct steps: generating phase difference profiles between adjacent B-frames, extracting phase drift components from these profiles, and applying separate correction operations for different types of phase errors. This segmentation allows targeted correction of movement-related errors while preserving genuine phase information.
Solution Approach 2:
The patent performs preliminary phase stabilization by generating phase difference profiles and extracting phase drift information before conducting OCT angiography or CAO-OCT measurements. This preliminary action removes movement-related phase errors in advance, ensuring that subsequent measurements are not affected by phase instability.
2Manufacturing precision
If phase correction processing is applied to OCT data, then image quality is improved, but processing complexity increases
Solution Approach 1:
The patent extracts only the essential phase drift information from phase difference profiles by focusing on depth-averaged phase changes. This extraction approach isolates the critical correction data needed for phase stabilization while discarding redundant information, thereby simplifying the overall processing complexity.
Solution Approach 2:
The patent transforms the phase correction problem from a two-dimensional spatial domain operation to a depth-averaged one-dimensional profile analysis. By averaging phase differences along the depth direction to create phase difference profiles, the method reduces computational complexity while maintaining correction effectiveness.
3Reliability
If conventional phase correction methods are used, then some phase errors are corrected, but noise and structure-derived phase shifts remain
Solution Approach 1:
The patent converts the harmful effects of noise and structure-derived phase shifts into beneficial information by using depth-averaged phase difference profiles. These profiles capture genuine tissue phase changes while averaging out random noise, and the extraction process identifies systematic structure-derived shifts that can be corrected.
Solution Approach 2:
The patent implements a feedback mechanism where phase difference profiles are continuously generated from adjacent B-frames, phase drift is extracted and analyzed, and correction amounts are adjusted based on the extracted information. This closed-loop feedback ensures that noise and structure-derived phase shifts are systematically identified and corrected.
Data Source
AI summary
An ophthalmologic information processing apparatus according to the embodiments include a generator, an extractor, and a phase correction unit. The generator is configured to generate a phase difference profile by performing averaging processing in a depth direction on phase differences obtained by calculating for each depth position of A-lines between two adjacent B-frames of complex OCT data of a subject's eye. The extractor is configured to a phase drift from the phase difference profile generated by the generator. The phase correction unit is configured to correct a phase of first complex OCT data of any one of the two B-frames based on the phase drift extracted by the extractor.