Speckle reduction in optical coherence tomography images
AssigneeTopcon Corporation
InventorsJun CHENG, Jiang LIU, Wing Kee WONG, Masahiro AKIBA
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Abstract
An optical coherence tomography (OCT) image composed of a plurality of A-scans of a structure is analysed by defining, for each A-scan, a set of neighbouring A-scans surrounding the A-slices scan. Following an optional de-noising step, the neighbouring A-scans are aligned in the imaging direction, then a matrix X is formed from the aligned A-scans, and matrix completion is performed to obtain a reduced speckle noise image.
Claims10
A computer-implemented method of enhancing an optical coherence tomography (OCT) image composed of a plurality of A-scans, each A-scan being indicative of a structure imaged in a predefined direction, the A-scans being grouped as one or more B-scans, the method comprising, for each A-scan:
- (a) defining a respective neighbourhood surrounding the A-scan;
- (b) aligning the A-scan in the pre-defined direction with other A-scans in the respective neighbourhood;
- (c) using the aligned A-scans to form a first matrix X, respective columns of the first matrix being the aligned A-scans;
- and
- (d) seeking a second matrix which the minimizes a cost function indicative of the difference between the first matrix X and the second matrix, the second matrix being constrained to obey a complexity constraint.
A method according to any preceding claim comprising a pre-step of noise reduction in the plurality of A-scans.
A method according to any preceding claim wherein step (c) is performed by:
- defining a first A-scan group consisting of one or more A-scans including the A-scan;
- and
- for each neighbouring A-scan:
- (i) defining a second respective A-scan group, the second respective A-scan group consisting of one or more A-scans including the neighbouring A-scan;
- (ii) seeking a respective translation value which, if the one or more A-scans of the respective second A-scan group are translated in the imaging direction by the translation value, minimises a difference between the first A-scan group and the second A-scan group;
- and
- (iii) translating the neighbouring A-scan by the respective translation value.
Dependencies are inferred from the claim text.