Fig 1.
Sample swept-source OCT B-scan depicting the choroid layer and its sub-structures—Choriocapillaris, Sattler’s layer and Haller’s layer.
Notation: CIB—Choroid inner boundary; COB—Choroid outer boundary; CSI—Choroid-sclera interface.
Fig 2.
Schematic of proposed algorithm.
Fig 3.
Proposed algorithm depicted graphically.
(a) Raw OCT B-scan; (b) Denoised using Wiener filter; (c) Adaptive histogram equalized image; (d) Binarized image [30]; (e) Detected choroid boundaries [27]; (f) Binarized choroid layer (inverted); (g) Watershed segmentation; (h) Watershed segmentation post extended-minima; (i) Large vessel boundaries; (j) Innermost (linear interpolated) points of the vessels; (k) Smoothened Haller’s layer boundary; and (l) Algorithmic (yellow) vs (orange and red) manual demarcations.
Fig 4.
Automated vs manual markings of Haller’s layer; yellow—Automated, orange—Manual marking by grader-1, red—Manual marking by grader-2, yellow-red stripes—Choroid inner and outer boundaries.
Fig 5.
Statistical analysis: Automated vs manual methods.
Notation: M1—manual segmentation-1, M2—manual segmentation-2, M—average of M1 and M2, P—proposed.
Table 1.
Statistical analysis: Automated vs manual methods.
Notation: M1-manual segmentation-1, M2-manual segmentation-2, M-average of M1 and M2, P-proposed, Mq-mean, SDq-standard deviation, CVq-coefficient of variation, QMq-quotient of mean, QCVq-quotient of coefficient of variation, q takes AD, CC or DC.