OCTARA (On Work)

This is a implementation of OCTARA (Optical Coherence Tomography Angiography Ratio Analysis) algorithm using Python.

According to the paper:

Introduction

we introduce Topcon’s novel, patent (under examination) motion contrast measure using aratio method, named OCTARA (OCT AngiographyRatio Analysis), where the full-spectrum is kept intact and therefore the axial resolution is preserved. It is shown that Topcon’s innovative method provides advantages over differentiation-based approaches while possessing improved sensitivity over methods based on amplitude decorrelation.

Method

Using DRI OCT, we performed SS-OCT imaging at 100,000 A-scans per second in both healthy and diseased eyes. Volumetric OCT scans were acquired over a 3 mm x 3 mm field of view in about four seconds of total OCT scan time. Each B-scan position was repeatedly scanned 4 times.

For OCTA processing with OCTARA, B-scan repetition at each scan location were registered. OCTA images were generated by computing a ratio-based result, r, between corresponding image pixels:

$r(x, y)=1-\frac{1}{N} \sum_{i, j}^N \frac{\min \left(I_i(x, y), I_j(x, y)\right)}{\max \left(I_i(x, y), I_j(x, y)\right)}$

where I(x,y) is the OCT signal intensity, N is the number of scanned B-scan combinations at the given location, and i and j represent the two frames within any given combination of frames.

mburaozkan/OCTARA

OCTARA (On Work)

Introduction

Method