OCTA Vessel Annotator

Shortcuts

See the vessel first. Leave CLAHE on and raise the vesselness overlay until faint branches pop. You cannot annotate what you cannot see.
Trace with the live-wire (W), not the brush. Click once at a vessel start, move along it — the path snaps to the ridge. Click to anchor, Enter to lay it down at the measured vessel width.
Bulk-fill with the smart brush (S). Swipe roughly over a vessel; only pixels above the vesselness threshold take paint, so edges stay pixel-exact even with a sloppy stroke.
Split arteries and veins by tree (R). Imported labels arrive as Unclassified. Hover a trunk, press 1 or 2 — the whole connected tree flips class in one keystroke.
Repair breaks with Bridge (G). Click the two ends of a broken vessel; the least-cost path along the ridge reconnects them at the local width.
Finish with Cleanup. Despeckle, trim spurs, close. Then Ctrl+S and . to the next image.