Fig 4. Visual demonstrations of finite-length “particle” evolutions.

Four image features, which prove to be problematic to capture in segmentation (leaf tips, leaf axils, leaf joins and leaf twists), lead to different stopping criteria. Particle evolution has stopped in (a) after reaching a leaf corner/tip, in (b) after reaching a leaf axil, in (c) after reaching an intersection of two leaves, and in (d) after passing over a leaf twist.