Fig. 2: Perturbed watershed method.
From: UNSEG: unsupervised segmentation of cells and their nuclei in complex tissue samples
a Input image fragment with two abutting nuclei. b–e The posterior global and local masks of the input image from which the global nucleus cluster mask and local cell membrane mask are extracted for downstream perturbed watershed analysis. f Global nucleus cluster mask with cuts corresponding to the local cell membrane mask. g Distance transform of this modified global nucleus cluster mask. h Adaptive distance-transform estimate obtained by thresholding the distance transform by davr (see “Methods”). i Initial (unperturbed) watershed segmentation. j–m Perturbed watershed segmentation computed after shifting all markers from their unperturbed positions to the left (Δx = − ⌊davr⌋), right (Δx = ⌊davr⌋), up (Δy = ⌊davr⌋), and down (Δy = − ⌊davr⌋) on ⌊davr⌋ = 5 pixels, respectively. n Output segmentation of two-nuclei cluster based on the perturbed watershed.
