Fig. 4

Images illustrating the sequence of operations for filament identification. a Image obtained after binarization. b Colormap of euclidean distance-mapping, used as measure of thickness. c Agglomerates identified in the previous step are removed from the original binarized image. d For better morphological characterization, the remaining objects are skeletonized. e A pruning operation using geodesic-distance transform is performed for isolation of spines. f Colormap of RRG, which provides a measurement of elongation for debris elimination