The stability of ILEE and other classic image thresholding approaches for cytoskeleton segregation in confocal images. The coefficient of variation (CV*) of each index rendered by each approach in Fig. 4 d were calculated and visualized as a heatmap. O, Ostu; T, Triangle; L, Li; Y, Yan; N, Niblack; S, Sauvola; I, ILEE. ILEE has a dominantly low CV* (i.e., high stability) over diverse sample for occupancy, linear density, skewness, CV, or one of the lowest for other indices. Note that the CV* of computed indices in the figure and the fluorescence CV of a sample, which is a cytoskeletal index, are different concept.