Step-by- step image processing algorithm for FD calculation.

(a) The original two-channel image of the cell (F-actin and cell nucleus stained with Rh-Ph and Hoechst, respectively) was captured in 2048 x 2048-pixel resolution. (b) The blue channel (DAPI, cell nuclei) of the original image was isolated, binarized and color filled. (c) The minor and major axes of ellipse approximating the cell nuclei were found. (d) The original image is rotated in order that the major axis of ellipse becomes parallel to the X axis of the image. (e) The initial size of box grid is chosen as smallest square with power of two in which the ellipse approximating the cell nuclei is inscribed. The center of the box is in the ellipse’s centroid. The red channel (F-actin, Rh-Ph) of the original image is binarized (f), skeletonized (g) and processed using box counting method (h) using the calculated box size (e) in an initial iteration.