Automatic directional analysis of cell microscopy images

Nuclei and actin filaments are important components inside eukaryotic cell, and their shapes and directions can be affected by the geometry and stiffness of culturing substrate. In this paper, methods to detect orientation of actin filament and nucleus automatically in microscopy images are proposed. In actin filament image, ROI region is obtained using morphological operator and gradient. Derivative-based method is employed to measure the direction of actin filaments in each subarea. In nucleus images, level set with intensity adjustment is applied to segment nuclei. The nuclei are further approximated using ellipse fitting. The direction and axis ratio of nuclei are measured based on the fitted ellipses. The statistical results show that the alignment orientations of nuclei and actin filaments both exhibit biphasic distributions.