Schematic diagram of image processing. Top panel: A phase-contrast image was taken for measurements of cell dimensions before acquisition of the time-lapse sequence of sfGFP-MinD oscillation. Middle panel: The fluorescence image of a cell was processed by projection of the intensity values onto the medial axis. The procedure was applied to all cell images in the entire time-lapse sequence (left). The intensity at different axial positions was plotted to visualize the fluctuations in fluorescence intensity, which indicated changes in protein concentration (middle). Fitting curves were generated using the intensity profiles of the same cell in the time-lapse sequence (right). Lower panel: The intensity profiles of different cells were projected into one dimension, sorted by cell length, and compiled into a kymograph (left). The fitted curves of individual cells were presented in XY plots followed by calculation of the wave slope (λN) and the intensity ratio (IRatio) (right).
