Automated Tracking Turns Cell Culture into Numbers Figure 10. Cell density dependent cell area. The solid line shows the decrease of cell area with increasing cell density; the stained area depicts the distribution (standard deviation) of cell area. The solid line is calculated using the reference data, the dotted line using the threshold based cell detection algorithm described in this work. The confluency (red) is calculated in percent, i.e. the sum of all cell-pixels divided by the pixelsize of the overall observed area. doi:10.1371/journal.pone.0027315.g010 Figure 11. Life time distribution. (A) displays the histogram data of the life time distribution (time between consecutive mitoses) and a fitted normal distribution for all path lengths before and after t = 36 h (onset of contact inhibition, cf. figs 10 & 11); (B) illustrates the prolongation and distribution of the life time when reaching confluency. doi:10.1371/journal.pone.0027315.g011 PLoS ONE | www.plosone.org 11 November 2011 | Volume 6 | Issue 11 | e27315