derived information may lead to a parameterized cell culture, far exceeding the limits of present non-invasive cellular analysis in both, accuracy and biological relevance. Ultimately, validated cell tracking will prove to be an important advancement in the standardization of therapeutical and industrial cell culture. Finally, we provide the scientific community with two large reference data sets, which have been fully tracked and corrected by hand. These sets are supposed to be freely used as a benchmark system for tracking algorithms or other image based cell analyses. We sincerely hope that these data will help to establish a scientific discourse and that they may contribute to improve cell tracking within near future. Supporting Information Figure S1 Pancreatic stem cells (PSCs, data set C) in passage 31 were cultured and observed over a time period of three days and imaged at 10 different positions. The proliferation curves are shown in (A), the changes of confluency in (B,C). The last subfigure (D) displays the change of mean cell area of these different positions. The variances between the 10 curves are small. (TIFF) Figure S2 Human dermal fibroblast (HDF) (data set D) were cultured over more than 10 days and imaged at four positions. Anal- ogous to the figure S1, the proliferation curves are shown in (A), the changes of confluency in (B,C) and the change of mean cell area in (D). (TIFF) Table S1 Selected previous tracking work, compared to one another with respect to important technical details. The tracking tasks and the methods of evaluation are very diverse, making a direct comparison rather difficult. (DOC) Video S1 A culture of proliferating PSCs is shown during a time lapse experiment using oblique illumination. This image sequence was used to create reference data set A. (AVI) Video S2 A culture of proliferating PSCs is shown during a time lapse experiment using oblique illumination. This image sequence was used to create reference data set B. (AVI) Video S3 A culture of proliferating PSCs is shown during a time lapse experiment using phase contrast microscopy. This image sequence belongs to reference data set B. (AVI) Video S4 The complete genealogical tree for one cell is shown. This tree was reconstructed using the reference data set B. (AVI) Video S5 This video shows the proliferation of PSCs during a timelapse experiment. Video / position 1 / 10 is shown. (AVI) Video S6 This video shows the proliferation of PSCs during a timelapse experiment. Video / position 2 / 10 is shown. (AVI) References Automated Tracking Turns Cell Culture into Numbers Video S7 This video shows the proliferation of PSCs during a timelapse experiment. Video / position 3 / 10 is shown. (AVI) Video S8 This video shows the proliferation of PSCs during a timelapse experiment. Video / position 4 / 10 is shown. (AVI) Video S9 This video shows the proliferation of PSCs during a timelapse experiment. Video / position 5 / 10 is shown. (AVI) Video S10 This video shows the proliferation of PSCs during a timelapse experiment. Video / position 6 / 10 is shown. (AVI) Video S11 This video shows the proliferation of PSCs during a timelapse experiment. Video / position 7 / 10 is shown. (AVI) Video S12 This video shows the proliferation of PSCs during a timelapse experiment. Video / position 8 / 10 is shown. (AVI) Video S13 This video shows the proliferation of PSCs during a timelapse experiment. Video / position 9 / 10 of data set D is shown. (AVI) Video S14 This video shows the proliferation of PSCs during a timelapse experiment. Video / position 10 / 10 is shown. (AVI) Video S15 This videos shows the proliferation of HDFs during a time lapse experiment. Video / Position 1 / 4 is shown. (AVI) Video S16 This videos shows the proliferation of HDFs during a time lapse experiment. Video / Position 2 / 4 is shown. (AVI) Video S17 This videos shows the proliferation of HDFs during a time lapse experiment. Video / Position 3 / 4 is shown. (AVI) Video S18 This videos shows the proliferation of HDFs during a time lapse experiment. Video / Position 4 / 4 is shown. (AVI) Acknowledgments The authors would like to thank Selin Kahya, Caroline Weber and Michael Brehler for manual tracking and programming work. We are indebted to Sandra Danner and Tom A. Rapoport for invaluable discussions and proofreading the manuscript. Author Contributions Conceived and designed the experiments: DHR SS TB AMM CK. Performed the experiments: SS DHR TB. Analyzed the data: TB DHR. Contributed reagents/materials/analysis tools: TB DHR. Wrote the paper: DHR TB. 1. Eilken HM, Nishikawa S, Schroeder T (2009) Continuous single-cell imaging of blood generation from haemogenic endothelium. Nature 457: 896–900. 2. Rieger MA, Hoppe PS, Smejkal BM, Eitelhuber AC, Schroeder T (2009) Hematopoietic cytokines can instruct lineage choice. Science 325: 217–218. 3. 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