Status flags for path classification and lineage construction.

The first 6 flags (bold) determine terminal starting / end points of paths. The next 2 flags indicate starting / end points which are in need for completion through either connection, correction, or removal from the tracking evaluation. Although the last flag ("merged") is not used to classify the ends of a path, it implies both a set "lost start" and "lost end" flag.*) The vicinity of the border is defined such that the distance between the centroid of the cell and the image border is smaller than a minimum distance (typically about 25–40 pixel, corresponding roughly to 50 µm).