1 cell becomes 2 cells -- which cell does it follow?
My understanding is that it can follow both. "Once a cluster of supervoxels has been identified as a cell nucleus, the computer uses that information to find the nucleus again in subsequent images." That sounds like extraordinarily cool technology. Tracking the embryonic development of cells is currently very hard. For really simple organisms, each embryonic cell can be tracked to one or more fixed descendent cells in known locations. For most organisms however, where a given embryonic cell ends up is a non-deterministic process.