Optical microscopy in 2 or 3 dimensions allows extensive observations of the motility and morphology of living cells, in culture or in tissue. This leads to an exploding accumulation of imaging data and shifts the bottleneck from data acquisition to data analysis. Manual image analysis is often either impossible or exceedingly time‐consuming and subject to uncontrollable user bias and errors. Computerized methods promise to ensure fast, accurate and reproducible processing, but the basic image analysis functions available in standard commercial software are generally not adapted to the complexity of biological images. For this reason, we develop methods based on active contours, a powerful and flexible technique to segment and track objects, that has become very popular in computer vision research. Here, we describe the main benefits and limitations of active contours for our application, and our efforts to adapt and improve these methods for the analysis of cellular dynamics.