The presented algorithm keeps track of people walking within the field of view of a laser rangefinder while constructing a short-term model of the static environment. Background detection does not require a learning phase and is based on the extraction of simple geometric shapes and on the notion of their vitality introduced in this study. Object tracking is based on Multiple Hypothesis Tracking and Kalman Filtering, whereas separate Kalman Filters follow people's trajectories. The proposed method is experimentally evaluated.