There is provided a method for monitoring a first subject in an environment of interest using a first movement sensor for measuring movements of the first subject, and a first motion sensor in the environment of interest for measuring motion in a first sensing region, the method comprising obtaining measurements of the movements of the first subject over time from the first movement sensor； obtaining measurements of the motion in the first sensing region from the first motion sensor； and determining if motion measured by the first motion sensor is motion by the first subject by comparing the measurements of the movements and the measurements of the motion.
