A system for monitoring the motion of objects is configured to identify objects meeting predetermined criteria appearing in a scene and to track the motion of identified objects across the scene. In a particular embodiment the system is configured to compile statistical data for multiple points or regions to indicate one or both of: the frequency with which objects are initialised at that region or point; and the frequency with which initialised objects cross the region or point. The initialisation data will indicate the areas in the scene where objects are most frequently initialised. If the statistical data shows an area of the scene in which objects are never initialised this might indicate that there is an obstruction between objects that need to be tracked and the detector. The path data will indicate the paths most frequently followed by objects. If there is a particularly well trodden path to and fro in a particular part of the scene this might distort the result of a count of people entering and leaving a region in the scene.