Disclosed is an autonomous distributed system for detecting and tracking a falling object within a region being monitored by using a plurality of camera assemblies cooperating with each other, and disclosed is a camera assembly therefor. Each of the camera assembly, normally, operates in a falling object detecting mode, but, when detecting a falling object, shifts to a tracking mode. In the tracking mode, a degree of danger of the falling object is determined by referring to the size of the falling object in real space and the movement of a falling. In addition, when the falling object is further tracked and moved outside of the angle of view, a search request including information of the degree of danger as to the falling object is issued to surrounding camera assemblies, such that the multiple camera assemblies search for the falling object in cooperation.