I. INTRODUCTION
Nowadays ambient surveillance has become very popular in our life and it plays a very important role in the security, both in civilization and military. In public spaces, such as subway stations, parks, and streets, various types of camera surveillance systems are installed. These systems could use only fixed cameras (i.e., cameras which are setup at fixed position, could or could not change angles of view) [3], [14], only mobile cameras (i.e., cameras which can move around) [12], or hybrid (i.e., both fixed and mobile cameras) [5] as input sensors in order to record all activities happening inside certain covered areas. Among these systems, fixed camera system have known as the most popular system and gained several remarkable results in public security.