Visual surveillance by depth from focus

This paper aims at describing a visual surveillance prototype system able to monitor a bounded (in depth) area by using a depth-from-focus approach. The single visual camera utilized is characterized by an adjustable lens objective controlled by a host computer. In this way, the system is capable to detect possible intruders entering in the controlled zone, recovering the range information by a depth-from-focus method, and tracking the incoming entity by using a simple strategy. Tracking is performed by computing the range distance such as to keep in focus the moving object that has violated the area. This method is based on an adaptive regulation strategy of the camera parameters which makes the system robust to lighting variations occurring in real environment. Preliminary results show the goodness of the proposed approach, especially concerning the depth information recovery