Novel visual sensor deployment algorithm in PTZ wireless visual sensor networks

Abstract

In this paper, we consider the visual sensor deployment algorithm in Pan-Tilt-Zoom (PTZ) Wireless Visual Sensor Networks (WVSN). With the capability of panning, tilting and zooming, the sensor visual coverage can be enlarged and fewer visual sensors are needed as compared to the traditional WVSN. We divide the Field of View (FoV) of the PTZ sensor into two regions, Direct Coverage Region (DCR) and PTZ Coverage Region (PTZCR). In the PTZCR, the visual sensor need to pan-tilt-zoom the camera angle to cover the object. Because pan-tilt-zoom is a slow mechanic operation, visual sensor might not be able to adjust the angle in time to capture the visual data. One possible way to alleviate this problem is to make sure the PTZCR are covered by M sensors. With large M, there is a high probability of adjusting the camera in time to capture the visual data at the PTZCR by at least one camera. We tackle this visual sensor deployment problem in PTZ WVSN to make sure that each area is either covered in the DCR of a single visual sensor or in the PTZCR of M sensors. Then novel heuristic, PTZA algorithm, is proposed to solve the problem. In the computational experiments, we find out that PTZ capable camera sensor could significantly reduce the number of deployed sensors especially in smaller sensing range and smaller camera span angle.