  This article addresses the visual area coverage problem using a team of
Unmanned Aerial Vehicles (UAVs). The UAVs are assumed to be equipped with a
downward facing camera covering all points of interest within a circle on the
ground. The diameter of this circular conic-section increases as the UAV flies
at a larger height, yet the quality of the observed area is inverse
proportional to the UAV's height. The objective is to provide a distributed
control algorithm that maximizes a combined coverage-quality criterion by
adjusting the UAV's altitude. Simulation studies are offered to highlight the
effectiveness of the suggested scheme.
