Energy Optimization of Wireless Visual Sensor Networks with the Consideration of the Desired Target Coverage

Wireless visual sensor networks (WVSN) have recently seen dramatic growth with technology development. These networks consist of a number of smart visual sensors (VSes) that can collect visual information, i.e., images and video captured in a network area. Optimizing the energy consumption and coverage are important contradictory challenges in WVSNs since increase in coverage leads to increase in energy consumption. Therefore, optimization of energy consumption by maintaining image quality defined by user or operator located in sink [quality of experience (QoE)] to be used in target tracking applications is addressed in this paper. The target coverage as well as the quality of the received image of the target are considered as the desired QoE. The novel two-dimensional target coverage model is also presented mathematically. This model is described as a function of the VS inherent parameters, the target position and the visual sensor position. Based on a convex optimization framework, a heuristic approach for the VS selection and the focal length adjustment is suggested to solve the optimization problem while maintaining high image quality. Simulation results are presented to verify the capability and efficiency of the proposed method in comparison with the optimal method (Exhaustive search method).