Connectivity Preservation And Coverage Control Of A Directional Vision Sensor Network With Blind Spots

In recent years,visual sensor network has attracted more and more attention from scholars due to its unique advantages.It has been widely used in many fields such as environmental monitoring,medical field,industrial and agricultural production,and information collection.In addition,in terms of information connectivity,visual sensors can collect and transmit rich media stream information.At the same time,when GPS and base station signals are interrupted,it can still keep the network connected by relying on local visual information.But different from the omnidirectional static vision sensor,the directional vision sensor can move and rotate,which makes the information connection maintenance and coverage control of the network very complicated.Starting from this feature,this paper studies the connectivity and coverage control problem of directed vision sensor networks.The paper first describes the coverage perception model of the directed vision sensor,and describes the coverage performance of the node to the environment by defining the coverage strength.Based on this model,this paper proposes the feasible region of the sensor node.By restricting the movement and rotation of the node in the area,to ensure the connectivity of the network information connectivity topology.At the same time,in order to reduce the restriction of the connectivity of the information connection topology to the movement of nodes,this paper defines the core topology structure.In addition,considering the different requirements of the network for the connection mode,this paper proposes the full connection and chain connection maintenance strategies respectively.Since full connectivity has greater constraints on node motion,it is only discussed in Chapter 4,and chain connectivity is discussed in more depth in Chapter 5.In the coverage of a uniform environment,the coverage area is discretized into target points with a uniform density,and the rotation direction is judged by comparing the coverage intensity of the target points on the left and right sides covered by the sensor nodes to reduce the overlap coverage region between the sensor nodes.And the feasible region constraints proposed in Chapter 3 are used to determine the rotation angle and the motion step length,so that the nodes can spread while maintaining the network connectivity.The final simulation results show the feasibility of the connectivity-maintaining coverage control strategy.In a non-uniform environment,the coverage strength of the node to the target point is not only related to the relative distance and angle between them,but also to the information density of the target point itself,and the distribution of its density function value is uneven.Based on the gradient,this paper designs a coverage connectivity motion controller in a non-uniform environment,finds the optimal state of the node,optimizes the coverage performance of the network,and combines the chain connectivity maintenance strategy proposed in Chapter 3 to ensure that the network maintains connectivity while the nodes are moving.Simulation results show that this method can achieve good connectivity maintenance and coverage control in a non-uniform environment.