Research On Wake-up And Image Transmission In Wireless Multimedia Sensor Networks

I ith the increasing complexity of the monitoring environment,the traditional wireless sensor networks(WSNs)can not meet the needs of monitoring in some occasions.Wireless multimedia sensor networks(WMSNs)came into being.The addition of multimedia information such as audio,video and image makes the collection of environment information more accurate and comprehensive in wireless multimedia sensor network.However,the problems of large energy consumption and large amount of data transmission in wireless multimedia sensor network seriously affect the survival time of the network.In this paper,the problem of camera node wake-up and image transmission in the process of image acquisition is studied.This thesis briefly introduces the development and application of WMSNs,and studies the basic theory of camera node wake-up strategy,multi node cooperation,wavelet transform,the basic principles of wavelet transform and image coding algorithm in the field of image processing.Aiming at the problem of camera node wakeup in WMSNs,considering the camera node wakeup strategy,the relative occurrence location of events,and the energy consumption of camera nodes,a multi-node collaborative camera wakeup method based on location information was studied and designed.This thesis first establishes a network model,adopts a distributed camera node wake-up strategy,and uses a joint dynamic cluster head election algorithm based on node energy on the clustering algorithm;when an event occurs,the ordinary node senses the event location and then sends it to the camera node,and the camera node Wake up and event collection based on event level and remaining energy.Aiming at the problem of image transmission after image acquisition,this paper first analyzes and analyzes classic image coding algorithms based on wavelet transform:embedded zero-tree wavelet coding algorithm(EZW)and hierarchical wavelet tree set segmentation algorithm(SPIHT),combined with distributed transmission,The image is divided into channels and divided into blocks,and then wavelet decomposition and compression coding are performed,and transmitted to a target node by using multiple ordinary nodes.This paper comprehensively considers the objective and subjective quality evaluation criteria of the image,and chooses to enhance the 9/7 wavelet transform algorithm,the number of wavelet decomposition layers of 5 layers,and the bit rate of 0.5bpp.it is good.Based on the characteristics of distributed transmission,this paper proposes a distributed image transmission algorithm based on SPIHT,which can effectively reduce transmission energy consumption in WMSNs with multi-hop structure.With the help of MATLAB experimental platform,the multi-node collaborative camera wake-up method based on location information and the SPIHT-based distributed image transmission algorithm were simulated.The experimental results show that the camera wake-up method proposed in this thesis can prolong the survival time of the camera nodes;on the premise that certain image quality is satisfied,the distributed image transmission algorithm proposed in this thesis can extend the network survival time limitedly.