Research Of Distributed Image Compression Scheme In Wireless Multimedia Sensor Networks

With the development of sensor technology, micro-electronic technology, embeddedcomputation technology and power-aware wireless communication technology, Wireless sensornetwork (WSNs) is a new research area of computer science and has a great applica tio n future inthe military and civil area. The characteristics of WSNs are distinct from traditiona l wirelessnetworks, such as data-centric, applica tion-rela ted, resource-limited, etc, which raise new issuesfor the research in WSNs. Wireless Multimed ia Sensor Networks(WMSNs),developed fromtraditiona l Wireless Sensor Networks(WSNs), is a novel sensor network integrating sensationfunctions of multimed ia streaming (e.g. audio, video, ima ge). Compared with traditiona l WSNswhich can only measure simple sealar physica l phenomena such as temperature,pressure,humid ity,or location of objects, Wireless Multimed ia Sensor Networks are able to ubiq uitouslyretrieve multimed ia content such as video,audio streams and still ima ges. Potential applica tionsof Wireless Multimed ia Sensor Networks span a wide spectrum from military to industria l,fromcommercia l to environmental monitoring.Wireless Multimed ia Sensor Networks have broad applica tion foreground in military,especia lly in constructing the integrative information system in battle field. This dissertationconcentrates its attention on the distributed information Processing in Wireless Multimed iaSensor Networks. The ma in contents and contributions of this dissertation are as follows .A kind of clustering method applied for WMSNs is presented, and it is compared to thetraditiona l LEACH protocol in experiment, the result shows that the method presented in thisthesis has ma ny advantages compared to LEACH protocol, the prolonging of the lifetime ofnetwork, the covering of network, the bala nce of load ing ,etc.This thesis concludes the limitations of the solutions of ima ge compression by now inWMSN, and based on the study of DCT conversion and JPEG ima ge compression algorithm, adistributed ima ge compression algorithm that suits for WMSNs is presented. Stimulation resultshows that this algorithm has ma ny advantages, compared to"centralized processing", thisdistributed processing algorithm can prolong the lifetime of the whole network sharply, the consumption of energy is more bala nced, it has outsta nding performa nce in ma ny ways. Theapplica tion of this algorithm in WSNs can promote the applying development of WMSNs.A design of multi-med ia hardware prototype system is presented. The design of hardwarenode of ima ge sensor, the design of drive program, the design of user space program and thedesign of client program are introduced. After that, the whole ima ge processing is presented,including acquisition, encoding, transmission, decoding and the restitution of ima ge.