Image coding and transmission in wireless multimedia sensor networks

Multimedia data is a versatile tool for any kind of application which aims to collect and extract information from a phenomenon. It can be ubiquitously available by the utilization of Wireless Sensor Networks (WSNs). Wireless Multimedia Sensor Networks (WMSNs) have come into existence as a result of this idea. However, handling this combination is a challenging task.This thesis focuses on image coding and transmission in WMSNs. Existing coding and transmission schemes are examined and considering the requirements of multimedia transmission together with the constraints of WSN, several contributions are made: A priority based encoding scheme for self-adaptive prioritization of image partitions is proposed, with novel priority measures. The superior performance of this scheme, especially in terms of resources required for it, is shown via experiments and sensor node implementations. A real testbed environment has been set up to observe the effect of channel conditions on transmitted images. By utilizing this testbed, the robustness of an existing coding technique, i.e. error concealment is also validated with over 30,000 transmissions. Hybrid usage of these two schemes is also examined, and a considerable performance gain is achieved. Moreover, an image transmission framework (ITF) is suggested to be coupled with the priority based encoding scheme. ITF is based on bursty and regulated transmission of large image partitions with prioritization via multiple paths. With these attributes, ITF is a promising candidate to satisfy Quality of Service requirements of multimedia applications.