Multimedia Data Processing and Delivery in Wireless Sensor Networks

In the last few years, multimedia processing inWireless Sensor Networks (WSNs) has become a promising technology. It has the potential to enable a large class of applications, most of them related to surveillance and locating (i.e. target detection and tracking, border protection, patient and elderly assistance, people and object identification, environment monitoring, fire detection, industrial control, ...). To achieve an effective Quality of Service (QoS) in multimedia applications, special node and network capabilities are required. For example, compared to normal WSN nodes, multimedia nodes need additional hardware resources for memory, processing capability, transmission rate and energy. A Wireless Multimedia Sensor Network (WMSN) is a special WSNmade up of several multimedia sensor nodes, specially designed to retrieve multimedia content such as video and audio streams, still images, and scalar sensor data from the environment. In this paper, we focus on a different, but also very practical and common, sort of wireless network: theHeterogeneousNetworks, wheremultimedia and non-multimedia nodes deliver data. In this scenario, the non-multimedia node constraints have to be taken into account to deliver multimedia data through multi-hop paths. Generally, collaborative processing makes no sense in this case. Although in-sensor multimedia processing is a fundamental topic in order to obtain an effective data reduction. Currently, research challenges in designing multimedia applications on WSNs include, but are not limited to the following: