The ASPIRE Project - Sensor Networks for Immersive Multimedia Environments

the potential of large, distributed wireless sensor networks (WSN) requires major advances in the theory, fundamental understanding and practice of distributed signal processing, self-organized communications, and information fusion in highly uncertain environments using sensing nodes that are severely constrained in power, computation and communication capabilities. The European project ASPIRE (Collaborative Signal Processing for Efficient Wireless Sensor Networks) aims to further basic WSN theory and understanding by addressing problems including adaptive collaborative processing in non-stationary scenarios; distributed parameter estimation and object classification; and representation and transmission of multichannel information. This highly diverse field combines disciplines such as signal processing, wireless communications, networking, information theory and data acquisition. In addition to basic theoretical research, ASPIRE tests the developed theories and heuristics in the application domain of immersive multimedia environments. The project aims to demonstrate that sensor networks can be an effective catalyst for creative expression. We focus on multichannel sound capture via wireless sensors (microphones) for immer-sive audio rendering. Immersive audio, as opposed to multichannel audio, is based on providing the listener with the option of interacting with the sound environment. This translates to listeners having access to a large number of recordings that they can process and mix themselves, possibly with the help of the reproduction system using some pre-defined mixing parameters. These objectives cannot be fulfilled by current multichannel audio coding approaches. Furthermore, in the case of large venues which are possibly outdoors or even underwater, and for recording times of days or even months, the traditional practice of deploying an expensive high-quality recording system which cannot operate autonomously becomes impossible. We would like to enable 'immersive pres-ence' for the user at any event where sound is of interest. This includes concert hall performances; outdoor concerts performed in large stadiums; wildlife preserves and refuges, studying the everyday activities of wild animals; and underwater regions, recording the sounds of marine mammals. The capture , processing, coding and transmission of the audio content through multiple sensors, as well as the reconstruction of the captured audio signals so that immersive presence can be facilitated in real time to any listener, are the ultimate application goals of this project. So far, we have introduced mathematical models specifically directed towards facilitating the distributed signal acquisition and representation problem, and we have developed efficient multichannel data compression and distributed classification techniques. In the multisensor, immersive audio application, we tested and validated novel algorithms that allow audio …