Date & Time:
Thursday, October 17, 2013; 12:00 PM
In acoustics, one may wish to acquire a wavefield over a whole spatial domain, while we can only make point measurements (ie, with microphones). Even with few sources, this remains a difficult problem because of reverberation, which can be hard to characterize. This can be seen as a sampling / interpolation problem, and it raises a number of interesting questions: how many sample points are needed, where to choose the sampling points, etc. In this presentation, we will review some case studies, in 2D (vibrating plates) and 3D (room acoustics), with numerical and experimental data, where we have developed sparse models, possibly with additional 'structures', based on a physical modeling of the acoustic field. These type of models are well suited to reconstruction techniques known as compressed sensing. These principles can also be used for sub-nyquist optical imaging : we will show preliminary experimental results of a new compressive imager, remarkably simple in its principle, using a multiply scattering medium.
Prof. Laurent Daudet
Paris Diderot University, France
Laurent Daudet is professor of physics at Paris Diderot University, France. After a physics education at the Ecole Normale Superieure in Paris, he received in 2000 a Ph.D. degree in applied mathematics from the Universit? de Provence. He was then a EU Marie Curie Post-doctoral Fellow at the Centre for Digital Music at Queen Mary University of London, UK. Between 2002 and 2009, he has been working as assistant / associate professor at UPMC - Paris 6, in the D'Alembert Institute for Mechanical Engineering. Since 2009, he is full Professor at the Paris Diderot University - Paris 7, with research at the Langevin Institute for Waves and Images. In october 2010, he has been nominated as junior member of the Institut Universitaire de France, a 5-year fellowship to foster excellence in academic research. He serves as associate editor for the IEEE Transactions on Audio Speech and Language Processing, and is author or coauthor of more than 140 publications on various aspects of digital signal processing, mostly based on sparse decompositions with applications to audio and acoustics.