Past Seminars- Inverse Problems and Imaging

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  • Peijun Li
    Tue Jun 12, 2012
    2:00 pm
    We consider the scattering of a time-harmonic plane wave incident on a two-scale heterogeneous medium, which consists of scatterers that are much smaller than the wavelength and extended scatterers that are comparable to the wavelength. A generalized Foldy-Lax formulation is proposed to capture multiple scattering among point scatterers and...
  • Mark A. Anastasio
    Tue May 15, 2012
    2:00 pm
    Photoacoustic tomography (PAT) is an emerging soft-tissue imaging modality that has great potential for a wide range of biomedical imaging applications.  It can be viewed as a hybrid imaging modality in the sense that it utilizes an optical contrast mechanism combined with ultrasonic detection principles, thereby combining the advantages of...
  • Oleg Imanuvilov
    Tue May 8, 2012
    4:00 pm
    We prove that if for the isotropic Lamé system the coefficiem $\mu$ is a positive constant then both coefficents can be reconstructed from the partial Cauchy data.
  • Luca Rondi
    Tue Mar 13, 2012
    2:00 pm
    Many techniques developed for free-discontinuity problems, arising for example in imaging or in fracture mechanics, may be successfully applied to reconstruction methods for inverse problems whose unknowns may be characterized by discontinuous functions. We show the validity of this approach both from the theoretical point of view, by a...
  • Hongyu Liu
    Tue Mar 6, 2012
    2:00 pm
    In this talk, we shall consider the near-invisibility cloaking in acoustic scattering by non-singular transformation media. A general lossy layer is included into our construction. We are especially interested in the cloaking of active/radiating objects. Our results on the one hand show how to cloak active contents more efficiently, and on the...
  • Andras Vasy
    Tue Feb 28, 2012
    2:00 pm
    Waves reflecting/refracting/transmitting from singularities of a metric (e.g. sound speed) satisfy the law of reflection. One expects that if the singularities are sufficiently weak, in terms of differentiability (conormal order) then the reflected singularity is weaker than the transmitted one, in the sense that it is more regular. In this joint...
  • Lauri Oksanen
    Thu Jan 12, 2012
    4:00 pm
    We consider boundary measurements for the wave equation on a bounded domain $M \subset \R^2$ or on a compact Riemannian surface, and introduce a method to locate a discontinuity in the wave speed. Assuming that the wave speed consist of an inclusion in a known smooth background, the method can determine the distance from any boundary point to the...