Index of content:
Volume 118, Issue 2, August 2005
- ULTRASONICS, QUANTUM ACOUSTICS, AND PHYSICAL EFFECTS OF SOUND 
118(2005); http://dx.doi.org/10.1121/1.1945468View Description Hide Description
Time-reversal focusing is experimentally applied in an elastic medium in the presence of multiple scattering objects on the order of a wavelength in size. The effectiveness of time-reversal is compared to time-delayed focusing and uniform excitation of the transducer array for focusing energy to a desired location within the medium. A filter is also designed to improve the bandwidth of the excitation signal. Time-reversal focusing is investigated in the context of an elastic-wave landmine detection system. Results are presented demonstrating the advantages and limitations of time-reversal in excitation of a resonance in a TS-50 landmine buried in the medium. A special case is presented for a landmine buried in shadow regions where uniform excitation fails to illuminate the target while time-reversal focusing yields improved target illumination.