ASA 127th Meeting M.I.T. 1994 June 6-10

4pUW14. Active, wideband detection of spherical elastic objects of uncertain composition.

M. Wazenski

D. Alexandrou

L. W. Nolte

Dept. of Elec. Eng., Duke Univ., Box 90291, Durham, NC 27708-0291

Active, wideband detection of solid, elastic, spherical objects is approached via optimal detection and estimation theory in conjunction with accurate acoustic modeling. This approach incorporates the inherent uncertainty of critical object parameters, which vary as a function of temperature, pressure, and purity. Robust detection is especially important due to the high sensitivity of scattered fields to these varying parameters, examples of which include size, density (object and medium), compressional wave speed (object and medium), and shear wave speed. The signal model employed assumes that incident signals undergo a spatial and spectral filtering operation which is accurately described by the acoustic model. Detection is limited to spherical objects in white isotropic noise. Illustrative detection examples are presented along with receiver operator characteristic (ROC) performance. [Work supported by ONR, Ocean Acoustics.]