Summary: 3398 IEEE TRANSACTIONS ON SIGNAL PROCESSING, VOL. 46, NO. 12, DECEMBER 1998
A New Time Delay Estimation in Subbands
for Resolving Multiple Specular Reflections
M. R. Azimi-Sadjadi, S. Charleston, J. Wilbur, and G. J. Dobeck
Abstract--In this correspondence, a new time delay estimation proce-
dure is proposed using the multiresolution analysis framework through a
discrete wavelet transform (DWT). Once the signals are decomposed, the
time delays are estimated iteratively in each sub-band using two different
adaptation mechanisms that minimize the mean squared error (MSE)
between the reference and primary signals in the corresponding sub-band
and level. The localization of the minima of the MSE curves at different
levels and subbands is used in order to arrive at the time delay estimates.
The proposed scheme is then applied to a real-life problem of underwater
target detection from the acoustic backscttered data.
Index Terms--Adaptive filtering, sonar, time delay estimation, under-
water target detection, wavelets.
In underwater target detection, the presence of a target can be
determined by extracting certain clues in the acoustic backscattered