A new time delay estimation in subbands for resolving multiple specular reflections

In this correspondence, a new time delay estimation procedure is proposed u sing the multiresolution analysis framework through a discrete wavelet tran sform (DWT). Once the signals are decomposed, the time delays are estimated iteratively in each sub-band using two different adaptation mechanisms tha t minimize the mean squared error (MSE) between the reference and primary s ignals in the corresponding sub-band and level. The localization of the min ima of the RISE 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 backs ettered data.