Research Projects
Acoustic imaging
Professor Peter Gough and Dr Michael Hayes
Synthetic aperture Sonar (SAS) is a technique for high resolution imaging of the seafloor and is the sonar analog of synthetic aperture radar. SAS attains its high along-track resolution by using a “synthetic aperture”, achieved by coherent processing of reflected acoustic signals collected along the path of a towed transmitter/receiver. The performance of current SAS systems is limited by distortions due to platform motion and aperture undersampling. The objective of our research program is to develop methods to produce high quality acoustic images of the seafloor using synthetic aperture techniques. This involves development of sophisticated computer algorithms to compensate for platform motion, modelling ocean acoustic phenomena, design and construction of advanced electronic instrumentation, and underwater engineering. Experiments are conducted mainly in Lyttelton Harbour but also in Auckland and Sydney Harbours.
More information can be found on the Acoustics Research Group website.
The SAS towfish, "KiwiSAS", designed and built by the Acoustics Research Group
Top: Unprocessed data from a sunken boat in Sydney Harbour. Bottom: The same data after synthetic aperture processing.
Sample publications:
K.A. Johnson, M.P. Hayes and P.T. Gough, A method for estimating the subwavelength sway of a sonar towfish, IEEE J. Oceanic Eng., 20, 258-267 (1995).
P.T. Gough and D.W. Hawkins, Imaging algorithms for a strip-map synthetic aperture sonar: Minimizing the effects of aperture errors and aperture undersampling, IEEE J. Oceanic Eng., 22, 27-39 (1997).
H.J. Callow, M.P. Hayes and P.T. Gough, Wavenumber domain reconstruction of SAR/SAS imagery using single transmitter and multiple-receiver geometry, Electron. Lett., 38, 336-338 (2002).