Reversible quasi-holographic line-scan processing for acoustic imaging and feature isolation of transient scattering

Abstract

Transient acoustic scattering data from objects obtained using a one-dimensional line scan or two-dimensional raster scan can be processed via a linear quasi-holographic method [K. Baik, C. Dudley, and P. L. Marston, J. Acoust. Soc. Am. 130, 3838–3851 (2011)] in a way that is reversible, allowing isolation of spatially or temporally dependent features [T. M. Marston et al., in Proc. IEEE Oceans 2010]. Unlike nearfield holography the subsonic wavenumber components are suppressed in the processing. Backscattering data collected from a collocated source/receiver (monostatic scattering) and scattering involving a stationary source and mobile receiver (bistatic) may be processed in this manner. Distinct image features such as those due to edge diffraction, specular reflection, and elastic effects may be extracted in the image domain and then reverse processed to allow examination of those features in time and spectral domains. Multiple objects may also be isolated in this manner and clutter may be removed [D. J. Zartman, D. S. Plotnick, T. M. Marston, and P. L. Marston, Proceedings of Meetings on Acoustics 19, 055011 (2013) http://dx.doi.org/10.1121/1.4800881]. Experimental examples comparing extracted features with physical models will be discussed and demonstrations of signal enhancement in an at sea experiment, TREX13, will be shown. [Work supported by ONR.]