Support for this work from the Office of Naval Research Ocean Acoustics Program is gratefully acknowledged.
Journal of the Acoustical Society of America Express Letters
Underwater acoustics, Noise, Acoustical engineering
Recent work has shown that endfire beamforming of ocean noise can be used to produce images of the seabed layering [Siderius et al., J. Acoust. Soc. Am. 120, 1315–1323 (2006)]. This initial noise imaging technique used conventional beamforming and was later extended to adaptive beamforming that is theoretically optimal. However, there can be problems with adaptive methods, which include extreme sensitivity to random errors, the required averaging time, and computational complexity. Here, the concept of supergain is used to show that delay and sum beamforming can produce nearly the same results as the optimal adaptive methods without the drawbacks.
Siderius, M. (2012). Using practical supergain for passive imaging with noise. The Journal of The Acoustical Society of America, 131(1), EL14-EL20.