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Experimental Passive Acoustic Imaging and the Role of Stationary Phase Zones
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 76th EAGE Conference and Exhibition 2014, Jun 2014, Volume 2014, p.1 - 5
Abstract
The averaged cross correlation of the fields recorded by two passive receivers yields the exact Green’s function of the wave propagation in a medium provided that the excitations come from a surrounding surface enclosing the medium. Stationary phase arguments derive the Green’s function retrieval based on constructive interference of rays originating near the line connecting the receivers. Experimental acoustic results supporting this argument are presented. By limiting source positions to the stationary phase regions, it is shown that how these sources contribute coherently which leads to the recovery of the impulse response. The averaged cross correlation shows high degrees of convergence in Fresnel zones around stationary phase points which can be used in imaging application where unlike laboratory situation, the location of the scatterer is unknown.