A matched-filter approach to wave migration

Wave migration is a technique in which the reflectivity of the Earth is int erpreted by extrapolating the fields measured on the surface into the groun d. The motivation of this paper is to develop a generalized imaging algorit hm based on a matched-filter that shows a mathematical connection between c urrently used migration techniques. The filter is determined by estimating the received signal when a specific test target exists in the ground. To ke ep the method general, a point scatterer is used as this target, while dist ributed objects are modeled without changing the filter characteristics by a collection of independent point scatterers. Also, the specific forms of t he Green's functions, which describe wave propagation in the ground, are no t included in the formation of this approach leaving more freedom in the im plementation. When the filter is applied to measured data of a monostatic s urvey, the resulting method becomes a forward scattering problem in which t hese data become time-reversed current sources. Next, specific forward scat tering techniques are applied to this matched-filter approach and the resul ting methods are compared to traditional migration techniques. In doing so, we find that the general form of most migration techniques can be shown us ing a matched-filter, while the major differences lie in the actual interpr etation of the wave propagation that is used to implement the filter. The s imilarities of the matched-filter-based approaches to traditional technique s are used to show a connection and general overview of wave migration. Fin ally, these methods are applied to data collected over pipes buried in sand . (C) 2000 Elsevier Science B.V. All rights reserved.