ASA 124th Meeting New Orleans 1992 October

4pUW5. A unified approach to acoustical reflection imaging.

A. J. Berkhout

Lab. of Seismics and Acoust., Delft Univ. of Technol., P.O. Box 5046, 2600 GA Delft, The Netherlands

A discrete theory is proposed that represents acoustical reflection measurements in terms of a so-called data matrix. One column of the data matrix is related to one source position; one row is related to one detector position. In the proposed theory, the data matrix is expressed in a sequence of matrix operators. Those operators quantify the physical processes of emission, downward propagation, reflection, upward propagation, and detection in inhomogeneous media. The concept of optimum ``illumination'' is introduced. Using the matrix formulation, it is shown how to design an experiment that is optimum for a specific target area. The imaging process is formulated in terms of double inversion: one inversion for the downward propagation operator and one inversion for the upward propagation operator. It is shown that double focusing (in emission and in detection) represents an economic version of the double inversion process. The proposed theory is pre-eminently suited to discuss imaging technology on a conceptual level.