Modeling of received signals from interfaces of arbitrary geometry

A new computational technique for determining the received signal in pulse-echo measurements due to a surface of arbitrary geometry is presented. The technique, which is denoted the diffraction response interpolation technique, requires that the reflecting surface be tessellated into rectangular tiles. For each of the four corners of a tile the pulse-echo diffraction responses are calculated, using the velocity potential impulse response combined with the principle of reciprocity. By interpolating linearly between the four responses, the pulse-echo diffraction response at any point on the tile can be estimated. The received voltage due to the entire tile is then found by integrating the response over the tile surface; this integration can be expressed as two time domain filtering operations, yielding a computationally efficient integration. Finally the received signal due to the entire surface is found by adding all tile responses. To validate the technique, it is compared to other numerical pulse-echo modeling techniques and to experimental results.