Development of an optimal array of sensors for the reconstruction of a rigid rough surface based on scattered ultrasound

A novel technique to reconstruct the shape of a two-dimensional rough acoustically rigid surface based on recordings of the scattered acoustic field with an optimised array of sensors is discussed. The method employs inversion techniques which are common in acoustic holography, and is based on a Kirchhoff approximation of the scattered field. The effects of the spatial arrangement of the sensors on the accuracy of the reconstruction are investigated. The optimal layout is identified by means of a genetic algorithm for a representative set of surface statistics. The results will inform the development of a new range of airborne acoustic sensors capable of monitoring the flow conditions of free surface flows remotely, based on the measurement of the spatial scales and dynamics of the water surface.