Near-field Model of Ultrasonic Array Data

Abstract

<p>One method of efficiently modelling of ultrasonic array data is based on a combination of a ray-tracing approach and far-field scattering amplitude of a scatterer [1, 2]. This technique uses two main assumptions: all scatterers are located in the far-field from each array element and the size of each scatterer is small relative to its distance to array elements. The key part of the model is the so-called scattering matrix, which provides the amplitude and phase of scattered waves in the far-field of the scatterer [3]. However, the far-field approximation fails when the size of the scatterer becomes comparable to its distance to array elements. In this paper a near-field model of ultrasonic array data is developed. In particular, it is shown that the near-field scattering behavior can be extracted from the scattering matrix. The applications of the model are discussed and supported with some modelling and experimental examples.</p>