Ultrasonic Tomographic Imaging of Anisotropic Solids

Abstract

Tomographic imaging is a technique to determine values of a spatially varying parameter on a cross-sectional slice through an object. In the ultrasonic case of tomography, waves are propagated through the sample between a series of source and receiver locations placed in a plane around the object. These locations are chosen such that the rays pass through as large a fraction of the object plane as possible, and to conform to any requirements for regular positioning in the reconstruction procedure. If the propagation delay is measured for each raypath between source and receiver, the acoustic slowness can be determined along the cross-sectional plane (slowness is the reciprocal of velocity). There are in existence a variety of algorithms that can construct tomographic images, such as filtered backprojection and algebraic reconstruction tomography (ART) [1,2].