A new tomographic reconstruction method for anisotropic materials

A new, tomographic reconstruction method, C-ART, for anisotropic-materials is presented which accounts for directional dependence of sound velocity in the material. The method reconstructs a two dimensional object, with internal defects, in terms of independent parameters, like elastic constants of the material. Single mode, measurement data is used for the reconstruction. The proposed method is a two-stage process, which involves conventional ART like corrections in the first stage and solution of a set of non-linear equations in the second stage. In the present work, three simple anisotropic functions, simulating direction dependent behaviour, are considered to evaluate the performance of the method. The method is found to perform well even for strong anisotropy. The reconstruction in presence of multiple defects is also attempted. It is shown in this paper that a prior knowledge of the object field is not required as an initial guess. The technique has promise for ultrasonic tomography of composite materials.