Dottorato in ENGINEERING AND APPLIED SCIENCE FOR ENERGY
AND INDUSTRY

Titolo della tesi: 3D tomography for non-destructive structural inspection and image reconstruction

The aim of this thesis is to contribute to the improvement of the tomography techniques for non-destructive inspection and image reconstruction. A typical approach to 3D image reconstruction is computed tomography, which reconstructs the sought image based on a set of slice projections, relying on the Fourier slice theorem in 2D. This thesis develops an imaging technique based on the Fourier slice theorem in 3D, which relates a set of projections onto planes, that is a 3D Radon transform, to a 3D Fourier transform. By calculating 3D inverse Fourier transforms, the 3D image of the scanned object can be reconstructed. The formulation developed is applied to the reconstruction of the distribution of the light emission density from magnetically confined plasma in 3D, employing the data provided by ENEA which were recorded within the framework of the PROTO-SPHERA experiment. The analysis carried out enabled observation of physical phenomena related to the plasma formation, the rotation of the torus, but above all visualization of the cross sections. On separating the light emission frequencies, also the spatial source of the different emissions was detected.