X-Ray

Sparse source travel-time tomography of a laboratory target: accuracy and robustness of anomaly detection

“…An inversion estimate can then be produced, for instance, through a robust sampling-based (e.g., Markov chain Monte Carlo) method [1,41,53]. Such an inversion procedure can be interesting, for instance, in ultrasonic detection and classification of breast lesions [28][29][30][31][32]. Other potential inversion approaches to be used in the current context of signal sparsity include, for instance, the compressive sensing [54] and transdimensional Bayesian methods of geophysics [55][56][57].…”

“…Another project in progress aims to investigate the accuracy of the inversion with coarser materials, such as plaster or concrete, which can include a grained structure, cracks and casting defects hindering the signal and causing considerable model noise. Our general future goal is to provide complementary and more applied knowledge to serve asteroid tomography, ultrasound testing [26,[37][38][39], tomography of tree roots [36] as well as medical imaging [31,32].…”

“…The internal structure of the cube was also analyzed via high resolution x-ray computed tomography (CT) scan [32] to obtain a reference solution as well as to verify the quality of the casting. A structural illustration of the cube has been included in figure 1.…”

“…Moreover, the high permittivity of the asteroid minerals [17][18][19][20] is likely to lead to strongly randomized or noisy reflections 3 due to which the present inversion strategy utilizing the direct part of the signal can be advantageous [5]. In addition to asteroid tomography, other potential applications of the present sparse source inversion approach include on-site material testing and inspection [21][22][23][24][25][26][27], biomedical ultrasonography [28][29][30][31][32], as well as plenty of atmospheric, pedospheric, geological, and biological investigations utilizing travel time data [33][34][35], such as recovery of the root-zone structure of a tree [36].…”