Image reconstruction of defects 100 mm deep within SN sample using inverse problem solving

This study considers methods of inspecting 100mm-deep defects in ceramic materials. The acoustic velocities of ceramic materials are six to eight times that of water. In submerged UT inspection, it is difficult to manufacture an acoustic point-focus lens that can focus deeply inside ceramic materials compared with metal material. A point-focus UT probe and a probe-array to inspect faults deep inside ceramic material were developed and applied to metal and ceramic samples. In addition, a synthesis aperture program and inverse problem solving programs using Truncated Singular Value Depsoition (TSVD) were developed to reconstruct images of defects in samples; these programs were compared.