Nuessler, D.D.NuesslerSchubert, M.M.SchubertKose, S.S.KosePohl, N.N.Pohl2022-03-052022-03-052017https://publica.fraunhofer.de/handle/publica/25211110.1109/MMM.2017.2712018Providing a deeper look beneath the surface is a key function of product security and materials scanners [1]. Until recently, only ultrasonic and X-ray systems made this possible [2]. Now, electromagnetic waves, which allow a view through nonconducting materials, offer a competitive alternative [3]. While examinations using X-ray methods are common, because of required safety regulations, this option is relatively costly. Current optical sensor systems, on the other hand, are relatively inexpensive, but they offer only limited information about the internal structure of the device under test (DUT).en621journal article