“…As a result, novel approaches have emerged, such as highly integrated sensor systems [3], reflectometers for three-dimensional holographic imaging [4], through-the-wall detection of life signs [5], low-cost radio frequency identification tag characterization [6], and novel high-precision measurement systems [7] – to name but a few. Especially in welding applications, the presently available sensors are based on mechanical effects as, for instance, in tactile sensors [8, 9] or optical effects, for instance, in laser sensors and camera-supported systems [10, 11]. Furthermore, X-ray [12] or ultrasonic-based sensors [13] are used for welding control.…”