Ultrasonic Pulse-Echoes and Eddy Current Testing for Detection, Recognition and Characterisation of Flaws Detected in Metallic Plates

In order to improve manufacturing quality and ensure public safety, components and structures are commonly inspected for early detection of defects or faults which may reduce their structural integrity. Non Destructive Testing (NDT) and Evaluation (NDE) techniques present the advantages of leaving the specimens undamaged after the inspection. NDT involves treating defect detection and characterization as inverse problems. In experimental NDT/NDE, the available measurement data are exploited in order to some clues may emerge in the inspection signal that are possibly representative of structural modification of the specimen, like cracks, delaminations and porosities. In this paper, a comparison of Ultrasonic Pulse-Echoes and Eddy Current Testing techniques is presented to investigate critical flaw-structure configuration, such as porosity in metallic plates. The proposed procedure exploits a fuzzy classifier that receives a set of extracted features worth of inputs by means of Wavelet Transform. The output of the system is a sort of codification related to each kind of damage (so-called class). In order to refine the procedure, Shannon Fuzzy Entropy has been taken into account.