Fusion of visual and eddy current inspection results for the evaluation of corrosion damage in aircraft lap joints

The fusion of data from Edge of Light (TM) (EOL) and eddy current inspections of aircraft lap joints is investigated in this study. The pillowing deformation caused by corrosion products is estimated by the EOL technique first. Eddy current (ET) techniques, e.g. multi-frequency eddy current testing (MF-ET) and pulsed eddy current testing (P-ET), car. provide depth-sensitive inspections of fuselage joints. The objective of this study is to investigate how the testing results obtained from the two different methods correlate to each other and what kind of complementary information is available in each result. This work contains two steps. First, the EOL inspection is quantified through a calibration process where a laser displacement sensor is used to provide the reference. The EOL estimation is for the total material loss while the eddy current or pulsed eddy current testing is employed to provide the complementary information on the remaining thickness. Second, the ET data are fused with the principle component analysis method and the results are calibrated by a calibration experiment. Finally, the bottom layer corrosion is estimated through the subtraction of EOL and ET results. The preliminary results are presented in this paper.