Lamb Wave Imaging of Defects in Aluminum Plate using Total Focusing and Image Fusion

Imaging defects by Lamb wave is an efficient way to locate and evaluate damages in aluminum plate. In this paper, an array of piezoelectric elements is mounted onto the plate for defect imaging. The full matrix data that include each transducer acting as emitter and receiver are obtained. The total focusing method is used to image the defects using the full matrix data. Furthermore, various frequencies have been used to image the defects, the localization error and noise in the images have been compared. It has been found that different artifacts exist in images with different frequency excitation. Therefore, the fusion of multi-frequency data has been proposed to combine the images obtained under different frequencies. The results show that the fusion can effectively improve the accuracy of defect localization and can significantly enhance the quality of defect image.