Three-Dimensional Non-Destructive Inspection Using Novel Infrared-Terahertz Fusion Approaches †

The imaging of structures with a complex material composition and geometry is still a challenge in the field of non-destructive testing (NDT). In this study, a non-invasive imaging technique is proposed for the non-destructive inspection of both cultural heritage and natural fiber composites. The proposed technique combines the surface information provided by infrared thermography (IRT) and the internal structure retrieved with terahertz (THz) time-domain spectroscopy using an unsupervised deep residual fusion network. Experiments show that the fusion results contain more material information than a single modality. In addition, 3D imaging has been achieved using the fusion results on natural fiber composites.