THz Multi-Feature Parameter Imaging of Bonding Defects of High Temperature Composite Materials

Traditional terahertz time-domain spectral imaging is performed by finding a single characteristic parameter of the imaging target. This method has great limitations, it cannot flexibly compare the advantages and disadvantages of imaging with various characteristic parameters, and it is difficult to form a clear contrast to imaging target. This paper proposes a new imaging method, multi-feature parameter imaging, for terahertz non-destructive detection of high temperature composite material bonding defects. This method can improve the overall imaging effect by changing the weight of a single characteristic parameter in the imaging channel. Based on the multi-feature parameter imaging method, the thickness of the upper adhesive layer of 0.05 mm and the lower adhesive layer of 0.15 mm arc preset for debonding defect recognition. Compared with the single-feature parameter imaging method, the image contrast is increased by 2 times.