Nondestructive Evaluation of Aerial Material in Terahertz Imaging Processing

Conventional nondestructive evaluation methods have difficulties in finding internal defects of the aviation foam materials because of its loose structure and thermal insulation. It has become a challenge in nondestructive evaluation field. In this paper, a low-cost terahertz nondestructive evaluation technology is presented. The system uses a 0.1 THz avalanche diode and pyroelectric detector, combined with a 3D printing lens and a three-dimensional scanning system to obtain the interior THz image of the aerial materials. A novel frequency domain filtering algorithm is proposed to obtain higher quality internal image aiming at reducing the error of scanning system and the diffraction of low-frequency terahertz wave. This technology has important potential value in application of nondestructive evaluation.