Near–Field Crack Localization using Spectral Estimation Methods

Abstract Non–Destructive Inspection (NDI) using phased arrays is used to detect defects in structures of Aerospace vehicles, such as cracks, corrosion spots, composite material delaminations and others. Ultrasonic Imaging, an advanced NDI technique, relies on advanced signal processing methods to accurately localize defects. The Multiple Signal Classification (MUSIC) is a high resolution spectral estimation method typically used for Angle of Arrival (AOA) estimation. This work examines the applicability and performance of the MUSIC method for localization, rather than AOA estimation, of point defects and finite–length cracks in structures. The advantages of MUSIC over traditional methods like the Delay and Sum Beamformer (DSBF) are highlighted.